View Full Version : Milspec and beyond
I read the link posted in the OLY arms thread concerning Oly Arms response to Rob_S. I hadn't seen that before.
It, and Grant's milspec thread, got me thinking about milspec re: how do we know what is "above" milspec.
The oly arms letter claimed that chrome lining and a different barrel steel made for a better rifle than military specifications. It got me thinking; If milspec is the lowest accepted standards how do we, the laymen, gauge what WOULD make for a better than milspec rifle?
I understand the opinion around here is knight's is considered beyond milspec. So what are they doing that is going beyond?
What is a better barrel steel? What is a better FSP? what is a better x? etc.etc. on down the milspec list.
Any thoughts? Is there a reference or "chart" that contains and discusses the options that would be BETTER or BEYOND milspec? What combination of materials would make a "better than" milspec rifle?
Sttrongbow
01-29-09, 21:11
I read the link posted in the OLY arms thread concerning Oly Arms response to Rob_S. I hadn't seen that before.
It, and Grant's milspec thread, got me thinking about milspec re: how do we know what is "above" milspec.
The oly arms letter claimed that chrome lining and a different barrel steel made for a better rifle than military specifications. It got me thinking; If milspec is the lowest accepted standards how do we, the laymen, gauge what WOULD make for a better than milspec rifle?
I understand the opinion around here is knight's is considered beyond milspec. So what are they doing that is going beyond?
What is a better barrel steel? What is a better FSP? what is a better x? etc.etc. on down the milspec list.
Any thoughts? Is there a reference or "chart" that contains and discusses the options that would be BETTER or BEYOND milspec? What combination of materials would make a "better than" milspec rifle?
Keep in mind that specs are intended to do one things:
Guarantee a consistent level of minimum performance. Specs can also limit performance. But when you're making a million widgets (or rifles), being able to a have a predictable level of performance is very important. So specs can include materials, design, manufacturing technique, finishing, and testing (and some other things I doubtless forgot).
It's easy for a company to say their product is "better than milspec," and it might be. But often such a claim is very narrow... it's based on materials, design, or something else. Very often, though, some important aspect is left out, or ignored (testing.... adherence to tolerances, whatever). Ultimately the marketplace will decide if you're product is really "just as good as" or "better than."
For example, LMT's MRP rifles are "not to spec," but I've never heard anyone suggest they are inferior. OTOH, Oly's claims of "just as good as" are just not backed up by field experience. It's Caveat Emptor, as always.
i've had these same thoughts- the fact of the matter is that you summed it up correctly- milspec is the standard, it's not the best. it is, however, the best compromise, in my opinion, between reliability and accuracy in a fighin gun, because it seems one often encroaches on the other. lotta match shooters either use ultra heavy or ultra light BCGs for smoother recoil... this subtracts from reliability, but for their purposes it's "better" than milspec. likewise, most of my guns have stainless barrels... not as durable, but more accurate (helps make up for me). for my purposes stainless is better than milspec.
i do, however, think that while maintaining a minimum standard, it also promotes stagnation. look at all these recent threads on different BCGs/bolts- half the people say "maybe it's worth checking out?" while everyone else says "it's not milspec, don't use it!" so even though there probably are bolts out there that are longer lasting than "milspec," nobody will give it a shot.
Keep in mind that specs are intended to do one things:
Guarantee a consistent level of minimum performance. Specs can also limit performance. But when you're making a million widgets (or rifles), being able to a have a predictable level of performance is very important. So specs can include materials, design, manufacturing technique, finishing, and testing (and some other things I doubtless forgot).
It's easy for a company to say their product is "better than milspec," and it might be. But often such a claim is very narrow... it's based on materials, design, or something else. Very often, though, some important aspect is left out, or ignored (testing.... adherence to tolerances, whatever). Ultimately the marketplace will decide if you're product is really "just as good as" or "better than."
For example, LMT's MRP rifles are "not to spec," but I've never heard anyone suggest they are inferior. OTOH, Oly's claims of "just as good as" are just not backed up by field experience. It's Caveat Emptor, as always.
This is what I'm getting at. Sans testing, it's only a claim. What milspec to me is, beyond what grant explained and you just mentioned, is a particular equation that has been tested and proven to work.
My question remains though: What would make a rifle "better than milspec". If it can't be answered than so be it. I personally believe that it can be answered but doing so would require EXTENSIVE testing and evaluation. For someone to change a variable in the equation and call it "better than" is simply not enough.. IMO at least.
That being said; One has to evaluate which military specifications fit their needs. Things like, Parkerize under FSB or double heat shield handguards may not matter to some. The minute any rifle, including colt, takes on a modification such as a FF rail, or even optic, it looses that "milspec" stamp. Is this correct?
So let's move to the next portion. Rob did a great job compiling from others and authoring his own descriptions, opinions, and facts on what military specifications might be more important than others. i think we can agree that adhering STRICTLY to the milspec guidelines is conducive to all. It is however gravely important to stick the ones that affect reliability and functionality. I'm aware that most skip to the pretty spread sheet with blue boxes and "x"s without reading the description and thus, are dumber for it.
Just putting things out there for discussion.
Any gun is as good as the weakest part of that gun. Cost has to be factored in . If a gun costs 3 times as much as another but lasts only twice as long is it better. The biggest problem with the entire M4 world is that gun is a compromise. The gun and round (M855) were originally designed around a 18" bbl platform. The gas system,buffer tube bolt, everything. When we compromised the design by hacking off the bbl and buffer tube things got funny. We(industry) have been trying to fix this compromise of stoner's design since it occurred. We have tried boosters,buffers,rubber bumpers, rocket wire extractor springs ,pistons , dual extractor springs , you name it. Most of the developments that became the M4 actually came out of a tanker gun program. The M4 was about as right as we could get it at the time. For procurement logistics and other reasons the design was frozen at this point. Can we (industry) make a better gun than a M4 perhaps but probably not for the same dollar and 100% parts commonality. As I stated a gun is as good as it's weakest link and the weakest link in 16" and under short gas system guns is the extractor . I would say it is a 3000 round life cycle. If I can change this $5 part on schedule then there should not be a problem. If I can't then that 5$ part could cause my entire rifle to be useless and as a soldier or someone else who depends on their rifle this way this 5$ part could cost them their life. The next point of failure would perhaps be the bolt. I'm not going to quote life cycle here because it is a not totally agreed on subject but with suppressor use it is certainly more limited. Last is the bbl. A hammer forged chrome lined bbl is going to last longer than other types of bbls. It may or may not be as accurate but when improperly maintained a HF CL bbl will beat out all others period. I am going to call the life cycle of a good HF CL bbl to be 20,000 rounds. There are certainly reports of them lasting shorter under heavier firing schedules , and it won't explode at this point but the accuracy will start to deteriorate at this point.
KAC has tried to build a rifle that all the parts will last the full 20,000 rounds. Zero parts replacement. The downside is it costs more and lack of parts compatibility .
The bottom line as I have said before the Mil spec requirement is certainly there for a reason. It is possible to build a gun that will perform better than a mil-spec gun that may not meet the requirement. Many people claiming Mil-spec may not actually meet that requirement for something as obscure as ISO certification.
There are so many good choices out there in the AR world . So many good companies doing innovative stuff . I would hate to see industry not advance the AR design because we are held to trying to just build mil-spec guns.
At what point does a gun not become an AR anymore? We all know that the non-full curve magazine is a weak link. Would you guys be willing to throw all your mags away in order to achieve a higher level of reliability? We(US gov't) were not willing to take that step with the SCAR.
Just some thoughts ;sorry for a rambling post , it is not meant to be a rant.
Any gun is as good as the weakest part of that gun. Cost has to be factored in . If a gun costs 3 times as much as another but lasts only twice as long is it better. The biggest problem with the entire M4 world is that gun is a compromise. The gun and round (M855) were originally designed around a 18" bbl platform. The gas system,buffer tube bolt, everything. When we compromised the design by hacking off the bbl and buffer tube things got funny. We(industry) have been trying to fix this compromise of stoner's design since it occurred. We have tried boosters,buffers,rubber bumpers, rocket wire extractor springs ,pistons , dual extractor springs , you name it. Most of the developments that became the M4 actually came out of a tanker gun program. The M4 was about as right as we could get it at the time. For procurement logistics and other reasons the design was frozen at this point. Can we (industry) make a better gun than a M4 perhaps but probably not for the same dollar and 100% parts commonality. As I stated a gun is as good as it's weakest link and the weakest link in 16" and under short gas system guns is the extractor . I would say it is a 3000 round life cycle. If I can change this $5 part on schedule then there should not be a problem. If I can't then that 5$ part could cause my entire rifle to be useless and as a soldier or someone else who depends on their rifle this way this 5$ part could cost them their life. The next point of failure would perhaps be the bolt. I'm not going to quote life cycle here because it is a not totally agreed on subject but with suppressor use it is certainly more limited. Last is the bbl. A hammer forged chrome lined bbl is going to last longer than other types of bbls. It may or may not be as accurate but when improperly maintained a HF CL bbl will beat out all others period. I am going to call the life cycle of a good HF CL bbl to be 20,000 rounds. There are certainly reports of them lasting shorter under heavier firing schedules , and it won't explode at this point but the accuracy will start to deteriorate at this point.
Understand and agree.
KAC has tried to build a rifle that all the parts will last the full 20,000 rounds. Zero parts replacement. The downside is it costs more and lack of parts compatibility .
And I think most understand and appreciate this compromise.
The bottom line as I have said before the Mil spec requirement is certainly there for a reason. It is possible to build a gun that will perform better than a mil-spec gun that may not meet the requirement. Many people claiming Mil-spec may not actually meet that requirement for something as obscure as ISO certification.
What I'm attempting to learn by starting this thread is particulars such as:
is there a better barrel steel than the one denoted in milspec?
better extractor insert?
better gas tube diameter?
better bolt?
etc.
There are so many good choices out there in the AR world . So many good companies doing innovative stuff . I would hate to see industry not advance the AR design because we are held to trying to just build mil-spec guns.
I can agree but would add the following. If we had everyone making milspec ARs as a rule and not the exception I think the competition would move towards price and THEN further innovation. The vast majority of ARs on and continually brought to the market are below milspec. Just getting to the point where everyone was building the same quality stuff would suffice me in the interim.
At what point does a gun not become an AR anymore? We all know that the non-full curve magazine is a weak link. Would you guys be willing to throw all your mags away in order to achieve a higher level of reliability? We(US gov't) were not willing to take that step with the SCAR.
Would I be willing to toss my mags in order to achieve a higher level of reliability? No. But I would certainly stop buying last gen magazines if the next product in the pipeline provided a greater reliability score that was observable, measurable, and repeatable. Pmag is a perfect example.
.gov is another animal and you are familiar with it more than most I'm sure. As far as the leo/civi market is concerned, we are excited at the prospect of something like the SCAR or Magpul masada/bushmaster ACR. I have no emotional attachment to the AR platform that would preclude me from dropping a dime on another system that was as versed. By versed I mean, availability of parts/ammo/support etc. Again, speaking of compromise here. I understand your companies PDW to be quite a weapon but... If the availability of the above mentioned items is scarce... I can't personally make the compromise to switch. I need my tools to work and when they don't, I need to be able to have rapid access to the resources that will get me back in the fight. If ANY other weapon system can improve on the AR's reliability, leathality, AND availability of parts/ammo/etc. than I will be the FIRST one in line with cash in hand. Until that time, I'm forced to play with what I know.
Just some thoughts ;sorry for a rambling post , it is not meant to be a rant.
I know I speak for a lot of people when I say we appreciate you posting in this thread and on this forum. It's an amazing resource to have the horses mouth, as it were, right here for us to talk to. The owner and moderators have done a great job of keeping this place mature therefor proving professionals a comfortable environment in which to converse.
I'm kind of surprised that the .gov is willing to stay with the m16/m4 for as long as it did. If you look the the guns the Army had just since WWII, there was the M1 Garand (30.06), M1 Carbine (.30 cal), M14 (7.62x51), then the M16/M4 (5.56)
Thats 4 guns and calibers within the span of 40 years.
If the Stoner design had to be compromised to come up with the m4, I wonder why the .gov simply didn't start from scratch...
I'm kind of surprised that the .gov is willing to stay with the m16/m4 for as long as it did. If you look the the guns the Army had just since WWII, there was the M1 Garand (30.06), M1 Carbine (.30 cal), M14 (7.62x51), then the M16/M4 (5.56)
Thats 4 guns and calibers within the span of 40 years.
If the Stoner design had to be compromised to come up with the m4, I wonder why the .gov simply didn't start from scratch...
$$$$$$$$$$$$$
While I generally can't stand the way most people use the phrase, I think that "better for your use" may be appropriate in some cases.
To use a car as an example, and to take cars from the same maker and price range, Both the Corvette and the fully loaded Silverado are of equal "quality" but one is better for some uses vs. the other.
To bring this back into firearms, and ARs, lets look at barrel steel. First you have stainless vs. carbon steel, then there's 4140 vs. 4150 carbon, then there's grades of 4150! (go here (https://www.m4carbine.net/showthread.php?t=37) for more on this) Different steels are going to be preferable for different uses so while Mil-B-11595E 4150 may be best for "hard use", long-range accuracy buffs may prefer stainless. You can't quantify "better" without "for xyz".
There are also a lot of things that aren't covered in the EoF or Chart, and there are a lot of things that can't be quantified or proven. I spent an hour talking with Dean Caputo at SHOT, and he clarified a lot of things for me, and opened my eyes to a lot of things that I didn't know. The further I get down the rabbit hole the more I come back to "just buy a 6920 and put an Aimpoint and a light on it" as an answer to everything. However, many people can't afford (or find) a 6920, and many people don't need a carbine at that level.
This is why the Explanation of Features that goes with the Chart is so important. It starts off by saying that the criteria for selection is based on "hard use" (I actually prefer the term "critical use", but whatever) and then goes on to lay out the desired features and options for such use. Someone wanting to shoot prairie dogs at 500 yards would be stupid to use the Chart to make their firearm selection, although certain criteria may carry over (not being a prairie dog shooter, I have no idea which though).
Strictly in terms of the Chart and EoF, they have moved well beyond what's "milspec" or what's "in the TDP". Both of these things were the basis for the initial list of features and the original Chart, but the whole project has morphed more into a list of desirable features in a defensive use carbine. I would prefer that "milspec" and "TDP" be banished from all discussion of the Chart as the EoF now actually explains things past the juvenile "because the spec says so". Teach a man to fish, and all that.
In regards to the thread in question, notice that the Oly rep keeps asking everyone else to produce the "milspec" or the "TDP", yet himself constantly refers to testing, reports, preferences, etc. of the US Military and never once produces documents to support his own claim.
Jay Cunningham
01-30-09, 05:50
I spent an hour talking with Dean Caputo at SHOT, and he clarified a lot of things for me, and opened my eyes to a lot of things that I didn't know. The further I get down the rabbit hole the more I come back to "just buy a 6920 and put an Aimpoint and a light on it" as an answer to everything. However, many people can't afford (or find) a 6920, and many people don't need a carbine at that level.
Agree.
Spend three days in Ken Elmore's class and you get much the same in the way of open eyes.
My own philosophy right now is "back to the future"... and it works out well since everyone must have the latest and greatest new gadget right NOW even if they have no requirement for it or even if their "old" gadget did the job just fine.
In regards to the thread in question, notice that the Oly rep keeps asking everyone else to produce the "milspec" or the "TDP", yet himself constantly refers to testing, reports, preferences, etc. of the US Military and never once produces documents to support his own claim.I work as a contractor in the Department of Defense acquisition field, and I can say with a good measure of confidence that most unclassified MIL-SPECs should be available to anyone that wants to see them. Many can be found on the internet. Of course that is assuming one can find out all the MIL-SPECs that are in the M4 TDP.
The TDP si another story, however. It is likely that the Government doesn't own the M4 TDP outright, but has what is known as "Government Purpose Rights" (GPR). With GPR, the Government can use the data for their own purposes (like setting up a weapon overhaul facility), but is prohibited from releasing the complete TDP to any other manufacturer. The Government may elect to purchase Unlimited Data Rights from Colt, which allows the Government to release the TDP to anyone they desire, but the cost may be prohibitive (it can run in the millions of dollars). Unless the Government does purchase unlimited data rights, the chances that Oly will ever see the complete M4 TDP are slim to none.
My own philosophy right now is "back to the future"... and it works out well since everyone must have the latest and greatest new gadget right NOW even if they have no requirement for it or even if their "old" gadget did the job just fine.I recently saw a show on Discovery Channel (Future Weapons, I believe) where a new Israeli CQB weapon based on the M4 was being demonstrated. When the American reporter, a former Navy SEAL, asked why they based the new gun on a forty year old design, the Israeli designer casually replied "Because Stoner was a genius". It's no wonder the M16 and M4 continue to be the primary battle weapons of many of the world's armies.
Sttrongbow
01-30-09, 07:48
i do, however, think that while maintaining a minimum standard, it also promotes stagnation. look at all these recent threads on different BCGs/bolts- half the people say "maybe it's worth checking out?" while everyone else says "it's not milspec, don't use it!" so even though there probably are bolts out there that are longer lasting than "milspec," nobody will give it a shot.
You've summed it up nicely. There is a danger in demanding that it "be to spec" that we don't see any innovation. You'll see that in enthusiast forums and the like. But frankly the AR world is not short on innovation. We're seeing all kinds of cool stuff. It's one of the joys of being an AR owner... what gizmo can I try out next!?
When SCARs are common, they'll be fun for a bit, and great "got to" guns, but not nearly as much fun as the AR platform to tinker with.
There have been claims made as to "better" in the great bolt debates of 2009. However, nothing has been put forth to validate these claims. Therefore, the claims aren't worth the time it takes to type them.
If someone says their bolt is better they need to be able to qualify and quantify that statement.
You guys are having an OLY SUCKS thread without me??? .... the president of the Oly Haters society???
I remember when that moron from OLY cried to the staff on TOS about my account name.... "Olyhater"
:p
It is KAC's opinion that a bolt that does not need an extractor spring replacement every 3000 rounds and a min life cycle of 20,000 rounds is better. The non compatability issue is what would have to be considered by the user.
I too think Rob's chart is a great thing but you will not find us publicly disclosing materials used for bbls or bolts just a estimated life cycle.
I read the link posted in the OLY arms thread concerning Oly Arms response to Rob_S. I hadn't seen that before.
It, and Grant's milspec thread, got me thinking about milspec re: how do we know what is "above" milspec.
The oly arms letter claimed that chrome lining and a different barrel steel made for a better rifle than military specifications. It got me thinking; If milspec is the lowest accepted standards how do we, the laymen, gauge what WOULD make for a better than milspec rifle?
I understand the opinion around here is knight's is considered beyond milspec. So what are they doing that is going beyond?
What is a better barrel steel? What is a better FSP? what is a better x? etc.etc. on down the milspec list.
Any thoughts? Is there a reference or "chart" that contains and discusses the options that would be BETTER or BEYOND milspec? What combination of materials would make a "better than" milspec rifle?
Very good question. It is VERY hard to actually PROVE that you are going above the mil-standard. The best way would be to do it with durability tests in batches of 10 or more (not one gun).
In the case of the SR15, the IWS system is the real improvement in the system I think. Bolt wear/life span is one of the real weak points with the weapon.
Some simple ways to improve the AR:
Better bolt steel
XRAY bolt and barrel (no HP/MP)
Better magazines (we are getting there now)
One could argue that a piston would would enhance the reliability of the weapon. I am hesitant to say that though as there are a lot of piston's out there and very few are quality I think.
C4
You guys are having an OLY SUCKS thread without me??? .... the president of the Oly Haters society???
I remember when that moron from OLY cried to the staff on TOS about my account name.... "Olyhater"
:p
Yep: https://www.m4carbine.net/showthread.php?t=25452&page=2
C4
What it really comes down to is standards, or lack thereof. Do you really want a weapon (or any other kit for that matter) that cannot meet the bare minimum? Some people are happy with that alot of others are not. I am sure that almost everyone here can tell a horror story about something that they bought that was almost as good as what they really wanted only to have it break, or not perform as expected.
I agree with Grants' last statement as well. It is difficult to prove that you are going beyond or improving on the MILSPEC, but it becomes painfully obvious when you don't even meet the bare minimum.
I would say that even with Xray you should still HPT first.
HPT is the equalent of driving a new car into a brick wall and checking the frame for damage. The reality is all bolts will eventually fail. Before they break they crack. You guys would be amazed at how many of your trusted weapons have microscopic cracks in the bolts. I would much rather see a periodic MPI on all fielded weapons at known round intervals than just when the gun leaves the factory. That way we would know when a bolt was ready for replacement before it breaks. The first step to this would be keeping an accurate round count . This has proven to be impossible. Cars have odometers ; we need an equivilent for our service rifles.
RogerinTPA
01-30-09, 13:08
Agreed. A shot counter (Electric or mechanical impulse) like SOCOM has been trying to develop or have developed, would be ideal.
Good responses. I have nothing to add as this is out of my lane. I simply wanted to get a conversation started since the "milspec" argument keeps coming up.
Grant brought up further or better testing and magazines. KAC's representative brought up an odometer type gadget, periodic testing of parts, and perhaps their bolt proprietary bolt and barrel materials. Good ideas.
Anything else?
Heavy Metal
01-30-09, 16:10
One question I would like a definitive answer too is the exact mechanism that causes bolts to fail at such a lower round count in the carbine length gas system weapons that it does in the rifle length gas system weapons.
I have heard two basic hypothesis:
1) A rebound standing-wave type phenomenon that causes the lugs to become momentailry re-loded when unlocking is in progress.
2) Residual chamber pressure that still remains when unlocking commences.
the current spec was developed in large part by real-life combat "testing." The platform was new in vitnam, and went through a lot of changes over the first few years to adjust for failures that were being reported in the field. those test conditions are hard to duplicate. and it's hard to trust anything less than that.
for what it's worth to add.
Outside of using tougher steels, there's not much you can do to the bolt. LMT makes their enhanced bolt, but the extractor has the same amount of rim contact and there has been no quantitative data that I know of that indicates that it is any more durable than a standard bolt. The best idea would be to go to a different bolt design, but then it wouldn't be an AR anymore. Also, with the SCAR and ACR/Masada both using AR-style bolts, we're going to be stuck with them for a while.
That said, in my opinion, feed malfunctions and extraction issues are bigger problems than bolt breakage as they are reliability issues versus durability issues. Granted, new magazines such as PMags and properly sized 5.56 Nato chambers go a long way towards eliminating those issues, but they still exist. The fact of the matter is that the magazine design of the AR is a weak point. There's no way around it. At this point, designing a magazine that locks at the front and rear is not going to happen. I think it really says something that in the government tests, the HK G36 had the least malfunctions over the 416, SCAR, and M4.
Also, enlarging the extractor of the AR bolt would be impossible without further weakening of the design.
I think that we've made the AR about as reliable as it's ever going to be with bandaid fixes such as o-rings, 5-coil extractor springs, heavy buffers, PMags, etc. Maybe what we should be looking at is learning from the lessons of the M16/M4 and getting further away from the design than the SCAR does for future weapons. A front and rear locking magazine, more durable bolt design with larger extractor, and piston operation would be good places to start.
Heavy Metal
01-30-09, 17:19
LMT makes their enhanced bolt, but the extractor has the same amount of rim contact and there has been no quantitative data that I know of that indicates that it is any more durable than a standard bolt.
It is a different design. It is also a higher grade of steel as per Bill Alexander.
It was designed to work in conjunction with the enhanced carrier which provides more gas dumping and an increased delay in the cam timing prior to bolt opening.
That said, there are individuals who have put mover 20,000 rounds on these bollts and to add I have never seen one reoprt of one breaking.
Razorhunter
01-30-09, 17:56
Interesting subject. I'm stoked to see III from KAC participating in this thread, with good info.
That said, anyone care to comment on the following questions?
1. What currently produced AR's on the market, are offered with CHF bbls?
IIRC, the Noveske N4 light bbls are HF or CHF, right? These are the only ones I
know of. ??? Any other HF/CHF bbl'd AR's being sold currently?
2. How about the Colt 6920/BCM/LMT bbls? What bbl steel do these M4's/AR's use? Are they all 4150?
3. Anyone care to comment on Noveskes bbls with the "heavy chrome lining" as used on the SAW? or whatever machine gun it is? Does this "heavy chrome lining" that is thicker than regular CL'ing, add major lifetime to the bbl? Anyone got an estimate on the round count, as compared to say, a Colt or LMT bbl?
4. Anyone care to comment on LWRC's ACB? Has anyone ever posted info on this
bolt, and if/how it improves life expectancy of the bolt?? This is about the only
bolt I've ever had slight interest in, other than my Colt/BCM/LMT bolts...
(Apparently there were SEVERAL different generations of the ACB, not sure
how many though, or what the current model looks like)
We have run our SR-16 bolts to 50k rounds. We use HF CL bbls in all of our 5.56 guns except our match rifles. A full curved mag does not have to cam in. We used modified stoner 63 mags in both of our SCAR submission guns and we use a full curve straight drop mag in our PDW.
Razorhunter
01-30-09, 20:36
Could someone explain to me what the following quote meant, which was posted by III up above in his first post???
"We all know that the non-full curve magazine is a weak link"
What does "non full curve" magazine mean, and why is it bad/weak?
Does "non full curve" mean as opposed to a "full curve magazine"??? What would an example of a "full curve magazine" be??
Never heard this before...
The original AR-10 was designed for a 20 round mag only. It was also one of the first guns to be designed to be made from machined aluminum which also was part of the reason for the straight mag well. The original AR-15 was also designed for a 20 round mag. In fact the mags (made from inexpensive alum.) were designed to be disposable and packaged in ammo cans , that is where the straight mag came from. If you notice all other guns that have a 30 round mag they are full curved (no straight part at the top). This is because these tapered rounds naturally lay out in a full curved pattern. There is a slight binding that occurs when the rounds go from the curved to the straight part of the mag. This intended cheap disposable mag issue also caused the mag well to be designed in such a way that does not permit a thicker more robust polymer mag (like the AUG,SIG,HK) . New polymers have certainly changed things somewhat . I think Magpul is capitalizing on this type of a design. They also did there best to curve the mag as much as possible. The thing about plastics is you never know how they will deteriorate over time .
Good stuff III and on the money. Thanks for sharing.
C4
Razorhunter
01-31-09, 10:59
Ah yes, ok III, I totally understood what a "full curve" magazine is, as compared to a straight 20rd mag, but I admit I did not know this was ever considered to be a weak or "weakER" point, or any issue at all in the AR system.
Has anyone ever attempted to re-engineer the magwell on an AR, in an effort to allow it to accept thicker walled mags? IF this was an issue, I would think someone would have done this long ago, successfully.
Thanks.
Sttrongbow
01-31-09, 12:13
FWIW, the Lancer L5 mag is advertised as having a "constant curve" interior geometry. I have yet to have a mag failure with my 7 L5's. Good mags so far (though I have to file down the mag well lip on them to make them work better in mag pouches)
FWIW, the Lancer L5 mag is advertised as having a "constant curve" interior geometry. I have yet to have a mag failure with my 7 L5's. Good mags so far (though I have to file down the mag well lip on them to make them work better in mag pouches)
To continue the hijack, that lip will be gone on future magazines. Their 20s already come without it.
You guys are having an OLY SUCKS thread without me??? .... the president of the Oly Haters society???
I remember when that moron from OLY cried to the staff on TOS about my account name.... "Olyhater"
:p
While a member of 1SFG I bought an Oly "alphabet gun" since they were down the road. WHAT A POS! Damn thing wouldn't chamber a round. ALL round types, mags, caused EVERY round to get stuck on the feedramps. The morons said 'We test fired it no problems". Told them to shove it, and got my money back.. OLY IS ONLY GOOD TO GIVE TO THE DERKA-DERKAS or FRENCHIES!
Ah yes, ok III, I totally understood what a "full curve" magazine is, as compared to a straight 20rd mag, but I admit I did not know this was ever considered to be a weak or "weakER" point, or any issue at all in the AR system.
Has anyone ever attempted to re-engineer the magwell on an AR, in an effort to allow it to accept thicker walled mags? IF this was an issue, I would think someone would have done this long ago, successfully.
Thanks.
Paul a AK mag is a full curve magazine. A 30 round standard AR magazine still has the straight portion that inserts into the magwell making it not fully curved.
It is my opinion that HPT will reduce the life span of a bolt. My estimate is 15 to 25%.
MarshallDodge
02-03-09, 16:24
There are certain things that are on the chart that came about due to a quality issue that arose.
Does anybody know why HPT came about?
My guess is that a military contractor made rifles (or carbines) that had a bad bunch of bolts and the way to solve it was to test them all to a standard. Was it the best way? Maybe not, but at least you know that you didn't get a soft bolt.
If an Olympic or Bushmaster won't run it probably isn't because they didn't use a certain barrel steel or HP tested it, it's more likely that there is something else out of spec. If they cut corners in one area then they will probably cut them in other areas as well. A crooked bolt isn't going to work no matter how many times you HPT it.
It is my opinion that HPT will reduce the life span of a bolt. My estimate is 15 to 25%.
but whats the trade-off between knowing it's not going to blow in the first 1,000 rounds? the pill might reduce life of an otherwise healthy bolt, but does removing the ones with birth-defects bring the total average up much? how many bolts get black-bagged on the HPT line?
Heavy Metal
02-03-09, 20:31
It is my opinion that HPT will reduce the life span of a bolt. My estimate is 15 to 25%.
Bill Alexander postulated something similar and I agree with him.
I do not believe HPT on an otherwise quality bolt is desirable beyond a batch test.
I am more concerned with whether a bolt was chilled-shot peened.
AFAIK, no bottom feeders CSP their bolts.
Funny you should mention Bill Alexander . I had the good fortune of meeting Bill for the first time and it was a long conversation about bolt proofing that made me feel comfortable making the statement I made above about HPT. I was really impressed with Bill's engineering knowledge and he shared some great thoughts with me. I don't know much about Alexander Arms or their products but after talking to Bill I would certainly buy product from him without hesitation. Just another example of a bright guy out here doing his thing in the AR world. Perhaps there is hope for the future of small arms after all.
III,
Do you have any thoughts on Armalite's patented deprecated lug design for their bolt?
Not familial with it. I have seen LMTs design and understand how it can be beneficial ; esp because it uses a standard bbl extension. Mark Westrom is certainly another guy that is committed to making a difference. I havn't all ways liked Armalite's marketing methods but I can't say anything bad about Mr. Westrom and I respect him a great deal .
My understanding is, Armalite's engineering analysis predicts (maybe proves???) that the assymetric lug design on the AR's bolt results in a disproportionate loading on the two lugs adjacent to the extractor cutout, and it's because of this higher loading that lug failure almost always occurs on either of these two lugs.
What Armalite does is, they shorten the lug opposite the extractor to the point where it's no longer load bearing. What this does is change the loading pattern from two heavily loaded lugs plus five lightly loaded lugs to six symetrically spaced, evenly loaded lugs, with each having significantly less loading than the two heavily loaded lugs in a conventional design.
Sounded interesting to me, but Armalite is one of those brands where you never hear much anecdotal evidence one way or another to compare observed results with modelling/theory.
but whats the trade-off between knowing it's not going to blow in the first 1,000 rounds? the pill might reduce life of an otherwise healthy bolt, but does removing the ones with birth-defects bring the total average up much? how many bolts get black-bagged on the HPT line?
III on this note.
If HPT is part of milspec, and we are all of the opinion that milspec is the lowest common denominator thus one does not want to ever go below it, how would the industry qualify bypassing it?
When I first read your post about HPT and the reducing of life, I thought along the same lines as the above quote.
Now, when dealing with quality companies such as Knights, LMT, colt, noveske etc. I would be ok with bypassing it due to the respected records and history of service.
Like someone else asked, when did HPT come about? Why did it come about?
Thanks again for all the information in this thread.
Any other industry professional or SME, designated or not, feel free to chime in on the questions.
It is my opinion that HPT will reduce the life span of a bolt. My estimate is 15 to 25%.
Its funny well not so much but I had a fully tested bolt arrive from one of our go bolt companies and it arrived with a nice crack in it. Said company of course made good on it but it just goes to show nothing is perfect.
III on this note.
If HPT is part of milspec, and we are all of the opinion that milspec is the lowest common denominator thus one does not want to ever go below it, how would the industry qualify bypassing it?
When I first read your post about HPT and the reducing of life, I thought along the same lines as the above quote.
Now, when dealing with quality companies such as Knights, LMT, colt, noveske etc. I would be ok with bypassing it due to the respected records and history of service.
Like someone else asked, when did HPT come about? Why did it come about?
Thanks again for all the information in this thread.
Any other industry professional or SME, designated or not, feel free to chime in on the questions.
One of they ways for a manufacturer to bypass the TDP on bolt reqs, would be to XRAY the steel. This is a superior method to HPT/MPing them.
C4
One of they ways for a manufacturer to bypass the TDP on bolt reqs, would be to XRAY the steel. This is a superior method to HPT/MPing them.
C4
I assume less stressful was well therefor bypassing III concerns of shorting bolt life. Is this correct?
I assume less stressful was well therefor bypassing III concerns of shorting bolt life. Is this correct?
The theory is that by HP testing something, you are removing one of its lives. Now the question is, how many lives does the barrel or bolt have in it? No one knows this for certain.
I was told by someone that HP's barrels on a regular basic (and uses the same bolt) that the bolt has hundreds of proofs on it and is still going strong. This particular bolt might be the exception and any other bolt might only take 2-3 high pressure loads (again no on knows).
I was watching How Its Made last night and they were building icebreakers. They showed them doing a test where they tie the boat to shore and basically run the engines at full power for 6 hours! They said the purpose of this was to make sure everything stayed in place and nothing went wrong (basically stress testing it).
So IMHO, until companies XRAY their steel, HPing and MPing is still the best option we have to stress the system and find any faults.
C4
We do not HPT all SR-25 bolts and we don't HPT any SR-15/16 bolts but in the 10 or so years that we have produced the SR-25 we have had 0 failures of bolts from HPT. It is hard to justify a process as expensive as HPT when you have this sort of failure rate . My dad and I had a discussion on the reduction of bolt life issue due to HPT and he agreed to let me do a test so stayed tuned to this issue I do not really have enough data to support the statement " HPT will reduce bolt life". I do think this is a important subject for discussion . I would love to hear another mfg. report on failure rate due to HPT.
Isn't it HPT and then MPI to find the cracks?
I can think of two tests that would be interesting, but am not sure how many bolts you would have to use to make it statistically significant.
The first would be simply to HPT one batch of bolts, NOT HPT another, and then MPI all of them and check the failure rate.
The second would be to HPT one batch of bolts, NOT HPT another, and shoot the bolts to failure.
I don't think the second test would be very feasible just due to logistics and ammo costs.
FWIW, last time I checked neither BCM or Noveske HPT'd their bolts and only MPI.
If you need any help running the second test, I can be there in two hours or so. :D
We do not HPT all SR-25 bolts and we don't HPT any SR-15/16 bolts but in the 10 or so years that we have produced the SR-25 we have had 0 failures of bolts from HPT. It is hard to justify a process as expensive as HPT when you have this sort of failure rate . My dad and I had a discussion on the reduction of bolt life issue due to HPT and he agreed to let me do a test so stayed tuned to this issue I do not really have enough data to support the statement " HPT will reduce bolt life". I do think this is a important subject for discussion . I would love to hear another mfg. report on failure rate due to HPT.
I have talked to a couple manufacturers that HPT and MP and they tell me that they see around 2-3% failure rate.
The biggest variable that is not being discussed here is what the acceptance criteria is. Meaning different companies allow different things. Some companies have a ZERO acceptance policy. No cracks of any kind are allowable. Other companies do not have this policy.
I look forward to hearing about your test!
C4
Isn't it HPT and then MPI to find the cracks?
I can think of two tests that would be interesting, but am not sure how many bolts you would have to use to make it statistically significant.
The first would be simply to HPT one batch of bolts, NOT HPT another, and then MPI all of them and check the failure rate.
The second would be to HPT one batch of bolts, NOT HPT another, and shoot the bolts to failure.
I don't think the second test would be very feasible just due to logistics and ammo costs.
FWIW, last time I checked neither BCM or Noveske HPT'd their bolts and only MPI.
If you need any help running the second test, I can be there in two hours or so. :D
BCM HPT's their bolts.
C4
Very informative thread. Is it safe to say that in 2009 an M4-series carbine is as mechanically reliable and has comparable longevity to an M16-series rifle?
Very informative thread. Is it safe to say that in 2009 an M4-series carbine is as mechanically reliable and has comparable longevity to an M16-series rifle?
I would not say that. Reason is that the rifle length gas system is very soft shooting.
C4
TheGhostRider
02-07-09, 09:03
Regarding Mil-Spec...
To me personally, the most important part of the Mil-Spec is the Quality Control of the assembly process.
You can take the highest quality parts available, carelessly assemble them and have an unreliable gun. No parts break... the gun just doesn't run smooth or at all.
You can take low quality parts, carefully assemble them and have a gun that functions good but breaks parts all the time... it's hindrance is the poor quality of the machining of small parts (dimensional variances) or improper heat treating of the steel causing softness or brittleness or a combination of the two, any of which can lead to component failure... sometimes in a violent fashion leading to injury or worse.
The worst part of these scenario's is the number of people who do one or the other scenario on a daily basis and refuse to listen to the advice of the truly knowledgeable when their shit doesn't run.
Or the guy who bought a factory gun of "lesser quality" and gets butt hurt when he's told the truth why his shit doesn't run.
Take components of known good/excellent quality, assemble them properly and you'll have a winner every time.
Buy a factory built gun by a known quality manufacturer and most likely you'll never have to look back and question your purchase.
Just remember... even the quality maker’s puke a lemon out the door once in awhile. ARs are machine's... just like cars. ARs are made by humans, operated by humans; human error will always be a factor in the manufacture of guns and their parts just like cars.
The Mil-Spec is a basic guideline regarding the manufacture and assembly of parts of all types; not just for guns. It should be viewed as the "minimum standard" for manufacturing. There is no "maximum standard"; the parts either meet the spec or they don't.
There should be no reason not to make/assemble them better than the spec requires.
Jay Cunningham
02-07-09, 09:08
Regarding Mil-Spec...
To me personally, the most important part of the Mil-Spec is the Quality Control of the assembly process.
You can take the highest quality parts available, carelessly assemble them and have an unreliable gun. No parts break... the gun just doesn't run smooth or at all.
You can take low quality parts, carefully assemble them and have a gun that functions good but breaks parts all the time... it's hindrance is the poor quality of the machining of small parts (dimensional variances) or improper heat treating of the steel causing softness or brittleness or a combination of the two, any of which can lead to component failure... sometimes in a violent fashion leading to injury or worse.
The worst part of these scenario's is the number of people who do one or the other scenario on a daily basis and refuse to listen to the advice of the truly knowledgeable when their shit doesn't run.
Or the guy who bought a factory gun of "lesser quality" and gets butt hurt when he's told the truth why his shit doesn't run.
Take components of known good/excellent quality, assemble them properly and you'll have a winner every time.
Buy a factory built gun by a known quality manufacturer and most likely you'll never have to look back and question your purchase.
Just remember... even the quality maker’s puke a lemon out the door once in awhile. ARs are machine's... just like cars. ARs are made by humans, operated by humans; human error will always be a factor in the manufacture of guns and their parts just like cars.
The Mil-Spec is a basic guideline regarding the manufacture and assembly of parts of all types; not just for guns. It should be viewed as the "minimum standard" for manufacturing. There is no "maximum standard"; the parts either meet the spec or they don't.
There should be no reason not to make/assemble them better than the spec requires.
Well said. There are certain QC steps on the Colt production line that, if not met, will actually shut the whole line down. Think this was Colt's idea? Nope, but the .gov mandated it and Colt must comply to keep the contract.
BCM HPT's their bolts.
C4
It is not listed and the last time I asked Paul he said they did not
source (http://www.bravocompanyusa.com/BCM-AR15-Bolt-Assembly-MPI-p/bcm%20bolt%20assemly%20mp.htm)
The bolt assembly is shot peened for increased strength, includes tool steel machined extractor, BCM™ Extractor Spring, and is MPI (Magnetic Partical Inspected).
It is not listed and the last time I asked Paul he said they did not
source (http://www.bravocompanyusa.com/BCM-AR15-Bolt-Assembly-MPI-p/bcm%20bolt%20assemly%20mp.htm)
Correct. He did want to list it as he didn't know if he would be able to always HP them. With them doing more and more barrels (which are HP'd), they have been doing the majority (if not all) their bolts.
C4
Very informative thread. Is it safe to say that in 2009 an M4-series carbine is as mechanically reliable and has comparable longevity to an M16-series rifle?
On alot of the parts no where close.
Sttrongbow
02-08-09, 09:50
My understanding is, Armalite's engineering analysis predicts (maybe proves???) that the assymetric lug design on the AR's bolt results in a disproportionate loading on the two lugs adjacent to the extractor cutout, and it's because of this higher loading that lug failure almost always occurs on either of these two lugs.
What Armalite does is, they shorten the lug opposite the extractor to the point where it's no longer load bearing. What this does is change the loading pattern from two heavily loaded lugs plus five lightly loaded lugs to six symetrically spaced, evenly loaded lugs, with each having significantly less loading than the two heavily loaded lugs in a conventional design.
Sounded interesting to me, but Armalite is one of those brands where you never hear much anecdotal evidence one way or another to compare observed results with modelling/theory.
From an engineering point of view, it makes sense. You want to distribute load as much as possible. I'm curious as to whether this plays out in real world evidence.
Sttrongbow
02-08-09, 10:05
The theory is that by HP testing something, you are removing one of its lives. Now the question is, how many lives does the barrel or bolt have in it? No one knows this for certain.
C4
Exactly Grant. If you do an relaibility analysis, virtually all parts follow a "bathtub curve" for failures. There are a high number of failures early, then relatively few for the majority of the life of the part, then a high number of failures at the end of the part's life. These early failures are referred to (rather morbidy) as "infant mortality". For companies who are very concerned with reliability, you want to try and deal with those early "infant" deaths. One way, of course, is to try and refine the design and process of manufacturing to reduce such defects (which are usually attributed to faults in materials or manufacturing processes, or BIG design flaws). Another is to inspect the hell out of them.
But the last, is to ship the part after you've clipped off a big portion of the left hand side of the "bath tub." Computer companies, for example, "burn in" their computers to reduce those early failures. This sort of HPT testing does the same thing, but in an accelerated fasion. 25% reduced life? I'm not sure about that. III has tons more experience with ARs than I do, but as I understand it, late failure in AR15 bolts are mainly due to fatigue at the locking lugs. Early failures exposed by HPT would be mainly due to poor hardening, or faults in the material.
But although a mechanical engineer... I am very new to the AR world. This is a fascinating discussion.
but as I understand it, late failure in AR15 bolts are mainly due to fatigue at the locking lugs. Early failures exposed by HPT would be mainly due to poor hardening, or faults in the material.
just my anecdotal experience and memory here, but aren't most of the late bolt-failures cracks at the cam pin hole? while broken lugs are typically associated with overpressure events?
Bill Alexander
02-08-09, 20:30
The degredation of component life from overload events is well documented and can be supported from a significant number of case studies as well a a wealth of analytical research. It is not a question of does an overload such as a high pressure cartridge reduce the bolt life but rather it is a judgement of how much. The stress concentrations that exist withing the bolt are difficult to characterize exactly as both the loading and the form are complex.
In considering the bolt, the analogy of electronic burn in is not very representative. Correctly the life of a fleet is described by a Guassian distribution curve but an overload event will not in effect remove the early failures and leave only the better units, it acts to shift the whole curve to the left. It will remove defective units from the fleet, but these should be identified from the process data and in most cases, break in of the unit with standard load cycles.
The theoretical foundation for Armalites bolt design is solid and the stress transfer to the two lugs adjacent to the extractor can be argued especially as enough float exists within the AR to allow this to take place. However as both the plane of the lugs and the plane of the barrel extension lugs are maintained to a tight specifications, then the gain in the real world must be considered in the light of the removal of +14% of the load bearing members. Those familiar with the LMT bolt will note that a different approach is to add a greater degree of elasticity to the lug plane and thus allow the lugs to all share the load evenly.
Agressive chemicals used for cleaning and/or a less than true receiever will probably have more influence on the bolt life.
Cam pin hole failures can ususally be traced to the swaging on the bottom of the cam pin hole, which initiates the crack. Cam pins moving under the leverage of the cam path will effectively bend the bolt and diagnosis of the fault in failed parts is easy to see from two bright spots at the top and bottom of the cam pin hole. Cam pins should be replaced when wear is seen on the surface and when they become loose in the bolt.
Bill Alexander
Sttrongbow
02-09-09, 06:08
Mr Alexander,
Thank you for your excellent analysis!
I did not mean to suggest that bolt life is not shortened by the HPT, just that I thought 25% seems intuitively high to me. But like I said, I am new to the AR, so I could very well be wrong.
Also, you did a much better job describing my thoughts on how HPT could weed out the bad bolts early.
I have one question: If failures of the bolt at teh cam pin hole can be traced to a particular spot, is there an inspection would could identify the the ones likely to fail early?
Again, thanks for taking to time to educate us here!
The degredation of component life from overload events is well documented and can be supported from a significant number of case studies as well a a wealth of analytical research. It is not a question of does an overload such as a high pressure cartridge reduce the bolt life but rather it is a judgement of how much. The stress concentrations that exist withing the bolt are difficult to characterize exactly as both the loading and the form are complex.
In considering the bolt, the analogy of electronic burn in is not very representative. Correctly the life of a fleet is described by a Guassian distribution curve but an overload event will not in effect remove the early failures and leave only the better units, it acts to shift the whole curve to the left. It will remove defective units from the fleet, but these should be identified from the process data and in most cases, break in of the unit with standard load cycles.
The theoretical foundation for Armalites bolt design is solid and the stress transfer to the two lugs adjacent to the extractor can be argued especially as enough float exists within the AR to allow this to take place. However as both the plane of the lugs and the plane of the barrel extension lugs are maintained to a tight specifications, then the gain in the real world must be considered in the light of the removal of +14% of the load bearing members. Those familiar with the LMT bolt will note that a different approach is to add a greater degree of elasticity to the lug plane and thus allow the lugs to all share the load evenly.
Agressive chemicals used for cleaning and/or a less than true receiever will probably have more influence on the bolt life.
Cam pin hole failures can ususally be traced to the swaging on the bottom of the cam pin hole, which initiates the crack. Cam pins moving under the leverage of the cam path will effectively bend the bolt and diagnosis of the fault in failed parts is easy to see from two bright spots at the top and bottom of the cam pin hole. Cam pins should be replaced when wear is seen on the surface and when they become loose in the bolt.
Bill Alexander
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