View Full Version : FailZero and supressors...
To clarify from the beginning, this is NOT a complaint thread. Just observations.
As many of you know, we in Washington state finally had the law changed so that we may actually use our legally owned supressors.
In celebration of this, several large supressor shoots were held in various locations around the state. I attended the one on the Kitsap peninsula with my M4 "frankenabortion", Gemtech M4-96D, Beretta 92fs and Gemtech G9.
For this shoot, I installed a recently aquited FZ complete BCG, and hadn't cleaned or lubed the rifle for approx 500 rounds. of non-supressor shooting prior.
During the 2 hours I was there, a friend and I fired approximatly 600 rounds through the rifle, all suppressed, and ended up carbon welding the supressor to the bi-lock. I was unable to remove the supressor at the range, and took it home for cleaning.
Info: The rifle is a Stag/CMT upper, lower, FCG, reciever extension, and buffer, a Bushhamster M4 barrel (1/9) 14.5 inch with permanently attached bi-lock. This rifle has approx 8000 to 10000 rounds down the pipe,most semi, some (somewhere around 1000 to 2000 rounds) FA on the upper receiver only as I loaned it to a local type 7 SOT for some shooting several times(also the reason for the approximation of the round count).
Issues: had 5 failures to lock back on the last round. Three times were with my friend who was there with me and was with his ammunition and magazines. Ammo was Bvac bulk, and the magazines were two FDE Pmags and a single USGI aluminum. I experienced two similar situations with USGI Okay brand magazines. All malfunctions took place near the end of our shooting session, and were followed by several other magazines that locked back the BCG just fine. Other then that, it ran like a top. By this point, the rifle was hot enough that it was too hot to touch even the upper reciever much less the barrel or the can. As it were, the can was putting off so much heat that it was causing visual interferrence in sighting on the targets.
Observations: Gun was filthy as a 3 dollar whore after a three day weekend with no shower. Hand cycling the rifle felt gritty as a gravel road. Was able to remove the M4-96D by hammering it off with a derlin armorers block, a fair amount of solvent, and lots of elbow grease.
After disassembly, I noticed several impacts on the circumference of the buffer that matched up perfectly in shape to the buffer retainer pin. This is brand new wear, never seen before. Doesn't affect function though. Makes me wonder if the carrier may have been machined just a tad too short and is allowing the buffer to come too far forward and impact the buffer retainer pin. Dissapointing if true.
About the FZ BCG: I had read many review claiming that fouling simply wipes off and cleaning baked on carbon buildup from the rear of the bolt was super easy. I found none of this to be true.
I had to scrub the crap out of the BCG, and it still won't get completely cleaned. As in it looks like the entire BCG is stained so it's a kind of gunmetal grey color. Scraping carbon from the end of the bolt required just as much work as before on the non NB BCG that was in it previous.
The rest of the rifle took far longer to clean then normal due to excessinve carbon buildup, but I expected this so it's no big deal. Some caked on fouling in the upper had to be removed with a brass brush because the plastic mil-issue cleaning kit brush simply wouldn't touch it. Cleaner used was Lucas feul injector cleaner. I've been using this for awhile because it simply eats away carbon as that is what it's job is on engine valves and it works great on guns and is way less smelly then most gun cleaning solvents. Works best if applied and let sit for a little bit. It will creep and soak into fouling and break it up.
Conclusions: Frankly, I don't care about the new, non super-silver color of the BCG. It was too shiny in my opinion to begin with. Now it just looks like a heavily worn standard BCG. No big deal especially considering that it still feel just as slick now as it did when new and continued working under those conditions. As advertised, none of the NB flaked off or was worn off, just discolored.
Insofar as the failures to lock back, because the rifle continued to work fine after those incidents and locked back on several more magazines and the brass ejection remained consistent throughout the shooting session, I really have no idea what caused the issues. Could be shitty ammo that my friend supplied ( he supplied all of the ammunition we shot that day) some excessive carbon buildup somewhere, etc. My bet is on the heavy fouling and lack of lube. as the ammo was ejecting very consistently during the shoot whenever observed.
I checked the buffer roll pin to see if it was working it's way out and binding on the buffer spring and found it to be fine. Carrier key was plenty tight and staked properly. Gas rings were all brand new at the beginning of the shoot.
Weapon was cleaned and lubed with marine wheel bearing grease, and after dealing with a family thing this morning, a return to the range resulted in the following: Rifle function fine unsupressed and supressed through 8 magazines with zero issues. After verifying zero with the can, was hitting an 8 inch steel plate at 150 yards shooting approx 1 round per second and hitting every round out of a complete magazine. Shooting done from the bench.
My prognosis is that the FZ BCG *can* be run dry under "normal" conditions, even in some difficult conditions, but even it will have minor issues when all lube is burned off, the gun is frikken filthy, and being run with a supressor. To be honest, I believe that with the original BCG in place, the gun would have failed much much earlier considering how dirty it was. As noted earlier, when cleaned, I lubed like I normally do. Just because the FZ BCG *can* be run dry, doesn't mean that it *should* be. All moving metal parts work better with lube no matter what they are made from or coated with.
Final FYI: This rifle is a build of my own. In those 8 to 10K rounds it has down the pipe, I have not had a single failure caused by the gun previous to this. This is a beater rifle and gets used regularly in training where it has been subjected to shitty weather conditions, mud, extreme fouling, etc. and it runs like a typewriter. Truly is my go-to gun and after it proved itself, I would take this over a new Colt any day of the week simply because I know it works no matter what.
post script: The most difficult part to clean was the outside of the supressor and the end of the barrel. After shooting his first few magazines, my friend laid the rifle down on the carpet covered bench without thinking and melted a bunch of the nylon carpeting to the supressor and barrel. Was a ****ing bear to remove. I didn't make him clean it because he supplied the ammo for the days festivities.
PatrolRifleGroup
07-25-11, 05:39
I have two of the FZ BCG's. I have learned over time, that the "Wipes clean after shooting" statement, is only true if you run the gun wet. If you run a FZ dry and allow the carbon to bake on, you might as well bust out the dental picks and scour pads.
Apricotshot
07-25-11, 07:29
post script: The most difficult part to clean was the outside of the supressor and the end of the barrel. After shooting his first few magazines, my friend laid the rifle down on the carpet covered bench without thinking and melted a bunch of the nylon carpeting to the supressor and barrel. Was a ****ing bear to remove. I didn't make him clean it because he supplied the ammo for the days festivities.
Same thing happened to me with my first 556 can. I ended up just dumping a few mags through it next time I was out and wiping the melted carptet off with a couple shop rags.
The reason that the bolt didn't lock back on the last round is most likely do to the fact that the BCG is going to fast. BM barrels are WAAAAY over gassed. Then you couple that with a suppressor (which basically doubles the amount of pressure) and you have a really fast moving BCG.
I don't think you mentioned what buffer and spring you are using, but I would go with an H3 and a RED Tactical Spring Co CS buffer spring. This will slow things down a bit.
All BCG's need cleaned and lubed (no matter the finish). So when you had about 500rds in the gun, that would have been a good time.
It is true that some finishes will allow you to get away with this for longer, but at the end of the day, you aren't doing yourself any favors (which you found out).
C4
I've found that after a few hundred rnds the carbon does wipe off my FZ bcg except the bolt tail but to this point it has scraped off rather easily
Even before I bought the FZ carrier, I figured that "wipes clean with just a rag" really means "wipes cleaner with just a rag" and I haven't been disappointed. If you want to keep your weapon free of carbon fouling, it's easier if you do a lot of little cleanings than one big one
600 rounds of supressed fire is a tall order for any gun. A malf here and there should be expected with that kind of heat and filth.
In addition to what Grant stated, I can tell you for a fact that a Bushmaster barrel with that many rounds through it has a gas port the size of Venessa Del Rio's hole. I was examining gas ports a couple of years back in BM carbines that probably had less than that through them and the port was "egged" out.
Add the suppressor to it and you're getting a shitload of gas through that thing.
600 rounds of supressed fire is a tall order for any gun. A malf here and there should be expected with that kind of heat and filth.
Legal can use in WA state is still pretty new, and there are a lot of people that are going to be fine tuning things for awhile. Blow back, heavy cleaning regiments, and baffle strikes are things that are going to suddenly start popping up in circles where there weren't previously any issues.
TonyTacoma
07-25-11, 13:55
I can't wait to get an osprey for my fnp tactical, now we just need to get SBR's legal here in Washington. I think there will be a learning curve for us though, although I think there are quite a few guys that we're shooting suppressed long before it was legal.
although I think there are quite a few guys that we're shooting suppressed long before it was legal.
I know I would have been. :)
I know I would have been. :)
It's for the children. Wouldn't want them to get hearing loss from being near the guns.
I think there will be a learning curve for us though, although I think there are quite a few guys that we're shooting suppressed long before it was legal.
Agreed, and you can tell the stupid ones as they brag about it.
I take a slight issue with this statement. I used to live in Washington state. And though I agree the law was stupid and poorly written, I knew people who shot their suppressors OUTSIDE of Washington in Oregon and Idaho.
So it's not necessarily true that people were doing in within the state of Washington.
I can't wait to get an osprey for my fnp tactical, now we just need to get SBR's legal here in Washington. I think there will be a learning curve for us though, although I think there are quite a few guys that we're shooting suppressed long before it was legal.
TonyTacoma
07-25-11, 17:27
I take a slight issue with this statement. I used to live in Washington state. And though I agree the law was stupid and poorly written, I knew people who shot their suppressors OUTSIDE of Washington in Oregon and Idaho.
So it's not necessarily true that people were doing in within the state of Washington.
Iraq I think you may have misinterpreted what I was saying a bit. Im not saying everyone who owned one shot it illegally, just that there were A LOT of people who did.
Grant: Forgot the buffer specs. Standard carbine spring and H2 buffer. An extra tidbit of info: The BCG that FZ used is a Toolcraft Inc. setup which, if I remember the thread here on M4C, they are an FN contractor.
Insofar as being over gassed, I generally keep a good eye on the ejection patterns so as to know when spring maintinence needs to take place. This rifle has always ejected to about the 3:30/4:30 position unsupressed (still did this weekend when tested without the supressor and clean), and to about the 2;00/2:30 supressed. Nothing was amiss ejection wise during the shoots this weekend. Not sure if it was bolt speed, filth, or something else that caused the failures. If it were bolt speed, I would suspect that the issue would be worse once the gun is cleaned and lubed properly, but that wasn't the case.
I wouldn't be suprised if the gas port is a bit excessive at this point as IG points out, although like I mentioned, I haven't had any over gas issues with the rifle prior to this. I regularly maintinence the rifle and change springs sometimes even before I figure there will be an issue simply because this is my "go to" rifle. This means that I regularly
have all the springs up to spec and the rifle hasn't shown any change in behavior that might be caused by excessive gas port issues as time goes by and all things are returned to spec.
All of that being said, given the extremes of the situation and that the rifle continued to function despite the filth of the previous 500 rounds and the additional 600 supressed (which as MarkM pointed out is a tall order for a rifle under normal contitions), and the fact that it continued to run perfectly again after cleaning, I must say that i'm quite happy with FZ products so far and would reccomend them to anybody.
FYI post script:
For what it's worth, I have family in Oregon(my home state as well, born and raised there, still trying to figure out why I was dumb enough to leave) and have plenty of rounds through the can during visits, I have just never run it this many rounds prior to cleaning the rifle.. I bought the can used with no waranty (and it's prior owner bought it as a factory blemished can for cheaper then normal) and treat it as a "beater" item just like the rifle. I even stopped keeping track of it's round count at this point. I'll just shoot it until it fails and then replace it. It also already has a couple of minor baffle strikes but don't really care as it still sounds the same as a virtually new M4-96D owned by a friend when shot side by side.
The can has also cracked the laser weld between the mounting software and the main body of the can, and there is even a very slight buldge around the circumference of the supressor up near the endcap (cause unknown). Since it's not under waranty, I'll just keep shooting the hell out of it. The buldge hasn't gotten any worse in the last 2k rounds shot through it. Despite all of these *issues*, it runs great and still works fine so I frankly don't care..
I have run the supressor pretty hard before, although never to the tune of 600 rounds at a shot, and i've even had it so hot once(took about 200 rounds in semi) that it was glowing red and you could tell where the baffles were inside by the slightly darker rings in the red, yet it has never failed to do what it's supposed to do. Gemtech did right when they made this can.
For the record, the reason for my actions this weekend was to see if the FZ BCG works as advertized rather then a supressor test. I already know that the supressor will work, and that as a whole (with the original BCG, given even sparse maintinence with continued added lube, the rifle will do it's part as well.
Lastly, the charging handle is a PRI gasbuster. I've shoot with it before, just not to this extent. By the end of the session, there was still a fair bit of carbon on my face. Considering some of the stories i've read about PRI gas busters failing under hard use, I'm really considering just going BCM gunfighter and doing the RTV silicone route.
I don't lube my SBR equipped out a FZ BCG simply out of spite. Cleaned mine last night for the first time in just under 3k because I got it to choke after a 500+ round training session on Saturday. Anyway, it takes over 2k rounds before it starts choking out (even though, yes, it feels like it's going to stop any moment when hand cycling). During a shoot last summer when it started failing (it was ~2.5k rounds in since last maintenance) I simply scraped carbon off with a knife and tossed it back in the gun. Ran like a top.
I think the only reason mine chokes after 2k rounds is because it's way overgassed. Legion has a rifle with ~5k rounds through it, no cleaning no lube IIRC but it's a fullsize rifle all FZ'd out and unsuppressed.
Anyway, it's mostly an academic discussion because for normal use, you'll have many opportune times to add a few drops of oil every several hundred rounds. Hence why my, 'fullsize' carbines still run regular old BCG's and not FZ'd ones.
Anyway, it's mostly an academic discussion
Absolutly.
I highly doubt that I will ever be in such a situation that would require the kind of performance that I asked of the rifle this weekend.
I'm kind of goofy like that though. Although I read the reviews of new products and how well some of them work, once I take the step to purchase one, I must test it to know for sure so I do things like what I did this weekend. I like to *know* things rather then simply *think* things.
Thanks all for the interesting replies. Always something to be learned.
GermanSynergy
07-26-11, 01:37
I lube my Fail Zero BCG just as much as a normal one. Lube is cheap and it doesn't hurt anything.
Grant: Forgot the buffer specs. Standard carbine spring and H2 buffer. An extra tidbit of info: The BCG that FZ used is a Toolcraft Inc. setup which, if I remember the thread here on M4C, they are an FN contractor.
I wouldn't be suprised if the gas port is a bit excessive at this point as IG points out, although like I mentioned, I haven't had any over gas issues with the rifle prior to this. I regularly maintinence the rifle and change springs sometimes even before I figure there will be an issue simply because this is my "go to" rifle. This means that I regularly
have all the springs up to spec and the rifle hasn't shown any change in behavior that might be caused by excessive gas port issues as time goes by and all things are returned to spec.
A "bit excessive" is the understatement of the century. Mil-Spec GP size on a 14.5" M4 is .063. Your GP size can be as high is .083!
So while you think your gun is behaving normally, it really isn't. You just don't have a mil-spec gun to reference it to.
C4
A "bit excessive" is the understatement of the century. Mil-Spec GP size on a 14.5" M4 is .063. Your GP size can be as high is .083!
So while you think your gun is behaving normally, it really isn't. You just don't have a mil-spec gun to reference it to.
C4
What would be "behaving normally" compared to how it's acting now?
I was under the impression that the ejection pattern I described is that of a rifle in good working order given proper spec'd springs, headspace, etc.
What am I missing?
What would be "behaving normally" compared to how it's acting now?
I was under the impression that the ejection pattern I described is that of a rifle in good working order given proper spec'd springs, headspace, etc.
What am I missing?
Less recoil, less pressure, less heat, less debry in the chamber, etc.
Ejection patterns are really nothing to pay attention to when trying to identify if your gun is over gassed or not. Measuring the GP size does that.
As far as buffer springs go, we measure those as well. ;)
C4
Less recoil, less pressure, less heat, less debry in the chamber, etc.
So far none of these seem to be an issue. As in I havn't noticed an increase in recoil, never measured it's heat so I have no idea, and the fouling has been consistent thus far.
Ejection patterns are really nothing to pay attention to when trying to identify if your gun is over gassed or not. Measuring the GP size does that.
With any machine, observing "behavioral patterns" is usually how we figure out if a machine is going "out of spec". Given all things being equal (bufer spring is within spec, ejector spring is within spec, extractor is in good condition with proper spring, insert and Crane O ring, gas tube is within spec, Carrier key is fully tightened and staked, the gun headspaces properly, etc.) the gun *should* work within a standard.
To date, the best indicator of this standard is ejection pattern, given all known parts being within spec.
Are you saying this is not the case?
I have always used machinery until its behavior patterns change, then based on those changes, the machine is maintinenced and returned to as close to original operating specs as possible and then put back into use.
To date, this gun has not exhibited any of the issues that comes with an over gassed gun. No excessive BCG speed, fouling is "normal", the buffer is not showing excessive wear on the nylon buffer insert. Recoil spring is within tolerance(replaced less then 2K rounds ago actually).
Once again, what am I missing?
As far as buffer springs go, we measure those as well. ;)
C4
As do I. Been doing it for well over a decade. Been building AR's since 1996 in some form or another. This is nothing new to me. This thread was an observational thread about the FZ BCG, not a trouble shooting thread for my gun. Just because it had a few unexplainable issues that weren't really "big deal" issues to begin with doesn't mean i'm worried about the gun, expecially considering what I had put it through before it started acting like that and the fact that it continues to work properly once cleaned..... ;)
That being said, I would really like to understand exactly how this "over gassed" stuff works. In my experience, gas port erosion starts on the portion of the gas port on the inside of the barrel, and as it grows it starts working its way through the barrel wall towards the gas block.
This being the case, the important dimension here is the size of the gas port on the outside diameter of the barrel where it opens into the gas block. While gas port erosion on the inside diameter of the barrel is primarily where the most damage is done, so long as the exit of the port on the OD of the barrel remains within spec, the amount of gas getting into the system will remain consistent.
I'm getting really tempted to punch off my FSB just to measure now because of all of this.
So far none of these seem to be an issue. As in I havn't noticed an increase in recoil, never measured it's heat so I have no idea, and the fouling has been consistent thus far.
How would you know what is standard and what isn't?? How many mil-spec AR's have you owned?
Since you live in WA, your knowledge about suppressors and how they affect AR's is going to be pretty limited.
You can only notice differences IF you have a good frame of reference.
With any machine, observing "behavioral patterns" is usually how we figure out if a machine is going "out of spec". Given all things being equal (bufer spring is within spec, ejector spring is within spec, extractor is in good condition with proper spring, insert and Crane O ring, gas tube is within spec, Carrier key is fully tightened and staked, the gun headspaces properly, etc.) the gun *should* work within a standard.
To date, the best indicator of this standard is ejection pattern, given all known parts being within spec.
There are SO MANY things that can change the ejection pattern that it really is a waste of time to use this as an identifier of ANYTHING.
Some of the things that will affect this is:
1. Ammo selection.
2. Extractor tension (both the extractor insert and extractor spring).
3. Extractor wear.
4. Buffer weight.
5. Buffer spring tension and length.
Just so you know, NOTHING about your BM is "within spec." BM doesn't follow a set standard. So back again to establishing a known standard.
I have always used machinery until its behavior patterns change, then based on those changes, the machine is maintinenced and returned to as close to original operating specs as possible and then put back into use.
From day one, your "machine" AKA BM AR, has been assembled incorrectly. So if it it all the sudden became "in spec" the difference in it would make you think something is wrong.
To date, this gun has not exhibited any of the issues that comes with an over gassed gun. No excessive BCG speed, fouling is "normal", the buffer is not showing excessive wear on the nylon buffer insert. Recoil spring is within tolerance(replaced less then 2K rounds ago actually).
Really? Are you sure? To start, the amount of carbon build up you have is much greater than if you owned a Colt. The amount of heat and pressure exerted onto the bolt are much higher. So your definitions of "normal" are not the correct version of normal.
You BCG failed to lock back on the last round. That generally means that it is going to fast.
As do I. Been doing it for well over a decade. Been building AR's since 1996 in some form or another. This is nothing new to me. This thread was an observational thread about the FZ BCG, not a trouble shooting thread for my gun. Just because it had a few unexplainable issues that weren't really "big deal" issues to begin with doesn't mean i'm worried about the gun, expecially considering what I had put it through before it started acting like that and the fact that it continues to work properly once cleaned..... ;)
Have any the AR's you have had experience with (for over a decade) been mil-spec? Suppressed?
Having ANY issues with a gun IS an issue, especially if you are going to bet your life on it. So I would be concerned and would be getting to the bottom of these problems REAL QUICK. This is why myself and some of the others have gone to great lengths to explain that your gun is WAY over gassed and then you added a suppressor for good measure (just in case you did not have enough gas in the system).
I can get a lot of crappy AR's to "work." They are far from ideal though and would not use them for anything other than shooting dirt.
That being said, I would really like to understand exactly how this "over gassed" stuff works. In my experience, gas port erosion starts on the portion of the gas port on the inside of the barrel, and as it grows it starts working its way through the barrel wall towards the gas block.
No GP erosion even needs to take place on your gun. You see, BM made sure that your gun had an out of spec GP size from DAY ONE!
It is also true that larger than spec GP sizes open up faster than in spec GP's so in as short as a few thousand rounds, your GP has already started to erode (FYI).
One last comment about using a BM barrel for suppressed use. Besides the simple fact that this is a horrible idea, the MAJOR issue is that the threads on BM barrels tend to NOT BE concentric to the bore line. This means that the chances of you having a baffle strike is MUCH greater than if you were using say a Colt, BCM, DD, Noveske, etc. The majority of all baffle strikes I have witness or read about were on BM barrels.
C4
How would you know what is standard and what isn't?? How many mil-spec AR's have you owned?
Colt and LMT.
Since you live in WA, your knowledge about suppressors and how they affect AR's is going to be pretty limited.
WA only limited the use, not ownership. Been in the supressor game for three years now. Both rifle and pistol.
You can only notice differences IF you have a good frame of reference.
You're assuming I don't. Remember that whole "ass-u-me" thing.
There are SO MANY things that can change the ejection pattern that it really is a waste of time to use this as an identifier of ANYTHING.
Some of the things that will affect this is:
1. Ammo selection.
Which is why we have base standards. I.E. Mil spec M193 Nato ammunition which is the benchmark. Some also use M855, I do not.
2. Extractor tension (both the extractor insert and extractor spring).
Already covered this. Regular PMCS on the rifle and replacement with milspec parts as necessary.
3. Extractor wear.
Same
4. Buffer weight.
Same.
5. Buffer spring tension and length.
Same.
Just so you know, NOTHING about your BM is "within spec." BM doesn't follow a set standard. So back again to establishing a known standard.
It's not a Bushmaster gun. Only the barrel.
But that's neither really here nor there. There is an easy known standard. That standard is a mil-spec gun shooting mil-spec ammunition. Of which I've owned a few and shot that mil spec ammunition through them.
Ths gun behaves exactly the same. Hence, I have a benchmark performance set, and this gun matches it.
From day one, your "machine" AKA BM AR, has been assembled incorrectly. So if it it all the sudden became "in spec" the difference in it would make you think something is wrong.
Oh really? Did you actually bother to read what I wrote or are you simply assuming that my low post count means I am a noob with zero experience or that I didn't bother to follow the Mil-spec for assembling a rifle? I mean, it's not like that information is difficult to find out there in the great intarwebs.
Really? Are you sure? To start, the amount of carbon build up you have is much greater than if you owned a Colt. The amount of heat and pressure exerted onto the bolt are much higher. So your definitions of "normal" are not the correct version of normal.
Through several personally owned colts, and at least 15 other personally owned rifles of various flavors, not to mention the countless other rifles I have built or troubleshooted and repaired for others, I *think* I have a pretty good idea of what is "normal".
You BCG failed to lock back on the last round. That generally means that it is going to fast.
There are other possibilities as well. Dirty magazines, excessivly fouled gun, weak ammunition, or a combination of all of the above.
Given that the issues occoured near the end of the shooting session when the gun was at its dirtiest, rather then when it was freshly cleaned and lubed, I am very reluctant to say that was the issue. While I would most definitly consider excessive bolt speed as a culprit, there are too many other possible variables for me to choose that as the answer with any certianty.
Have any the AR's you have had experience with (for over a decade) been mil-spec? Suppressed?
Having ANY issues with a gun IS an issue, especially if you are going to bet your life on it. So I would be concerned and would be getting to the bottom of these problems REAL QUICK. This is why myself and some of the others have gone to great lengths to explain that your gun is WAY over gassed and then you added a suppressor for good measure (just in case you did not have enough gas in the system).
Grant, Let me start by saying that I do respect your knowledge, your work put into this website, and the fact that you're trying to "help".
At the same time, I would love to know how it's possible to diagnose a rifle from across the country without looking at the actual rifle. You've already shown that you understand that there are a LOT of different variables that can affect the behavior of a rifle, but you automatically jump to the assumption that because it's a bushmaster barrel and a supressor, that the issue is gross over gassing of the gun.
Not to be a dick, but that'd be like asking a doctor halfway across the country to diagnose a medical problem without having actually looked at the patient.
I have owned a rifle that was grossly overgassed. It was so bad that the ejecting brass was deflecting off of the brass deflector, bouncing forward and impacting the aluminum free-float handguard. It also exhibited the same behavior of excessive bolt speed and failed to lock back on the last round as you describe. THAT'S way over gassed. A Fulton ARmory adjustable gas tube fixed that issue.
I can get a lot of crappy AR's to "work." They are far from ideal though and would not use them for anything other than shooting dirt.
Call it what you will. I'd happily stand this "crappy" gun up against a milspec gun any day of the week. I have not ever had to tweak it to get it to work, i've never had to do anything except regular PMCS and it performs under any condition that i've placed it in.
If this makes it a "crappy" rifle in your eyes, so be it.
No GP erosion even needs to take place on your gun. You see, BM made sure that your gun had an out of spec GP size from DAY ONE!
Yet it still acts just like any milspec gun i've ever owned. Interesting.
It is also true that larger than spec GP sizes open up faster than in spec GP's so in as short as a few thousand rounds, your GP has already started to erode (FYI).
No argument there. That stands to reason.
One last comment about using a BM barrel for suppressed use. Besides the simple fact that this is a horrible idea, the MAJOR issue is that the threads on BM barrels tend to NOT BE concentric to the bore line. This means that the chances of you having a baffle strike is MUCH greater than if you were using say a Colt, BCM, DD, Noveske, etc. The majority of all baffle strikes I have witness or read about were on BM barrels.C4
Assumption time again. And completely irrelevant to the topic at hand. Not only that but I had the shoulder trued prior to bi-lock install and verified boreline to supressor after install.
As it were, the baffle strikes that were caused on this supressor by it's previous owner who works for a supressor manufacturer (1 stike), by me on an over heated LMT Mk18 pistol clone (two strikes). All strikes are minor although noticable, but do not affect performance to the naked ear. I have yet to test with equipment.
For what it's worth, I mean to be argumentative. There is much to be learned, and i'd hate to miss something possibly important because I just settled for an answer that is just one of many possibilities when there are other possibilites avalible.
Grumpy,
I not going to tit for tat respond to all of your points. However, I will say this. Those of us who have had experience with Bushmaster carbines can usually diagnose things about them even if we were on Venus.
The simple fact is that their strong point is the consistency in which they fail to do things. I have used a Hawkeye borescoper and scoped out a few BM barrels in my time. They were siginificantly larger than others I had seen.
It is a well known fact that BM gas ports are considerably larger than Colt, DD, LMT, Noveske and BCM.
So for example- when Grant states that it most likely is the gas port this assumption is based upon well know repeated variables and experience with their products and a particular set up.
Your "strawman" argument about running your set up against a "milspec" AR any day of the week is just that. An out of the box Colt 6920 will also run against yours without modification. So would a Daniel Defense and probably an LMT as well.
To be honest I am surprised that you are have fallen into the "I'm defending my choice of a crappy AR" camp.
Grumpy,
I not going to tit for tat respond to all of your points. However, I will say this. Those of us who have had experience with Bushmaster carbines can usually diagnose things about them even if we were on Venus.
The simple fact is that their strong point is the consistency in which they fail to do things. I have used a Hawkeye borescoper and scoped out a few BM barrels in my time. They were siginificantly larger than others I had seen.
It is a well known fact that BM gas ports are considerably larger than Colt, DD, LMT, Noveske and BCM.
So for example- when Grant states that it most likely is the gas port this assumption is based upon well know repeated variables and experience with their products and a particular set up.
Your "strawman" argument about running your set up against a "milspec" AR any day of the week is just that. An out of the box Colt 6920 will also run against yours without modification. So would a Daniel Defense and probably an LMT as well.
To be honest I am surprised that you are have fallen into the "I'm defending my choice of a crappy AR" camp.
Well stated.
To add, why anyone in their right mind would use a BM barrel (especially suppressed) is retarded. Especially given the fact that you SAY you have owned an LMT and Colt. If you did in fact own those two guns, why in the world would you not use them??????????????????
Just Sayin...
C4
Well stated.
To add, why anyone in their right mind would use a BM barrel (especially suppressed) is retarded.
So now i'm a retard for having a gun that works?
Like the old saying goes, even a blind squirrel finds an acorn every now and then. Would I expect this performance out of any BM barrel I came across? Absolutly not! I do believe that I just got lucky and i'm going to run with it until it stops working.
Especially given the fact that you SAY you have owned an LMT and Colt. If you did in fact own those two guns, why in the world would you not use them??????????????????
Divorce and child support are a bitch.
That and this rifle performed better then at least one of the Colt guns that I owned, so I decided to keep it instead.
Just Sayin...
C4
I understand where you're coming from. I really do. I am normally very much into the "Buy a Colt from the beginning and do it right" camp under normal circumstances. Were it not for the stellar performance of *this* rifle, we wouldn't be having this conversation at all.
That being said, is performance not the standard by which things are judged? This rifle performs. That's why I have it. If it didn't, I wouldn't. I have no desire for "project" guns that I have to **** with just to get them working properly. Last time I did that was with some speshul weapons/bobcat MP5 clones and I vowed never to do it again. Luckily I ended up breaking even on those when I got rid of them.
In the end, what we are really discussing are longevity issues. Since the rifle has always and is currently performing as well as any mil-spec gun, I'll keep using it. I understand that I probably have less then 5k rounds left on barrel life and i'm not worried about it. I planned on replacing it before then anyways. I've been looking at a Centurion barrel. How do you feel about those?
But this rifle is still working right now, and doing very well at it. It shoots around 3moa which while nothing to write home about, is acceptable "combat" accuracy. It goes bang every time I pull the trigger and the only issues i've ever had with it are at times when i'm well past the "use" stage and into the "abuse" stage. Yet even then it continues to actually work and once I clean it, the small issues go away and it works fine just like it's supposed to.
If we really want to get into comparisons, please feel free to do the same thing with a milspec gun and report how it performed. I'd frankly love to see the results. Not because I think it will choke up, but simply because I like having a performance benchmark. Especially since I've never done anything like what what I did this weekend with a milspec gun.
Grumpy,
The simple fact is that their strong point is the consistency in which they fail to do things. I have used a Hawkeye borescoper and scoped out a few BM barrels in my time. They were siginificantly larger than others I had seen.
And i'm absolutly not arguing this or disagreeing with it. I understand what you are saying and understand that my gun probably has the same issue.
What I am saying is that in this particular gun, this issue has not affected performance....yet. I'm expecting it in the future, but it has yet to manifest itself.
It is a well known fact that BM gas ports are considerably larger than Colt, DD, LMT, Noveske and BCM.
So for example- when Grant states that it most likely is the gas port this assumption is based upon well know repeated variables and experience with their products and a particular set up.
This is where we diverge. Understanding that BMs have oversized ports to begin with and that this rifle has 8 to 10K rounds down the pipe, I can easily see the logic behind what you're saying.
But that doesn't explain why it doesn't have this issue when it's freshly cleaned and the bolt speed is even greater (still using the suppressor). Because of this, the "most likely" explination is cast into doubt.
It's that one factor that's sticking in my craw and making me say "I can't bring myself to definitivly say this is the issue".
To be honest, right now i'm leaning more towards the ammunition (BVAC) as the culprit simply because of the dirty performance compared to clean performance.
Your "strawman" argument about running your set up against a "milspec" AR any day of the week is just that. An out of the box Colt 6920 will also run against yours without modification. So would a Daniel Defense and probably an LMT as well.
I don't see how saying that this gun running as well as a Milspec gun counts as a straw man argument. It's merely a statement of fact. I've run my own Colts, my own LMT, and i've run next to plenty of those guns owned by others. This gun has kept up with them all and has actually done better the a few.
Havn't "had" to modify this gun either. It ran fine before the FZ BCG too. Matter of fact, I had the original BCG in my gear this weekend in case the FZ ****ed up. I want my gun to run like it did before and was ready to replace it with my original parts if the FZ BCG did fail.
To be honest I am surprised that you are have fallen into the "I'm defending my choice of a crappy AR" camp.
No, i'm not defending crappy guns as a whole especially bushmaster, i'm defending *this* crappy gun because it continues to perform, even when I do stupid shit like not clean it for 1100 rounds and shoot over half those rounds with a suppressor attached.
TonyTacoma
07-28-11, 23:20
Grumpy,
I not going to tit for tat respond to all of your points. However, I will say this. Those of us who have had experience with Bushmaster carbines can usually diagnose things about them even if we were on Venus.
The simple fact is that their strong point is the consistency in which they fail to do things. I have used a Hawkeye borescoper and scoped out a few BM barrels in my time. They were siginificantly larger than others I had seen.
It is a well known fact that BM gas ports are considerably larger than Colt, DD, LMT, Noveske and BCM.
So for example- when Grant states that it most likely is the gas port this assumption is based upon well know repeated variables and experience with their products and a particular set up.
Your "strawman" argument about running your set up against a "milspec" AR any day of the week is just that. An out of the box Colt 6920 will also run against yours without modification. So would a Daniel Defense and probably an LMT as well.
To be honest I am surprised that you are have fallen into the "I'm defending my choice of a crappy AR" camp.
I agree, and to be honest this is a defense of my crappy rifle thread, so much so the original topic is no longer in play. Only thing left is people stating why his rifle is having problems and him defending every explanation that gets stated. This same thing happend in another thread that turned into grumpy defending crappy rifles again. IMHO I think we've all heard enough of why this particular rifle is having problems but there's no way it could be the shitty barrel.
This thread can be closed at any point.
I agree, and to be honest this is a defense of my crappy rifle thread, so much so the original topic is no longer in play. Only thing left is people stating why his rifle is having problems and him defending every explanation that gets stated. This same thing happend in another thread that turned into grumpy defending crappy rifles again. IMHO I think we've all heard enough of why this particular rifle is having problems but there's no way it could be the shitty barrel.
This thread can be closed at any point.
Wow....havn't even bothered to read the thread I see.
Which problems is this rifle experiencing again that a "milspec" rifle wouldn't experience under the same conditions?
And which crappy rifles did I defend before? I remember saying that I think it's a good thing that another company (Stag) is making a full, milspec rifle, but I don't remember defending a crappy rifle.
Please feel free to prove me wrong.
On that note, do you have anything worthwhile to add to this thread besides trying to start a dogpile?
ETA: as to this thread going anywhere and being locked, i'm still open to theories for the rifles behavior that would explain the reason why it would have excessive bolt speed while filthy, yet not when clean and lubed. Especially if the gas port is the reason. Still something to be learned here. No need to lock it.
Magic_Salad0892
07-29-11, 03:33
Theory time!
On a cleaned and lubricated upper receiver the interior of the phosphate upper is kinda ragged, and not smooth if you look at it with high powered magnification.
Let's say it's possible for the FZ Carrier to drag on that surface...
However...
combining lubricant, with carbon creating a smoother, and slicker ''mud'' combined with the inherent lubricity of the Nickel Boron, and you're not dragging the carrier on the same ''ragged'' surface, your dragging it through an aluminium tube with a mud lubricant on it, that gives way to the hot ass piece of metal being pushed through said ''tube''.
tl;dr:
Upper receiver's micro jaggedness possibly caused by phosphate doesn't give way because it's a metal coating. Lube + Carbon =/= mud, which does give way, and lubricates the gun further.
Probably isn't true but it's a theory.
Also I'd like to note something:
You're gas port may be nearing .085-.090'' because of gas port erosion, if you've fired 8k rounds through it. If you're running a super large gas port already, then it's allowing even more hot gas through it which will further speed up the port erosion, and give you more gas... smaller ports take longer to erode because there is less room for hot gas to push into to begin with.
Hope what I said made sense...
Theory time!
*snip
Hope what I said made sense...
You made sense. Not sure if that's the reason, but anything is possible.
Looks like i'm gonna punch the FSB and check the port sometime soon.
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