View Full Version : Questions Regarding AR Reliability
ladders1901
04-15-08, 09:52
What exactly happens to an AR DI system when exposed to sand (and mud and dirt) that causes them to jam? Does the problem arise when the sand gets between the bolt carrier and rails, between the bolt and the bolt carrier, locking lugs and barrel extension, etc. What's happens with the AR DI system that doesn't happen to the piston/AK systems that apparently make them more reliable?
I'm not new to ARs and I do understand the cleaning and maintenance required. I also understand that the DI system is dirty, but I am curious to hear from people with experience regarding the above.
As always, thank you.
Don't believe rumors, go test it for yourself.
Failure2Stop
04-15-08, 12:52
Issues with dirt and sand have more to do with tight tolerances than operating system. However, it seems that direct mechanical pressure during initial carrier movement helps overcome debris in the system.
Traditional piston operation is more of a benefit when firing sustained full-auto, from a Short Barrel, or with suppressor use, and especially when all three are present. It has much more to do with reliable function even with extremely heavy fouling.
Stuffing a piston into an AR does not make it an AK.
all AR reliability problems are mag related.
well not all, but 90% i'd say.
P-mags. if only they were legal in my state. :rolleyes:
here's a Q for those who've operated AR's in sandy/muddy/horrible conditions...
does grit and stuff beat the shiznit out of the upper's anodizing?
what's it take to wear an upper out due to grit? basically just has to guide the bolt/carrier assembly into the barrel extension right? so you can have it pretty sloppy i'd think...
ladders1901
04-15-08, 17:58
Thanks for the information.
I don't have any experience with the HK system, but many claim (based upon experience) that it's more reliable in dirty/sandy/dusty environments. Given that the bolt carrier and bolt are similiar to the AR (I don't know about the tolerances) I was curious where this reliability came from. A portion of the reliability gain must come from the fact that the piston system runs cooler.
I agree a piston in an AR does not make it an AK. One of the big advantages the AK has over the AR in terms of reliability are looser tolerances.
Thanks.
1/3 of the failures of the M4 during the dust trials were magazine related.
all AR reliability problems are mag related.
well not all, but 90% i'd say.
P-mags. if only they were legal in my state. :rolleyes:
P-mags not legal? What communist state is that and why?
P-mags not legal? What communist state is that and why?
There are several communist states that don't allow 30 round magazines, which is all you can get the PMAG in currently. 20 rounders should be out any day now.
The Bay State is one of the states where newly manufactured high capacity magazines are not allowed. We can have all the prebans we can buy, but nothing newly manufactured. Makes sense doesn't it? P-Mag buyers with a need to void themselves of USGI contract 20's and 30's without date codes, (pre-ban) need only drop me a PM...
P-Mag buyers with a need to void themselves of USGI contract 20's and 30's without date codes, (pre-ban) need only drop me a PM...
I'll check my inventory. I might have some.
I'll check my inventory. I might have some.
Awesome. I have been meaning to post a WTB in the Classifieds. I have some now, will likely be looking for more down the road and know folks here in the PRM who are looking right now. I can all but guarantee they will be gobbled up by folks hungry for sanely priced prebans.
Back on point, where is the mechanism by which failures occur by "dust+magazine". I'm not doubting it at all, just curious. Is it a poorly fitting magazine which allows dust/dirt/muck to accumulate around the carrier, or is it something else?
I read a review of a Stag a year or two ago in Shotgun News. One picture showed a mag with mud falling out of it. Another showed a stack of Wolf ammo. The thrust of the article was on Stag's reliability regardless of condition, and the caption for pic #2 said something like, "It'd take more Wolf than this to stop a Stag." This article was important to my decision to move forward with the AR platform and buy my first. Very happy with the decision; I don't really consider spending money on an AK anymore.
There are several communist states that don't allow 30 round magazines, which is all you can get the PMAG in currently. 20 rounders should be out any day now.
Guess I am spoiled in conservative, gun friendly Utah.
the caption for pic #2 said something like, "It'd take more Wolf than this to stop a Stag."
I love that!:D
I tell my brother-in-law that constantly...but he still uses Wolf.
I read a review of a Stag a year or two ago in Shotgun News. One picture showed a mag with mud falling out of it. Another showed a stack of Wolf ammo. The thrust of the article was on Stag's reliability regardless of condition, and the caption for pic #2 said something like, "It'd take more Wolf than this to stop a Stag." This article was important to my decision to move forward with the AR platform and buy my first. Very happy with the decision; I don't really consider spending money on an AK anymore.
While the ads are nice in Shotgun News all of the articles are written as ads as well.
Agreed. I'm not running out to buy a Doublestar Patrol LW...but those SN articles were a starting point for this noob, until I ran into this site, full of esteemed professional info :cool:
BTW I recently re-read the one about the 6.8spc, which I found generally informative.
P-mags not legal? What communist state is that and why?
post ban.
ny.
:mad:
here's a Q for those who've operated AR's in sandy/muddy/horrible conditions...
does grit and stuff beat the shiznit out of the upper's anodizing?
what's it take to wear an upper out due to grit? basically just has to guide the bolt/carrier assembly into the barrel extension right? so you can have it pretty sloppy i'd think...
My experience is no. The anodizing is pretty tough.
My experience is no. The anodizing is pretty tough.
cool.
i can see some slight wear marks in mine, but not even through the ano. :cool: (1300 rounds)
Failure2Stop
04-16-08, 23:01
all AR reliability problems are mag related.
well not all, but 90% i'd say.
This is a bit optimistic.
Bolt failure has nothing to do with magazines. Gas port erosion has nothing to do with magazines. Excessive bolt velocity has nothing to do with magazines. Failure-To-Extract stoppages have nothing to do with magazines. Failure-to-Eject stoppages have nothing to do with magazines. Torn case heads/rims have nothing to do with magazines.
While some stoppages are related to magazines, and replacing the magazine or upgrading the follower and/or spring will eliminate the issues (providing that the tube and feed-lips are still sound), there are issues that are solved with a mechanical approcah to the OP system.
does grit and stuff beat the shiznit out of the upper's anodizing?
Not really. Improper cleaning hurts anodizing more than operational exposure. Normal wear and tear will wear the edges, and bolt cycle will wear the race-ways inside the upper.
This is a bit optimistic.
Bolt failure has nothing to do with magazines. Gas port erosion has nothing to do with magazines. Excessive bolt velocity has nothing to do with magazines. Failure-To-Extract stoppages have nothing to do with magazines. Failure-to-Eject stoppages have nothing to do with magazines. Torn case heads/rims have nothing to do with magazines.
While some stoppages are related to magazines, and replacing the magazine or upgrading the follower and/or spring will eliminate the issues (providing that the tube and feed-lips are still sound), there are issues that are solved with a mechanical approcah to the OP system.
Not really. Improper cleaning hurts anodizing more than operational exposure. Normal wear and tear will wear the edges, and bolt cycle will wear the race-ways inside the upper.
+1 to all of the above, as I stated before, only about 1/3 of the failures during the M4 dust tests were attributed to the mags.
Thanks F2S....I learn something new every single day it seems and this one is no exception.
Parabellum9x19mm
04-17-08, 16:06
as i understand it, the major problems with the AR are (as previously stated) magazine and extractor related. I don't really see how a OP system solves either issue.
gas port erosion to the point of causing problems is pretty rare. I understand that the gas port is a different size on piston systems and the system istelf might be more forgiving when it comes to operating pressure variation....but if the gas port is still in the CAR location, does it really solve anything in regards to a problem that most peope will never see outside of a message board?
as far a bolt faliures, the piston deffinatley has an edge, because the bolt isn't cooked at high temps like in the DI. then again, a spare bolt is like $50...not a big issue, unless it fails when you're under fire.
Failure2Stop
04-18-08, 00:43
as i understand it, the major problems with the AR are (as previously stated) magazine and extractor related.
Yes and no. Other than magazines, one of the easiest to solve issues is with extractor tension. It has been addressed and solved. Black buffer, proper 5 coil spring, and use of a Crane O-Ring for carbine length gas systems. Check extractor for proper sharpness. Issue solved.
I don't really see how a OP system solves either issue.
OP system change solves other issues, especially with bolt temperature, lubricant stripping, fouling in the OP system, fouling sensitivity, bolt velocity, and sensitivity to external debris.
gas port erosion to the point of causing problems is pretty rare. I understand that the gas port is a different size on piston systems and the system istelf might be more forgiving when it comes to operating pressure variation....but if the gas port is still in the CAR location, does it really solve anything in regards to a problem that most peope will never see outside of a message board?
It seems to me (about as un-scientific a statement as possible) that gas port erosion is an issue with two variables: gas port location and barrel composition. Since we are pretty stuck on the TDP, we haven't advanced barrel technology in serious guns since 1964 or so.
I also agree with your implication that most people will not see the advantave of an OP system change.
However, those that shoot full auto (and suffer the temperature/wear issues it creates) will appreciate the cooler bolt. Those that shoot suppressed will appreciate how much more lube stays on the bolt, how much less fouling is present in the OP system and magazine, and eliminate the need for gas-buster charging handles and such. Users of SBRs will appreciate how much less sensative the system is to barrel length for uniform reliable function. Those that use two of these possibilities will definately appreciate a non-DI OP system. Those that use all three won't want to go back ever.
as far a bolt faliures, the piston deffinatley has an edge, because the bolt isn't cooked at high temps like in the DI. then again, a spare bolt is like $50...not a big issue, unless it fails when you're under fire.
The crux of the matter. It's all rhetoric until your life dangles from it. Frankly, most people's won't. But some do, and those are the ones that get issued the guns, or should be.
Nothing wrong with buying your own though. I am not going to until prices drop into the reasonable category (or I find a box of money) or an alternative is successfully fielded.
AllAmerican
04-18-08, 08:55
here's a Q for those who've operated AR's in sandy/muddy/horrible conditions...
does grit and stuff beat the shiznit out of the upper's anodizing?
what's it take to wear an upper out due to grit? basically just has to guide the bolt/carrier assembly into the barrel extension right? so you can have it pretty sloppy i'd think...
Combat
variablebinary
04-18-08, 10:44
What exactly happens to an AR DI system when exposed to sand (and mud and dirt) that causes them to jam? Does the problem arise when the sand gets between the bolt carrier and rails, between the bolt and the bolt carrier, locking lugs and barrel extension, etc. What's happens with the AR DI system that doesn't happen to the piston/AK systems that apparently make them more reliable?
I'm not new to ARs and I do understand the cleaning and maintenance required. I also understand that the DI system is dirty, but I am curious to hear from people with experience regarding the above.
As always, thank you.
It can be a combination of things I suppose. Fouling + foreign matter in the action + cooked off lube due to heat + tighter than AK tolerences
However the biggest issue isnt the DI action, its mags.
Tried googling crane o ring that was talked about above where does it go and what does it fix?
ladders1901
04-18-08, 11:34
Many thanks for all of your responses to my questions. I made the post while overseas on business so I had very little time to read the answers until I returned yesterday and caught up on them today.
The answers were all very helpful. It sounds like tolerances and heat are the remaining culprits. The other issues (like extraction) have been solved.
The crane o ring is placed between the extractor and the bolt. The extractor spring and plastic bumper fit inside the o ring. The o ring increases the extractor tension and improves the extraction reliability.
Thanks.
I know it is a slightly different animal from the M4, which seems to be the subject matter when dust tests come up, but when I when I was in the Army I had an M16A2 (didn't get an M4 until just before I got out). The only time I ever had problems with it was one day during qualifying when I was given two beat up ugly mags with 20 rds. each. I could just tell I was going to have problems and did. It would fail to feed every other round. It was a pain to qualify doing SPORTS as my targets were popping up and falling back down unchallenged but I still managed to , barely. My CO who was watching just laughed and got me two different magazines and allowed me to requalify (where I was able to shoot 40/40 without stoppages). Fast forward about a year I found myself in the desert with a wall of sand hundreds of yards high coming at us and when we were in it I couldn't see 5 ft in front of me. The rifle later that day was able to fire through four and a half mags with no stoppages although I made sure my dust cover was closed while in the sandstorm. Not exactly a scientific test but I was happy with my rifles performance. While I agree 90% may be optimistic for mag related stoppages as a whole; my experience would concur with skyugo's comment. The only other time I've had an AR jam was with my civy home-build that had a FTE when my thumb blocked the dust cover from opening when using a magwell hold.
Roughly 90% of the troops issued an AR/M16 platform report that they are confident in the weapon and its ability to do the job. During testing when the original M16 was adopted, it was proven to be SIGNIFICANTLY more likely to go "bang" than the Garand and M14.
It is a reliable weapon and imho a piston system is an answer in search of a problem unless you do a lot of shooting supressed. You have to clean that crap out of the piston, ect. just like you do a DI rifle's reciever. Saying "it shits where it eats", while humerous, would be more accurately phrased as "DI uppers shit in the kitchen instead of the living room like a piston upper." Either way you are going to have to clean your weapon at some point and that point will be LONG AFTER you have fired your combat loadout.
Getting a paint-brush and some mineral-spirits it takes me all of 5 minutes to clean my upper (not counting the bore/chamber, which is a simple matter, just takes time for the solvent to do it's job).
No dental tools
No need to get in the crevices with a pick
Just paint it down/flush/brush it out liberally with a 1" paint-brush and mineral spirits and let it evaporate and CLP it.
The BCG? Soak it in mineral spirits, let it dry, take a .223 bore-brush to the tail of the bolt, cleans ALL the carbon off. Then take a worn brush to the inside of the gas-key, twist it in a few times. Then take a wooden dowel pin or your firing-pin with a patch wrapped around hte base of it or use a stripper clip and clean out inside the carrier.
Getting and AR "functionally" clean takes all of 10 minutes, if that.
White-glove cleanlyness, while nice, is not needed for the rifle to function. Complaining that the rifle is a poor design because getting it white-gloves clean is "hard" or "time consuming" is like complaining that the paint on M855 is not evenly distributed on the tip and may induce slight amounts of instability and wobble. It simply doesn't matter from any practical standpoint.
The one thing that NOONE has mentioned here is the solution to bolt-failure, especially in carbine length gas systems. There are bolts made out of much stronger/more advanced steel than the 60's era Mil-spec for current bolts. If you are worried, spend the $65 or so and get one.
post ban.
ny.
:mad:
I was able to pick up about a dozen pre-ban Colt 30-rd for 17 bucks a piece from my PA dealer. I'm in NY, but the PA border is 2 blocks away (yes, it HURTS).
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