Questions Regarding AR Reliability

AR/M4 AR General Discussion
21

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.

22

+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.

23

Thanks F2S…I learn something new every single day it seems and this one is no exception.

24

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.

25

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.

26

Combat

27

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.

28

Tried googling crane o ring that was talked about above where does it go and what does it fix?

29

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.

30

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.

31

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.

32

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).