8 most common AR failures

[budlight]

On my last hunt I had some feed failures. Kind of dissappointing when you steady for a shot and the trigger doesn't break. The 20 inch 11 degree target crowned non threaded barrel, rifle length gas tube and Non Adjustable gas block. I kind of built for 62 and 69 grain only with a H1 buffer weight(I think 3.8 oz) , m-16 bolt, and heavier carbine length spring. The problem started when I was only shooting 55 gr. HPBT 28 gr of cfe 223. 5.56 loading and right at 3300 fps on the chrono. I am going to try a lighter buffer spring because it passes the gas ring test, perfectly clean and 3 different 10 shot new P-Mags.

Has anyone ever cut a few coils off of a carbine spring to make their action do a full cycle or for some undergassed problem. Any other fixes like a change to buffer weights?

8 Most Common AR-15 Failures & How To Fix Them

The AR-15 is reliable but can still have some hiccups. We go over a couple of the most common AR-15 failures and how to fix them.

www.pewpewtactical.com

 

[TargetShooter2]

I went through a problem like yours also on a 20 inch Bull barrel
that i put together for a pd trip, it had a rifle buffer tube with a moe rifle stock
and it ran good , was pushing my 55 load @ 3150 fps , then i went and changed it
up before my trip with a PRS lite and carbine buffer tube then i started to get FTE/ FTF/ over ride ended up going with a 2.9
buffer and i greased the inside of the tube/buffer & spring lightly this rifle will run
anything i put through it now , .
A standard carbine buffer spring is 10.5” in length and has 37–39 coils. and mine was
10.5 that i used .

• Carbine: 3.0 oz, used in shorter barrel rifles
• H1: 3.8 oz, used in mid-length barrel rifles
• H2: 4.6 to 4.7 oz, used in longer barrel rifles
• H3: 5.1 to 5.4 oz, used in rifles with more powerful ammo
• H4: 6.8 oz, used in rifles with shorter gas systems

from another source :

A standard carbine buffer should weigh 2.9 ounces.
Moving up in weight, an H buffer, or Heavy Buffer, is nearly a full ounce heavier at 3.8 ounces.
The H2 buffer has a slight variance depending on the manufacturer but should be 4.6 to 4.7 ounces.
An H3 buffer similarly should be between 5.4 and 5.5 ounces depending on the manufacturer.

 

[ARlife4me]

what it doesn't talk about is the 9th failure.............gas port size and I've had some that weren't fixable with an agb. in my 50 or so that I've built there have been 6 with that issue (1 308win and 3 6.5creed and 2 260rem). adding more buffer weight can help in some instances but increases felt recoil. I state this thru my experiences.

 

[HRM Johnny]

Tag

 

[tim1457]

Tag

 

[SDPlinker]

Inspect your BCG first for gas bypassing, then go from there. Inspect block alignment also!

 

[budlight]

So Maj. I have a new carbine spring/buffer weight that i will try. 2.9 and seems to be less tension spring.

 

[budlight]

Inspect your BCG first for gas bypassing, then go from there. Inspect block alignment also!

It's a low round rifle and I machine dimples in the barrels for the gas block set screws. I also coat the barrel with Permitex high temp red silicone so I never have gas block to barrel leakage. Lessons learned from one of my first stainless builds. Just for the heck of it I pulled out the NB BCG did install one of my spare chrome full auto bolts and it was doing the same thing

 

[SDPlinker]

Sounds like you have the bases covered then, looking forward to the remedy. I buggered mine up, installed adjustable gas block, took out Sunday and click, no boom. Thought the gas tube was a bit proud but didn't give a second thought until Sunday. Took it back apart and sure enough, missed the hole with the pin OOPS!!!

 

[highbrow]

Sometimes the gas port is too small and needs to be opened up. Rifle length 556 should be around .096. Larger if you are running an agb.

 

[ARlife4me]

.750 Dimpling Jig

slrrifleworks.com

I invested in 1 of these for all 4 sized journals (.625, .750, 875 & .936). Never had any questions about alignments after that! I prefer the bottom screw type than clamp or pins for the ease of it. Now I just need to get someone to ream the gas ports so the problem children (barrels) will get back in line again. The 1st 2 6.5G I had were tight chambers and loosened up after 50-100 rounds. when going together with NEW parts there shouldn't ever be any question if they work, but some slip thru the cracks with qc. Diagnosing online can be difficult especially if the person doesn't have the tools necessary to answer/address the issue(s).

 

[ARlife4me]

.750 Dimpling Jig

slrrifleworks.com

I invested in 1 of these for all 4 sized journals (.625, .750, 875 & .936). Never had any questions about alignments after that! I prefer the bottom screw type than clamp or pins for the ease of it. Now I just need to get someone to ream the gas ports so the problem children (barrels) will get back in line again. The 1st 2 6.5G I had were tight chambers and loosened up after 50-100 rounds. when going together with NEW parts there shouldn't ever be any question if they work, but some slip thru the cracks with qc. Diagnosing online can be difficult especially if the person doesn't have the tools necessary to answer/address the issue(s).

11 of 17 are for AR's, 3 for Glock and M&P's and 3 for BA and Lever's. Either they contain small parts or small tools for the jobs.

 

[Josh06]

On my last hunt I had some feed failures. Kind of dissappointing when you steady for a shot and the trigger doesn't break. The 20 inch 11 degree target crowned non threaded barrel, rifle length gas tube and Non Adjustable gas block. I kind of built for 62 and 69 grain only with a H1 buffer weight(I think 3.8 oz) , m-16 bolt, and heavier carbine length spring. The problem started when I was only shooting 55 gr. HPBT 28 gr of cfe 223. 5.56 loading and right at 3300 fps on the chrono. I am going to try a lighter buffer spring because it passes the gas ring test, perfectly clean and 3 different 10 shot new P-Mags.

Has anyone ever cut a few coils off of a carbine spring to make their action do a full cycle or for some undergassed problem. Any other fixes like a change to buffer weights?

8 Most Common AR-15 Failures & How To Fix Them

The AR-15 is reliable but can still have some hiccups. We go over a couple of the most common AR-15 failures and how to fix them.

www.pewpewtactical.com

I tried cutting coils on a few in the past and ended up opening the gas port a little to get them running reliably.

 

[ARlife4me]

I tried cutting coils on a few in the past and ended up opening the gas port a little to get them running reliably.

proper port size is a better option than going heavier on the buffer. that's if you can and if not then just adding mass might be the only choice?