AR being uncooperative

[Perplexed]

At the range now. This time, I loaded one round to see if the bolt would lock back on a known good, empty USGI metal magazine. After reseating the gas block and using a clipped carbine spring and a 3 oz. carbine buffer, with these brands of ammo:

The bolt would not lock back with either of the first two brands, but would lock back with the American Eagle 5.56 ammo. Tried ten rounds of the AE to see if I would have any cycling problems, and had none. Then I switched to a PMAG 30 rounder, and the bolt would not lock back after a single round of AE. However, the bolt did cycle ten rounds of the AE through the PMAG, and locked open after the last round.

So it looks like that right now, the AR is indeed ammo sensitive and even with the AE 5.56, cycling is marginal. Drilling out the gas port is looking more and more like the solution.

 

[lasher]

super easy to enlarge the gas port in the barrel. i did 3 last week in a very short time, my reloads were using a very fast powder and wouldn't cycle. all functioning well now. just remember to run a dowel or perhaps a cleaning rod into the bore so you don't damage the opposite wall of the bore. little force is needed, the bit will pull it's way thru and a final increase in downward force to penetrate the inner bore wall

 

[rc508pir]

At the range now. This time, I loaded one round to see if the bolt would lock back on a known good, empty USGI metal magazine. After reseating the gas block and using a clipped carbine spring and a 3 oz. carbine buffer, with these brands of ammo:

View attachment 103284

The bolt would not lock back with either of the first two brands, but would lock back with the American Eagle 5.56 ammo. Tried ten rounds of the AE to see if I would have any cycling problems, and had none. Then I switched to a PMAG 30 rounder, and the bolt would not lock back after a single round of AE. However, the bolt did cycle ten rounds of the AE through the PMAG, and locked open after the last round.

So it looks like that right now, the AR is indeed ammo sensitive and even with the AE 5.56, cycling is marginal. Drilling out the gas port is looking more and more like the solution.

didn't you say that it would fire the wolf gold before? Also, is the AE 55gr or 62gr?

 

[Perplexed]

didn't you say that it would fire the wolf gold before? Also, is the AE 55gr or 62gr?

It would cycle Wolf Gold about one out of four or five times. The AE is 55 grain.

Btw, my earlier comment about Wolf Gold running fine was in another AR with a 14.5" barrel.

 

[rc508pir]

That's odd it wont cycle the Wolf but the AE runs fine. The Wolf is only Wolf branded. Its basically Taiwanese m193 and should run if the AE does.

In anycase, the end state should be that it cycles any 223 or 556 that you put through it. You said the port size now is .091 now right? Id have it opened to .1 after you put a unclipped buffer spring back in. That's what id do anyway

 

[Perplexed]

It's actually 0.093 at present. I just bought a set of drill bits - amazing how some hardware stores only have fractional sizes (think 1/32, etc.)in drill bits. The bits closest to the recommended gas port sizes go from 0.23mm right to 0.27mm - nothing in between. I did find titanium nitride-coated bits at Harbor Freight in the numbered sizes 10-60 or some such, so I'll try opening up the port with my drill press.

 

[rc508pir]

Oil it liberally and gooooooo verrrrrrry slow. If you have a smart fone, download a conversion app like Convert

 

[Perplexed]

Nah, I just used this chart:

http://bobmay.astronomy.net/misc/drillchart.htm

 

[Perplexed]

Well, this weekend I bored out the gas port to 0.098, and tried the AR at the range today with a standard spring and 3 oz carbine buffer. This time around, it cycled all the AE 5.56 and locked back on empty; it cycled the Wolf .223 about every 4 out of 5 times, and locked back on empty; and it would cycle the Champion about 2 out of 5 times, but not lock back on empty. So some progress, but this is getting rather ridiculous!

On the bright side, this AR continues to have, by far, the mildest recoil I've yet experienced in a 5.56 AR.

 

[rc508pir]

Progress is progress. Just go in small increments till it will cycle that Champion. Had a feelin it was that gas port