AR not chambering next round

[calebp]

That's part of the method that I recommend for all new guns, new builds, or for diagnosing problems.

Get a minimum of 12 magazines. Mark each mag so you can tell them apart (a Sharpie and numbers are perfect).

Lock the bolt to the rear, insert the first mag, hit the bolt release, and fire. Look for:
-vigorous ejection
-bolt locks to the rear

If it does both, go to the next mag. If it goes through all 12 mags without a hitch, you're good to go.

If it fails to lock back on one of the mags, sit that mag aside. If the other 11 mags work lock the bolt to the rear, then take the suspect mag and run it about 8 more times, 1 round at a time. If it doesn't fail again, it could have been a fluke. If it fails to lock back at least 1 more time, you have a bad mag. Replace it, repair it, or use it for a dedicated training mag.

If more than one magazine fails to lock the bolt to the rear, you have an issue with the firearm. Undergassed usually, but it could be too much buffer/spring, bad bolt catch/spring/plunger, issues with the BCG, etc.

Is the fix for an undersized gas port to just drill it out? Guessing that’s something you can fix if so?

FWIW: when I was focusing on holding it extremely firmly it ran through full mags of Tula with mostly no issues. It was when it was being held slightly loosey goosey that issues presented.

 

[medium187mph]

Curious on what ammo you were running? 223 or some 556?

 

[cmshoot]

Is the fix for an undersized gas port to just drill it out? Guessing that’s something you can fix if so?

Yessir, reaming it out to the proper size. I have all the reamers for that.

 

[calebp]

Curious on what ammo you were running? 223 or some 556?

Like a dumbass I ran the mags I brought of m855 sighting in the other rifle I took. Only had Tula and some local reloads to sight in and function test the shorty.

 

[greg vess]

I would start with opening the gas block up all the way. That will rule out gas restriction and make sure it's not short stroking. That's a no money test then I would go back to the buffer and weigh it to see what you have.

I have had that happen with cheap gas blocks. I prefer a gas block that you have to coax or heat a little to get it on. With the rifles I have messed with 8 times out of ten it's a bad part in the gas system. I would however check those no cost test first. The rifle might have been set up for a particular ammo and you might have picked a ammo that is not as hot causing the problem. Check all that out before dumping money into it.

 

[medium187mph]

Like a dumbass I ran the mags I brought of m855 sighting in the other rifle I took. Only had Tula and some local reloads to sight in and function test the shorty.

So you experienced cycle issues using Tula and reloads? I reload my own and have had cycling issues when I’ve dropped light powder vs mid/heavy charges.

I’d head back to the range with some of that m855 before doing anything drastic to the set up.

 

[cmshoot]

So you experienced cycle issues using Tula and reloads? I reload my own and have had cycling issues when I’ve dropped light powder vs mid/heavy charges.

I’d head back to the range with some of that m855 before doing anything drastic to the set up.

This.

Tula is notoriously under-powered, and I’ve no idea what your reloads are like.

With that said, I build my personal AR’s so they’ll cycle everything from crappy Tula and PMC Bronze, up through M193/M855 +, and everything in between.

As non-military, if you can’t use whatever ammo you happen to be able to source in your AR, I would say it is of limited use.

Your AR SHOULD run with Tula. This leads me to lean toward the under-sized gas port hypothesis.

 

[greg vess]

This.

Tula is notoriously under-powered, and I’ve no idea what your reloads are like.

With that said, I build my personal AR’s so they’ll cycle everything from crappy Tula and PMC Bronze, up through M193/M855 +, and everything in between.

As non-military, if you can’t use whatever ammo you happen to be able to source in your AR, I would say it is of limited use.

Your AR SHOULD run with Tula. This leads me to lean toward the under-sized gas port hypothesis.

That was going to be my next suggestion. Get some real ammo!

 

[Tony2X]

AR not chambering next round​

Buy an AK....LOL

 

[cmshoot]

A well-balanced AR will everything from Tula/PMC Bronze to M855, suppressed and non-suppressed, without resorting to a an adjustable anything.