Diagnose this AR

[luckyned7]

It is a factory gun with aftermarket built upon with a few hard miles but still very accurate. I’m not the orginal owner so I can’t give all of it’s history. In my beginning history, it would fail extraction, leaving the brass stuck in chamber. I felt it over gases so I installed new buffer spring, H buffer and a new extractor-spring w/o ring. Several hundred rounds later and a year of time...
She fired 2 but I could not exstract the 3rd round to clear rifle. I mortared, cleaned and inspected and load 3 factory rounds and it refuses to go into battery. I went back home to diagnose and found I can jam the bolt on factory ammo. Hmm? I don’t care about this rifle BUT I would like to learn why so I’m smarter.
Your thoughts are welcome.

[GTRUCKER]

Is there a broken casing in the chamber?

[Lycanthrope]

Is there a broken casing in the chamber?

Well.....we hope not.

The whole H buffer and milspec round and perfect chamber is a great place to start. It's not prefect. You can get better accuracy from other options.

Lycancanelaboratethrope

[Gunsnwater]

Not enough information. 223 or 5.56? How clean is it? How do rounds fit when pushed in by finger? Do they fall out? Bolt operation empty? Cracked or peened lugs on extension or bolt? Cam and cam pin condition? Gas rings? Chrome chamber?

Sounds like you were ripping off the extractor from the case rim so you added mass and a better but not tightest grip possible (no o ring) on case. It worked for 2 years but now it holds on to case without tearing off the rim, but slamming but on ground pulls the case out?

If that’s all true it’s not the case gripping the chamber walls. The rim is not ripping off. That’s what a stuck case does. A rusted pitted chamber can do. Now look into the camming of the bolt and any interference of that action. Piece by piece, bolt in carrier, bolt in extension. Stripping the bolt and headspace gauges would be in there if you want to be thorough. Finally a bore scope to look around.

Oh almost forgot, what’s barrel length and gas system length? Gas block pinned or set screw?

[Gunsnwater]

Forgot this check. Empty chamber, how does the action work? Now try it with a cleaning rod pushing on the bolt face hard. Compare that with a working AR.

[luckyned7]

Thank for fast posts. Gonna add what I can and my guess without knowlege before bed.. Rifle started life as a Dpms carbine but at some point got a gas block and quad rail. Barrel is 16” dpms and so is most everything else. Accurate barrel but bolt can jam tight on unfired round. Was working on 193ball and handloads run through small base reloading die. (past)- (present)-Jammed hard at range on an unfired handload that I needed to clear to check targets, Fired clear, disassembled, cleaned, inspected, reload with Wolf Gold..jammed without going full battery and impossible to clear without large screwdriver to bolt.

[Gunsnwater]

Are you trimming your brass? Did you get cartridge neck stuck in throat?

[smit308]

YMMV, but I would disassemble and carefully reinspect. Sounds like there is a chunk of something somewhere that shouldn't be.

Smit

[luckyned7]

I double-triple checked everything by eye. Bolt works great without anything loaded into chamber. I can cycle ammo but not every time. Maybe she just done but I doubt it. I found a place that rents go/no go guages so we shall see.

[Hawk]

Do you have a chamber brush? Clean the chamber.


p_084116025_1.jpg