Took my fresh sbr build out this weekend and it was a massive failure.  First few shots were good. One shot,  clean x5, then two 3 shot stribgs to test feeding, bolt lock, etc. That was all fine. After that i through a 30 in and had 4 fte. I took it apart, lubed it, inspected, no obvious issues. I switched magazines to pmags, and through a slidefire stock on for my buddies to shoot and that's when it really went to shit.  It would run about a 5 round burst, then id have a dead trigger (hammer was up against the bcg). And the cartridge would NOT fire, bcg wouldnt come back.. it was locked in there tight. I finally said forget it and throught it in the bag.... after i hammered the bolt back to remove an unfired round.. where it left the actual projectile locked in the chamber.

Ive tried a different 16" upper, with no issues.

The setup is as follows:
Anderson lower and lpk
H2 buffer
10" barrel, carbine gas, parkerized non chrome. 223 wylde
Psa premium bcg
Bcm gas block, dimpled barrel, staked screws and pinned. It is straight,  and did not move.
Cmmg gas tube.

The hammer follow (i think that's what it is called) could indicate the need for an h3 buffer, right? Why the heck is the ammo sticking like that though? It was factory .223 ammo, brass.

Please, any help?

Brand of barrel?

Slidefire stock led to hammer following the carrier closed. Fresh round got the bullet lodged in the rifling making it hard to pull the bcg back.

It's often times easy to outrun the carrier with a Slidefire/bump stock. I keep a light weight carrier in my bump guns so the action cycles fast enough.

10" 5.56 barrel with pistol gas? Normally those are carbine gas.

What profile is your barrel? Generally proper buffer weight is determined by barrel mass. H2 should be plenty unless your running a 16" heavy barrel(or heavier).

Bear creek. Not a liked name i know,  but ive run 6 of em so far and been happy. Its a range toy, not a life defense rifle.

Hey,  thank you so much for your input! You're absolutely correct it IS a carbine,  so sorry!
https://www.bearcreekarsenal.com/barrels/ar-15-barrel-10-5-contour-barrel-w-1-7-twist-223-wylde-parkerized here's the barrel.

You need a set of headspace and throat gauges.

That's the only solid way to figure it out.

It sounds like short headspace/throats as a chambered round should never touch the rifling.

Beyond that, you are getting hammer follow.  Check your lower...disconnector and spring.

You're right, i do need those.  Thank you for the response

You also need to repeat a few English classes. I believe 3rd-8th grade should help.

This is a Technical Forum.  Cut that out. - Old_Painless

Did your autistic ass think this was gd? This is a tech section. If you cant help, move along.

You too. - Old_Painless

How clean is your chamber. If it has any residue from the cosmoline type crap it can cause a round to hang up. It heats up and acts like a glue and locks the round in place therefore locking the bolt forward. It doesn't take much.

what kind of factory 223 brass? Have you tried anything different? Are you seeing chamber markings on the extracted brass?

Have you tried hand cycling about a dozen without firing? If its still is sticking it may be a tight chamber or something gunking it up. Tight chambers sometimes open up after about a 100 rounds. I would take the slidefire stock off and get it running before playing around with it again. You are probably out running the carrier with the slide fire. LW carrier will solve that issue.  Hope that helps but if you have more than one ammo manufacturer and look at the extracted cases, that could tell you a lot.

Barrel profile has nothing to do with buffer weights. Heavy buffers are used to slow the BCG. If your gas port is oversized, you added a silencer, etc. Can also be solved with an adjustable gas block or adjustable carrier (gemtech).

What brand ammo?

Is your BCG lubed properly?

Does your lower function with other uppers? Your upper function on other lowers ok?

Get it to run right first and then swap over to the slidefire, but most problems are gas related, so either an AGB/carrier or heavier buffer may help you out.

Your experience at not being able to extract a live round of 55gr FMJ is completely predictable based on your choice of barrel.

The Wylde chamber is an interference fit at the throat. Certain bullet styles will actually be impressed into the freebore (not the "rifling" as others incorrectly assert). This is by design, as the Wylde chamber is designed as a specialty chamber for long range precision shooting, not high volume bumpfiring.

With the hammer down on the bumpfiring, it is sometimes just due to pulling the trigger before the bolt carrier has had time to fully seat, or possibly even a bolt bounce timing issue. If you have examined the fire control group, and it passes the basic function checks (you did function check it, right?), and it functions normally in live fire, then it's just a timing problem with your bumpfiring.  Using an H2 buffer with a 10" barrel might actually be slowing the cyclic rate down too much, you might need to try an H1 or even a carbine weight buffer.