300BlkTalk

First thought is magazine, or the bolt is not traveling back far enough for the magazine to feed. You can drop down to 2-3 rounds to reduce weight on the magazine spring and see if it helps.

What's lifting the bolt latch, shouldn't be the follower?

Or is it catching on something else?

For what it's worth, its a step in the right direction. you might be under gassed now. Really should not cycle with a rifle buffer.

Its odd, it will strip another round off the mag, almost chamber it, then the spent case winds up back in the chamber sideways (mouth or head).

You said with the A2 lower the bolt would hang open and you had to release the catch. Normally the follower at the bottom of the magazine lifts the catch.

What is the bolt stopping on with the A2 lower?

There is a good chance with the original lower, that he bolt is not strong enough to hold onto the base of the spent casing and its dropping it on the top of the next round. When its over gassed, it tries to pull the fired round out when it is still tight in the chamber and makes it worse. Generally you can see some claw marks when it pull off the base. If there is no fired case left in the upper with the A2 stock. this makes the most sense.

Then try to figure out the locking back issue, and that may very well be under gassed. Knowing buffer weights would be very helpful.

ok, so I'm back to playing with the 300 black out. I don't think I have a scale that will weigh my buffer, unless my reloading scale will take that much weight. I managed to take a couple of "slow motion" videos one handed with my S8. best I can tell the brass is hitting the deflector with its mouth, then hitting the front of the receiver before bouncing out of the way of the bolt. some dwell time in the receiver before it is clear of the bolt. if anyone has a good free site to post vid I will share. been messing around with powder and bullet combos, found Hornady 110 with 17.4 gr of H110 cycles well (2 in 100 = fail) once I got up to 18. something she starts eating poo more regular.

Buffer weight is 84 grams or 2.9630128038 OZ. Should I go with more weight, slow things down a bit? brass is currently deflecting forward to the 3 o'clock when cycling, some just land on the bench. Found some buffer's on https://www.ar15handguard.com at a nice price, anyone ever shop here? again the set up is a 16" with pistol length gas system. the more I read this sounds odd, maybe suppressed this makes sense?

Buffer is way too light for pistol gas and even worse for pistol gas in a 16” barrel. Move to at least an H2, maybe an H3, or as suggested before turn you gas all the way off and work it up until it just cycles.

Basically your bolt is traveling too fast for proper ejection and feeding.

Suppressed will make it even worse as that add even more speed to the bolt.

So, H2 or H3? should I go for the H3 and sub one of the standard buffer weights if it is too heavy? Gas block is not adjustable unfortunately. any experience with Omega Mfg Inc H-3 Series Heavy Buffers. not so much customizable, one solid tungsten weight, gunbroker has them for $19, 5oz. AR handguard has a 4.9 OZ Heavy Buffer Mil-Spec Carbine Stock Buffer AR15 223 5.56 for $10.

your plan of getting a h3 and if needed make a h2 and a h1 by swapping weights between your two buffers is a solid plan. if you do make sure you dont forget to put the little spacers in between the individual buffer weights.

i would not go with a solid weight - part of what makes a buffer effective is the fact that the weights move around inside the buffer. its like a dead blow hammer effect.

it helps prevent bolt bounce from your buffer smacking the rear of the buffer tube on you.

hth

wasn't in the description but the one from AR handguard is also solid buffer weight. guess ill find out how it works tomorrow. got a mill spec receiver extension with 4.9oz buffer and new spring for $23, fit and finish is good, so their is that...

maybe better? bought a 300 Pmag Maybe something to do with it? should probably start looking at AGB for this thing? seems like it would be hard to adjust under the handguard (pistol length gas - 15" handguard)