Hello! I'm having an issue on my post sample 10.5" AR running on full auto. It will run for 2-4 rounds, then I get a light primer strike. Seems to run fine on semi auto. PArts list below, followed by what I've done to try to correct it:


-Odin Works 10.5" 223 Wylde barrel
-Odin Works adjustable gas block
-Odin Works carbine length gas tube
-Radian Raptor charging handle
-SLR Rifleworks B15 upper
-ADM UIC lower
-Geissele SSF trigger
-Odin Works adjustable buffer (weight is ~6oz right now)
-JP Enhanced buffer spring
-Spikes Tactical BCG

So far I have tried an H2 buffer, I've tried medium to heavy adjustment levels on the Odin Works buffer, and I have tried adjusting the gas from almost completely closed to almost completely open. I've had almost identical results the entire time (slightly better with the gas almost completely open, and while running suppressed).

My first thought is that it is bolt bounce, but I want to know what some of your recommendations would be to remedy this issue. Thank you!

Heavier buffer or adjustable gas.

Does the buffer have room for the weights to shake back and forth? You shouldn't be having bolt bounce issues if you have H2 weights in a properly reciprocating buffer.

You may need to check your timing. If the hole is drilled to far back you may be releasing early and following the bolt down every few rounds.  Alternatively your upper could be sitting farther forward than it should or your carrier trip face could be a little forward.

You could probably bandaid over it with an extended firing pin.

I would put a new H2 buffer in, then swap a new BCG in, then swap uppers and see which one eliminates the failures. If they continue you probably have an issue with the location of your sear pin hole.

The cheap bandaid:
http://www.redxarms.com/product-p/5061.htm

Quarterbore has good instructions on checking the timing of a RDIAS. You can use them to check timing on your conversion as well.
http://www.quarterbore.com/nfa/dias.html

This. I've seen it on an m16a1 and a Dias gun.

BTDT: New Hammer Spring

Light primer strikes like you have are almost always bolt bounce.

I would video it (iPhone can do 240fps), and see if you can see it.

This fixed it for me when I had light primer strikes.

This.

OP you have a lot of variables running all those non-standard parts. I would remove all the adjustable and “enhanced” parts and use standard milspec components that are known to work.

Definitely sounds like a bolt bounce issue.

As already mentioned I’d replace the fancy RE parts with milspec ones and see what happens.

THIS! avoid ALL aftermarket BS parts.My Colts all run 100%.No BS gizzle triggers ect.