300 Blackout load not rechambering

[suffering4hope]

I started loading a Hornady 208 grain a-max with 4227. Got all the way up to the max load, from the IMR load data on web, which was 10.3 grains. Could not get rounds to rechamber. Has anyone had this problem before?

 

[krw]

My 300 Blkout shortstrokes sometimes. It brings the bolt back far enough to eject fired rd but does not pick up new rd out of the mag. try cutting a couple of coils off buffer spring to lessen the tension to let bolt come back farther. Once I got a 300 Blkout I was not near as impressed as I was hoping I would be. AR platform makes too much noise suppressed and 300 Blkout does not have enough oomph when full throttle loads are used. I like suppressed bolt guns. To each His own. Hope this helps. krw

 

[suffering4hope]

My bolt will go back far enough to eject spent brass but won't load new round too. I am using a DPMS upper with a Colt AR lower. Do I need to try a different powder or go up a few tenths over max?

 

[Pinecone]

If it not picking up a fresh round, try a lighter buffer or buffer spring.

Also a lighter weight carrier might help (Colt neutered carrier or one of the light weight ones).

What gas system? A local gunsmith states that you need a pistol length gas system to make .330 Black work reliably.

 

[pyrofx]

Had the problem with carbine gas system . Only way subs worked was with AA1680.
Went to a pistol gas and cycles with almost any powder.
If carbine , redrill barrel to pistol length and use an old gas block to cover the old hole. My port is .093 in dia.
Greg

 

[BusterB]

Also when you are testing loads only put one in magazine at a time. If the rifle locks back it is stroking enough, if it doesn't lock back you need more pressure. The ways to get more pressure are use more or different powder, open gas port with drill press, or shorter gas system. I don't recommend modifying springs or buffers unless there is a real special occasion.