300 blk unburned power in receiver

Hey all!

I am currently loading 220 grain otm bullets with 1680 subsonic and suppressed. I am finding evidence of a decent bit of unburned powder going back into the receiver (upper and lower). I have tried varying my charge weight from 10.9 to 11.6 grains and still getting the yellowed flakes of powder in the receiver. The barrel is 7.25 inches with a pistol gas system and SilencerCo Omega. Does anyone have an idea on how to fix this? Should I crimp more or seat slightly deeper? Currently using a pretty light crimp and OAL of 2.250. I know both of those will raise pressure so I will work up carefully and attentively, but will that result in a better burn?

I have H110 on hand for my 110 supers but haven't tried anything subsonic with that.

It’s not uncommon to have a lot of debris in the lower when shooting suppressed. You can try to vary things to help get a more complete burn, but you may always have some issues. There is a potential to flash over your powder if the bullet seat depth is too long and powder charge is on the lite side. What primers are you using? Is the powder ok. No exposure to moisture or oils ect...

Keep the 1680 for subsonic and the H110 for supers. While people have used H110 for subs, the burn rates for both powders are specifically designed for certain purposes and I have found that 1680 is best for subs and H110 for supers.

I am using CCI 400 small rifle. Would a magnum primer with a hotter burn help? I understand a new load development would be called for.

The powder is good. It stays in its container in a cabinet in a low humidity environment.

I don't get much debris in the lower with all of my suppressed 223 rifles. It is only happening with the 300 blk.

The cci 400 primers are good. You won’t get the same problem with 223 because you aren’t running subsonic. I would bet you don’t have the same problem running H110 and supers in 300blk suppressed. The common issue is subsonic suppressed. Every powder I have tried has the same basic problem. Extruded powders are the worst. Super gritty. It’s something you just have to live with and know is going to happen. It doesn’t mean something is wrong.