300BLK subsonic load w/190gr SMKs

[Wolf762x51]

Hey guys! Just put together an AR pistol in .300blk as my "truck gun", 9" barrel with carbine gas system. Around the same time I happened to snag some 190gr SMKs at a yard sale so now Im wondering if anyone knows a good powder so start with thatll hopefully cycle the action with my SDN-6 mounted. Anything helps, thanks in advance! Also have some 110 Barnes Tac-TX for close-in deer hunting so anything for those would also be appreciated.

 

[Supersum1]

Everybody swears by AA1680 for subsonic 300blk. I’ve run it out of my 10.3” pistol with 200gr Berry’s and had no issues cycling even with an H2 buffer. Think my load was 10.5-11.0gr, have to check my book.
Also have a lb of CFEBLK I’ve been meaning to try out, just haven’t been loading for 300blk recently

 

[spife7980]

Cfeblk

it’s in the name

 

[alamo5000]

Hey guys! Just put together an AR pistol in .300blk as my "truck gun", 9" barrel with carbine gas system. Around the same time I happened to snag some 190gr SMKs at a yard sale so now Im wondering if anyone knows a good powder so start with thatll hopefully cycle the action with my SDN-6 mounted. Anything helps, thanks in advance! Also have some 110 Barnes Tac-TX for close-in deer hunting so anything for those would also be appreciated.

I have used Shooter's World Blackout powder to great success with 190 grain Nosler bullets.

That said I bought a box of 1000 of them and found that grain weight of bullet quirky to load subsonics in. I probably won't buy any more of them unless it's a fantastic deal or something. In my experience with 190 grain bullets (if you are loading strictly for subsonics) is that the list of powders that work well is quite a short list. The main problem I had was a lot of powder shift which would create huge variations in velocity.