300 Blackout w NOE 311 247 powders?

[mstarling]

Guys,

I finally got the paperwork completed and the lower marked so I could build my upper with a 8.5" 1:7 300 BLK CMMG pistol position gas bbl. Cute little fella. Intended for subsonic only use.

Also have a 16" 300 BLK with a pistol position Paladin barrel.

Have an NOE 311 247 plain base mold and have a supply of projectiles cast in WW and sized to .309".

Found that the 16" rifle makes subsonic velocity with abt 8.3 gr of 2400. Burns pretty clean. Have not had much chance to fiddle with it and the cast bullets much. 220 SMKs and 225 Hornady OTMs work really well and kill deer like a champ as these bullets upset on impact.

Have you had success with feeding of this projectile subsonic? Anyone try 2400 with the 311 247? What other powders have proven to be useful?

Thanks,

Mike

[Wayne S]

Not an AR but a 1-8 T/C 15" bbl. so I can't help with the feeding, besides 2400, I've played with
# 9, H-110, and VVN 110, all on the 8.0 to 9.0 gn range

[winchester85]

what kind of accuracy are you getting with the sierra 220gr?

i have been struggling with subsonic accuracy.

[mstarling]

The 16" is giving me sub MOA groups with both the 220 SMK and the 225 gr Hornady OTM with or without a suppressor. Barrel may be part of the key though ... was made by Paladin Machine Services from 1:8 SS Douglas stock. Found that 2400 is a good powder for my application.