What 300blk powder do you use for subsonics?

[MR T]

S&W MP15 300blackout
I have been using h110 powder for my 300blk because that is all that was available at the time. Been wanting to load some subs that will consistantly cycle but wanted to know what loads other people are using. Any info or advice is appreciated. Thanks

 

[wby mag]

I dont have the load info in front of me but AA5744 works pretty good for subs.

 

[BountyHunter]

H110 works great on everything from 240 SMKs to 125 Btips in my two whispers and one blackout.

 

[MudRunner2005]

I've read up on several loads, and a lot of people use H110.

 

[azsugarbear]

I have 8 lbs jug of 'Lil Gun' on hand. At 7-8 grains per subsonic load, that could very well last me a lifetime.

 

[MR T]

I have 8 lbs jug of 'Lil Gun' on hand. At 7-8 grains per subsonic load, that could very well last me a lifetime.

Lol, does lil gun cycle your subs well? My gun will eject but doesn't push the bolt back far enough to grab a new round out of the magazine.

 

[azsugarbear]

When I built the rifle, I purchased and installed a variable gas block. It has two positions that allow differing amounts of gas volume into the tube. Full or supersonic loads utilize the position with the small hole because there is a large amount of gas being discharged. The subsonic position has a larger hole that allows more gas into the tube so that there is enough gas available for the bolt to completely cycle using subsonic loads.

 

[Wyo7200]

My advice, test the loads a little below the temperature of which you plan on using them. Doing so will ensure that you stay subsonic through the hotter temperatures, when the air is less dense.

Speed of sound calculator

 

[idaho elk hunter]

IN A AUTO such as yours, 1680 for reliability and cleanliness. For the quieter load in a Auto, 5744. In A bolt gun, use Trail Boss, 245 gr Missouri lead, hex coated, and Carolina brass. A thumper for sure. There is none quieter. SWR Spec War.

 

[snox801]

Hard to beat h110. All my 300s like it. Ive tried lilgun but it is a bit dirty compared. Didn't pick up any noticed velocity. My .458 on the other hand picked up alot of speed so lil gun has a purpose.