Powder for 300 Blackout

[Rich22]

Since it appears I may soon be able to trade for some SRP I need to go about getting some powder together. I am looking for a powder that will work with both Supersonic and Subsonic. 95% of the projectiles will be Cast Lead but I do have quite a number of Jacketed bullets I was lucky enough to get a killer deal on some months back. Have not decided on a mold for the supers yet but got the 247gr NOE mold for the subsonics. Looking to get some good performance out of this but this will be my first rifle loading experience so to say I will be taking it slow will be an understatement.

Thank you

[felix]

So far, the only choice of powder for all auto functions is from the various lots of the WW680's, which are WW680, AA1680, WC680, H116, etc. This is not a beginner's cartridge with an auto-gun to load for. More powder variation would be acceptable with the Wilson Combat gas block installed on the barrel. ... felix

[cutter_spc]

Take a hard look at Alliant Power Pro 300-MP for your super needs. I beleive this to be the best powder out there for the black.

[felix]

Super needs are satisfied with several powders in that said speed range. However, the selection problem is making the boolit of choice physically chamber without hiccups and have the bolt remain open at end of the stack, all when the boolit is loaded intentionally below the speed of sound. Changing the powder speed is more costly (and risky) than installing a variable gas blowback device that accomplishes the same thing. ... felix

[Moonie]

AA1680 is the default and recommended powder for subs in 300. You can also use RL-7 and AA5744 for subs and supers. I load only supers now and use H110/W296.

[Frozone]

Had good success with RL7 today; 12gr for ~1060 fps, deviation was higher than I would like 1041 -> 1096 - that's in a 10" barrel.
I think 11.7 should about perfect for speed but I don't know if the SD will improve - i rather doubt it.

DID NOT like the W296 - @ ~1400 fps deviation was all over the board > 170 fps.

[Moonie]

Had good success with RL7 today; 12gr for ~1060 fps, deviation was higher than I would like 1041 -> 1096 - that's in a 10" barrel.
I think 11.7 should about perfect for speed but I don't know if the SD will improve - i rather doubt it.

DID NOT like the W296 - @ ~1400 fps deviation was all over the board > 170 fps.

Has your brass been annealed since forming them? I've read that can make a huge difference in SD/ES due to boolit pull differences.

[Frozone]

Has your brass been annealed since forming them? I've read that can make a huge difference in SD/ES due to boolit pull differences.
It has been annealed, it's the first firing since the annealing was done.