300 AAC subsonic loads

[Speedrdr]

Can anyone recommend a subsonic load that will cycle the action? Have a 16" upper with a pistol length gas tube. I am told that trailboss is not an acceptable powder choice. Thanks in advance

 

[Chainsaw.]

IMR4227 is a good powder for 300 subs.

http://www.hodgdonreloading.com/data/rifle

 

[berettaprofessor]

10 grains of IMR4227 reliably cycles my 300AAC with an 18" barrel; Load is a 208 Hornady XTP with an OAL of 2.250 but it is not quite subsonic (1138 fps). I haven't tried loads under 10 grains yet.

 

[disseminator]

10.5 grains AA1680 under a 220 Berrys works in mine no problems.

 

[Elkins45]

2400, AA#9, 4227 have all worked for me. So has Power Pistol in my 10" gun.