Subsonic 6.5 PRC loads?

Look up subsonic load data on Hodgdon's site. They have a ton of 300 blk loads and 4 308 win loads. I have shot 3 rounds of the 190 gr sub x in a 308 with a 1:10 twist. It seems stable but I am gonna shoot more before I run it through a suppressor.
I would say NO on the 6.5 PRC. To much case volume and to light of a bullet.
 
What powder and charge are you using for your 308 load?
Hands down, the best powder for subsonic rounds in .308 that I have found is Herco (We have shot 1000's of subsonic rounds and have used about a dozen powders looking for something good). I would start with 8 grains. Herco is one of the bulkiest of the shotgun/handgun powders and burns clean. There is no need to top the case with filler, just load and shoot. A tremendous benefit to accuracy in SS rounds is neck sizing only. Subsonic rounds do not develop a tremendous amount of pressure* and one will get several firings before needing to FL resize. Additionally, 7 grains of Herco for a 300 Sav, and 6 grains for a 30-30 or 7.62x39. I have used Trail Boss, it is dirty and the accuracy is not there.

A word of caution, be sure to double check your charges and powder level (use a flashlight to look in the case). I would recommend charging a case, then seating a bullet to eliminate any overcharge possibilities.

*The Lyman Reloading Handbook, 46th Edition, states that a 308 loaded with 15.5 grains of Herco using a 151 gr cast bullet develops 39K CUP.
 
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