Quietest/accurate sub sonic caliber

Which is the quietest suppressed sub-sonic caliber? The .308 or the .300 I have a .300 but thinking about moving to .308 and maybe even the
Savage model 10 with the suppressed barrel. I'm also thinking the .308 might be slightly more accurate a little further out. All my setups are 150 yards or less.
okiehuntr

Accuracy will be more a function of the gun with the ammo than the caliber. With subs u have an upper velocity limit so not much room to work with finding accuracy nodes without going even slower. With the 300 Whisper/BO having a lot less case capacity and a Sub Sonic load filling more of the case I would think you might get a little better consistancy than with the 308 but that is a guess since I have never messed with the 300.

Data for Trail Boss

Just some fun facts on an interesting powder. YMMV but the first page holds a "rule of thumb" step that in Trail Boss's case holds true for any cartridge. In this powders case because of it's doughnut sized structure it fills a HUGE amount of volume with little powder. If you are familiar with some of the cases on pg. 2 look at the grain weights of the loads.

I have loaded SS stuff with TB in the past, .223/5.56 ( no it won't cycle the bolt in semi's but in bolt guns it's a hoot.) and 6.8 SPC. Super quiet (by ballistic standards anyway) with out a can. Had a few guys worried at the time I was shooting squibs....

Shooting subs with 300 blkout and 308 are going to be almost exactly the same, same bullet at the same speed. The only difference is barrel length and twist. Faster powder, faster twist, shorter barrel 300blkout. Slower powder, slower twist, longer barrel 308 win= the same