Re: .308 subsonic
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: normbal</div><div class="ubbcode-body">I did the Trailboss calculation based on bullet/case volume.
Here:
http://www.imrpowder.com/PDF/Trail-Boss-data.pdf
My estimated weight of TB was 10.85. I backed off to 10.5, 10.7, etc, to 11.1 grain by 0.2 grain intervals.
Using a 180 grain Sierra RN bullet over Federal FLS/annealed brass with GM210M primers out of a 26 inch barrel Rem 700 PSS with 12" twist 10.7 gns is giving me
1041 fps, with an SD of 10.5. Using an SRT shadow can, too. VERY quiet, all you hear is the bullet impacting the berm. No keyholes at 100 yds.
With today's temp of 66.6F, Humidity 63% and Pressure of 29.99", mach is 1124 fps giving a muzzle energy of 441 ft-lbs.
This is good.
I'd previously done this with bullseye powder based on articles from Finland and other data found (about 8.2 grains), but with a MUCH wider SD.
This is fun. Can't wait to get my suppressor for my .338 LM and play with this.
<span style="font-weight: bold">What practical use is it?</span> None yet. But hunting with suppressors opening up in a lot of states, there's still hope. A .338 bullet at 300 grains has 735 ft-lbs of ME. And no other deer get spooked. You could take out a heard before they'd figure out what's going on.
<span style="font-weight: bold">Besides, it's a hobby. It's not supposed to be practical.</span>
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I have found it VERY Practical when taking out stray dogs right where they drop and not wanting to alert my neighbors of any foul play