I’ve been toying with the idea of getting a .300 Blackout upper for my Sig M400 so I can shoot 220 grain suppressed rounds. I also have a CMMG Banshee in 10 mm that I’ve been loading 220 grain subs for (and I already have the proper suppressor, a Rugged Obsidian) that is very quiet and pretty easy to keep the rounds subsonic with the 220 grain powder coated projectiles that I’ve been loading. The KE at the muzzle is almost identical at ~520ish ft.lb. for both cartridges. The main advantage to the .300 Blackout, as I see it, would be greater range for the more aerodynamic bullet profile over the big wide 10 mm flatpoint.
My questions are:
1. Which should be quieter, given similar chamber pressures, muzzle velocities and muzzle KE?
2. Would the smaller exit hole of the .300 keep it quieter than the .15” larger exit hole of the Rugged Obsidian?
3. If I can find an end cap with a .40 exit, would it be worthwhile, or a waste of money?
4. And lastly, what would be the effective range of each cartridge at subsonic velocities?
My questions are:
1. Which should be quieter, given similar chamber pressures, muzzle velocities and muzzle KE?
2. Would the smaller exit hole of the .300 keep it quieter than the .15” larger exit hole of the Rugged Obsidian?
3. If I can find an end cap with a .40 exit, would it be worthwhile, or a waste of money?
4. And lastly, what would be the effective range of each cartridge at subsonic velocities?
