The shotgun shell uses less powder than a typical rifle round, though the characteristics of a shotgun make handing the resulting propellant gasses more difficult.Chemically, modern gunpowders are comparable in overall chemical energy content, but differ radically in their burn rate characteristics. Pistol/shotgun powders burn fast and develop maximum pressure much more rapidly than rifle powder.
So, by weight, a pistol or shotgun powder charge will develop
roughly the same uncompressed gas volume that a rifle powder will.
(Though it will be at different pressures and temperatures when it reaches the supressor)
12 gauge shotgun, 3" magnum, 12x #00 buckshot = 25-29 grains of powder
.45 ACP pistol, 230gr bullet = 5-7 grains of powder
7.62x51 NATO, 168gr bullet = 40ish grains of powder
300 WSM, 210gr bullet = 60ish grains of powder.
The reasons a shotgun needs a slightly larger suppressor, relative to a rifle are;
- Larger bore diameter, larger fraction of the gas wants to keep going through that large hole
- Lower gas pressure relative to a rifle, less pressure to drive the gasses into the suppressor baffles
(to put it in empirical terms, a shotgun makes a large deep BOOM - a rifle makes sharp medium BANG)
And, unless you're using a bunch of heavy shot moving below 1100fps, you're going to be making a ton of noise with your shot making sonic cracks from moving near mach 1.0.
The magic number for a suppressable 12ga load would be around 12x #00 buckshot, with a
redacted powder charge, moving those 12 rounds of shot at 900fps.
To put it another way, that's about the same as 12 shots from a 9mm pistol with one pull of a shotgun trigger.
Last edited by rdx-fx (2010-06-23 14:15:47)
