Originally Posted by Nomercy448

The short version: Suppressors significantly cut actual recoil, not just noise. Can't do one without the other - noise is reduced by reducing the velocity of the propellant gases as they release from the rifle and slowing those gases reduces their contribution to recoil.

The long version for those interested: A suppressor "quiets" the muzzle blast by slowing down propellant gases, which also reduces recoil. Brakes and suppressors reduce recoil differently: Brakes redirect the gases, which actually creates a partial forward force as the gases slam into the front edges of the ports and are redirected at high velocity. Suppressors expose the escaping gases to a tortuous path, slowing ("letting down") the gases to reduce the muzzle blast as they reach atmospheric

Most guys never consider how much our charge weight contributes to recoil, but it's relatively substantial. For those not familiar with the formula for recoil velocity calculation:

Recoil Velocity = [(mass of bullet x velocity of bullet) + (mass of charge x velocity of gases)] / mass of rifle

*For those keeping track, this is nothing more than the law of conservation of momentum, solved for velocity of the rifle.

For a conventional bottleneck cartridge, SAAMI lists the STANDARD for unsuppressed propellant gas velocity is 1.75 times greater than that of the bullet. So in a 30-06, running a 150grn bullet at 2950fps over 50grns of powder, if you consider how much recoil velocity comes from the bullet and how much comes from the powder (converting grains to pounds mass to scale the numerical results, otherwise not worrying about weight vs. mass):

Bullet momentum = 150grn x 2950fps / 7000grn/lbm = 63.2 lbmft/sec

Prop Gas momentum: 50 x 1.75 x 2950 / 7000 = 36.9 lbmft/sec

Total = 36.9 + 63.2 = 100.1 on the rifle.

So a touch over 35% of a rifles recoil is from the gases (in this case). Slow those gases down to 75% of the bullet speed instead of 175% and you reduce total recoil by 21%.

Another way of looking at it - because the propellant gases are traveling faster than the bullet, even though they are only 50grns, act as if they were an extra 87grns of bullet weight. We're all familiar with what shooting more bullet weight at the same velocity means in terms of increased recoil. By slowing the gases down to 75%, those 50grns only act like 37.5grn of bullet - a 50grn swing compared to the unsuppressed contribution. So comparing a suppressed vs. non suppressed 30-06 is VERY similar to comparing that 150grn 30-06 to a 100grn .243win.

Not to mention - you're adding usually 3/4 - 1 lb of rifle weight by adding a suppressor, which slows recoil velocity by another ~10%, AND positioning it at the muzzle helps reduce muzzle rise as well.