SpudFiles

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Hybrid I assume?

A padded, spring loaded stock will give the most recoil reduction without adding extra weight.
I believe .50 cal rifles use springs to reduce recoil, and it apparently works quite well (given they produce upwards of 10k ft-lbs).

Edit: ack! I've been sigged!

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Does that calculation include an estimation for the momentum of the gas?
Well, obviously a good start is a well built muzzle brake, but that's obvious, so you've probably considered that idea.

More weight would also help, but you'd need twice the weight to halve the energy, and a 30 pound cannon would be insanely heavy, and 35 ft/lbs of recoil is still a lot.

Recoil pads and springs don't reduce recoil energy, but they will reduce recoil force (important difference). You'll still have to absorb all that energy, but it won't feel as much like being hit by a train, and it might also reduce recoil distance a little, as your body would have more time to react and start to counter the cannon's movement.

In short, a muzzle brake, and a good recoil stock are a good start.

@Fnord: Well, a .50 BMG round is about that weight, but roughly 4 times the energy (thus, twice the velocity and twice the momentum). But you will notice that something like the Barrett M82 has a muzzle brake as well, is typically fired with a bipod (often from prone), weighs closer to 30 lbs, etc... all of which makes more difference than just a recoil spring.

Springs and shocks would be a good candidate for absorbing some of that energy, as well as a proper muzzle break.
From what Mark tells me, his Mauler produced somewhere in the range of 75lb/ft of recoil energy, and was shoulder fired with no recoil absorption system at all, though not more than a few times a day.

if i were you i would look into some kind of backflow system, like a large-volume pneumatic that fires the opposite direction. mabey like a Coaxial with an electronic pilot.

What about a compressed air shock absorber? If you have the facilities, you could easily incorporate two into a stock.

55 grams = 848.78 grains
most guys shooting the .50BMG are shooting 647grain FMJ/~175grain charge @2710fps.
this is what produces the ~70 ft-lbs of free recoil energy on a 30 lb. rifle(12.3 fps recoil velocity).
a larger projectile would create even more free recoil energy.
if you could keep that same charge and same velocity but use your 55 gram/848.78grain projectile the free recoil energy would jump to ~103 ft-lbs(14.9 fps recoil velocity).
unfortunately the charge has to be increased to maintain the given velocity, once the charge is increased so is the free recoil energy.


that being said,
even the best muzzle brakes only offer a 45%ish reduction at best. this would knock it down to 38 ft-lbs of free recoil energy.
my .338 Winchester Magnum shoots @ 33 ft-lbs. w/o a brake
my .44 Remington Magnum @ 11 ft-lbs.

the average persons comfort zone is below 10 ft-lbs of free recoil energy.
if you weigh less than 150 lbs be prepared to get hurt



on another note: what is the formula you are using to calculate your free recoil energy?

i've always used a formula from the Lyman Reloading Handbook, 43rd Edition.

E = 1/2 (Wr / 32) ((Wb x MV + 4700 x Wp) / 7000 x Wr)2

E = recoil Energy in ft. lbs.
Wr = Weight of rifle in pounds
Wb = Weight of bullet in grains
MV = Muzzle Velocity of bullet in feet-per-second
Wp = Weight of powder in grains.

(this only works with powder)

Edit: thanks ragnarok for straightening out the formula

you could use a system like on the rt-20 which directs the hot gases back through a fat tube on the top http://world.guns.ru/sniper/sn56-e.htm

ALIHISGREAT wrote:you could use a system like on the rt-20 which directs the hot gases back through a fat tube on the top http://world.guns.ru/sniper/sn56-e.htm

I wouldn't attempt this unless you want hot hybrid gas in your face. This would also be wasteful with the limited gases on tap.

I wouldn't attempt this unless you want hot hybrid gas in your face. This would also be wasteful with the limited gases on tap.

but the tube would either be on the side of the barrel or the sight would be on the side of the barrel like on the rt-20 and i think it would be worthwhile doing because it would reduce the recoil massivly.

Another alternative is to add a big silencer near the muzzle and then have a muzzle brake aswell to further reduce the recoil, this combined with a recoil absorbing stock and a bipod should make the recoil perfectly manegable

@BluerussetboyThat formula seems to be missing a set of brackets:

E = 1/2 (Wr / 32) ((Wb x MV + 4700 x Wp) / 7000 x Wr)²

Talking about recoil, I only weigh about 160-170 lbs (never sure exactly how much), and I've fired rounds from HEAL that reach about 12 ft-lbs free recoil energy - and I'm fine with that. I even welcome a moderate kick, it adds nicely to the experience of shooting my launchers, and there's a nice feeling that adds to the cool of making a vegetable cross your garden at half the speed of sound.

I wouldn't routinely shoot something with a recoil over maybe two or three times that because then you start to risk developing a flinch, but I have few projectiles that can generate that sort of recoil, so I should be all right there - at least until I get another craving for more pressure.

@ALIH... etc: That wouldn't be that much different to a muzzle brake in terms of recoil reduction, but it would certainly cut performance big time.

But if you put the vent in the barrel to feed the tube very close to the end of the barrel? and after further thought would a supressor attachent before a brake actually increase the felt recoil because it would reduce the effectiveness of the brake?

Ragnarok wrote:@BluerussetboyThat formula seems to be missing a set of brackets:

E = 1/2 (Wr / 32) ((Wb x MV + 4700 x Wp) / 7000 x Wr)²

guilty of c/p. i wasn't sure of how to post/format the formula online. plus there was a couple of IPAs involved.

thank you

Don't worry about it, it was no problem at all.