Calculating damper size for 3502 ft-lbs rifle recoil

[livinskey]

Hi ,

I am making a shooting rest for my high power rifle and I would like to have a damper take most of the recoil energy so that the shooting rest doesn't move back or up when shooting.

I attempted to calculate what damper would be appropriate for this but I am getting results that don't seem realistic. For example, according to my calculations, a damper that is rated 100lbs and has a stroke of 7inches would only absorb 1.6% of the muzzle energy. A damper that is rated 250lbs and has a stroke of 17 11/16 inches absorbs 10% of the muzzle energy? I must be doing something wrong...

Here are some numbers:
Muzzle energy (of the projectile) 3502 ft-lbs.
Rifle mass: 8 lbs.

Questions?
What size damper should I use?
How much of the muzzle energy actually goes into felt recoil?
What is the formula for multiple dampers and springs connected in searies or parallel?

Thanks

 

[Drakkith]

I don't think your muzzle energy will be 3500 ft lbs when calculating the kick of the rifle. A bullet weighs very little and will be accelerated to a very high speed, while your rifles weighs many many times that at 8 lbs. I don't know, but perhaps it is 3500 divided by the weight of the rifle??