Force Transferred to Recoil Spring

Since many variables are unknown, this should be a measured result instead of a predicted result. You're using a spring so the elasticity laws apply.

Also need to know the muzzle velocity and the mass of the projectile.

its for a 55-grain projectile at 2700 fps from a 7 pound rifle.

81.2% of the energy is transferred to the recoil spring. Some is absorbed by the mass of the weapon and the rest is lost to friction and a small amount to heat.

If the weapon is fired parallel to the ground.

Pointing the muzzle up, or down, will have some effect on this. That's easy enough to calculate.

Next question?

Use kinetics analogy or impact and momentum perhaps, plus chemical potential of the gun powder.

I'll take a Mini-14 or the old M-14 over that new junk any day.

So is that homework or are you working for a clandestine group?

There is no way I can see that anyone other than a professional working is likely to be attending to that sort of a problem. It is clear that you have no idea of the nature of the problem you are looking to solve.

There are some other points that may need to be looked at, muzzle brake - how effective is it for example. Do you even have one fitted?

Depending upon the design of the reloading system (I am assuming automatic reloading, but HOW it works is important), that can have dramatic effects on how much recoil is felt.

Certain fully automatic weapons for example, in full automatic, actually "pull" the shooter in the direction of the fired bullet!!! The Bren is a good example ofthis.

I found the Bren recoil even when using it in single shot .303 mode (I never fired the .762 version, though I did maintain them!) to be far lower than the RE .303 using exactly the same cartridges, but no automatic, to be far lower, possibly helped by the weight difference as well of course....

The RE .303, was bolt action reloading. No muzzle brakes on the military version anyway....maybe some private ones? It could have done with some recoil removal, I hated them, kick like a wild mule.....

What about this?:-

Mako-defense-recoil-reduction-stock-fo-M4