Thread: New rifle, scope question

Originally Posted by gadgetman

This relativity only applies to light projectiles going 3x 10⁸ meters per second. For what we're dealing with we just go for 1/2 mv².

I was trying to say that the energy the bullet has leaving the muzzle is the main determinant of recoil going the other way. The reason the rifle is slower going rearwards is that it is 300 to 400 times heavier than the projectile thus reducing speed. If he wants lighter recoil then choosing between identical models of 308 vs 7mm08 (say a T3) then the weight difference between the rifles is negligible, and the energy of the bullet at the muzzle is close enough to identical between the calibres, thus there is almost no difference in recoil between the two. To make any significant drop in recoil, he would either have to sacrifice speed / energy by using lighter loads or make the rifle heavier to slow the recoil.

As a side note, I use the term slow the recoil because the actual amount of recoil in a heavier rifle scenario would actually be the same but the slower transfer of energy to the shoulder will make it feel like less recoil.

Short and sweet. Recoil difference between 7mm08 and 308 is close enough to not matter.