Don't forget Sprinco for springs!

I forgot how good they are. Fast inexpensive shipping. Good stuff.

Thanks Alan!


sprinco.com

They must be good.  They are not springs to them.  They are "recoil management systems."

Ratings rule of thumb?

I know, " it depends" but what are you using as a fct of load level?

3.5 BE feel nice with a 10# spring; doesn't eject too far, reliable cycling.

For 3.7, 4.0?  Etc

Bet Ashley has an answer!

Dunno if I have an answer.... but...

The general equation for recoil in guns is
Momentum of recoiling parts = momentum of ejecta (bullet and gas)

If the bullet has a velocity of 700 fps and weighs 200 grains, and weight of the recoiling parts is 1 pounds, Then...

Me X Ve = Mg x Vg so Vg = Me/Mg X Ve, in this case Vg = 20 fps...

But what about the powder... at these masses, it becomes “engineering noise”. So increasing powder increases bullet velocity far more than the increase in ejecta momentum. Like about 25 fps per 0.2 grains of powder...

Also consider that a 1911 recoil spring cannot absorb the energy of the slide. If the slide has a velocity of 20 fps and E = 1/2 Ms Vs^2!
Then Es = 0.5 X 1/32.2 X20X20 = 6.2 foot pounds or 74 inch pounds. The energy that can be stored in a spring is its rate times the deflection. A 1911 spring rate is about 2.8 lbs per inch. (This is a 16 pound spring). It would need about 2 feet of recoil spring to stop the slide. The hammer and the other mechanism slows this process so slide velocity is maybe 3/4 this, but the recoil spring can’t absorb much of this energy.

The best approach is to add mass to the slide in the form of an optic. That slows the slide down and cutting the slide velocity to 3/4 of the original cuts the energy down by almost half.

All this said,