Harder recoil with lighter main spring?

[elenius]

I just got my kimber back from the gun smith. Had a trigger job done, and he changed the main spring from a 19 to 17# one. I took it to the range, and it seemed to me that recoil was a bit sharper. The gun was pushing into my right hand more.

Does this make sense or am I just imagining things? I can imagine that a heavier main spring decelerates the rearward motion of the slide more, and therefore makes recoil softer. Should I change to a lighter main spring to compensate? (I have a 13# in now). Will a shok-buf change how it feels? (I was going to put one in anyway)

[Canuck-IL]

It makes sense - the slide has to overcome the hammer to recoil and you reduced the resistance provided by the mainspring. You should try a minimal bevel FPS - get the oversize one from EGW and stone/sand/file a *small* radius on the bottom. This lowers the slide impact point on the hammer and thus increases the resistance. You can balance the mainspring, recoil spring and the FPS to significantly alter the feel.

/Bryan

[HSMITH]

Shoot it for a while and learn the new timing, it is a faster recoiling gun now, but that just means you will be able to recover and shoot that much faster. Been there and done that, from one end of the spectrum to the other.

[bountyhunter]

There are two shock impulses which make up the recoil in an auto (only one in a revolver). In an auto, there is a pulse at firing and one when the slide bangs into the frame. In most autos, the first impulse is higher, here's why:

The slide is amoving mass which acts as a recoil "absorber" because energy is expended to make it move, and energy is stored in the recoil spring. In other words, the more easily the slide can unlock and move rearward, the lower that first shock impulse is. In most stock guns, the hammer spring and slide mass that it must overcome to get moving is large enough that the first recoil impulse will be larger than the one when the slide hits the frame.

In most cases a lighter hammer/recoil spring makes recoil feel lighter, since it is reducing the first peak (which is usually higher) by letting the slide get moving with less applied force. However, if the recoil spring is too light (and the slide is really banging into the frame) the second peak may dominate and lighter recoil spring makes it feel worse. Comp shooters select springs to try to balance out the peaks which results in the gun shooting flatter (less muzzle rise).

A shok-buf probably won't do much, bit one of those variable rate "recoil absorber" guid rod/spring assemblies might if your slide/frame impact is dominating the recoil feel.

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Edited June 22, 2007 by bountyhunter