Recoil Spring weight

[bret]

I bought a Kimber Custom II for my son, it is new but had the worst trigger and stiffest action I ever felt.

On one if my STI Edge .40'a I put a Brazos Custom trigger in it, so I put the old trigger and mainspring from the STI in the Kimber, now the trigger is better, but the recoil spring is still very stiff.

What is a good weight spring to try?

I was thinking 14 to 16 lb at the most.

I think the main spring is 17lbs.

[BASE772]

For 170 PF loads I use a 14# ISMI.

[bret]

For 170 PF loads I use a 14# ISMI.

Thanks

[Red magnum]

I'm using a 15lbs spring running at 175 PF

[Quack]

I have a 12.5# recoil with 15# mainspring in my 2011

Edited August 4, 2015 by Quack

[Doc10mm]

I'm using 14# as well and I use a small buffer from EGW.

[BASE772]

Note there is a huge difference between Wolff and ISMI springs.

A 13# Wolff is heavier than a 14# ISMI. A 12# Wolff seem almost like a 14# ISMI. And in my experience the Wolff seem to lose their strength faster than the ISMI also.

[Postal Bob]

First, your trigger pull improved significantly because you put in a 17lb mainspring. Kimber normally come with a 21lb mainspring, and 16lb recoil spring. The custom trigger probably had very little to do with the change.

Second, I'm assuming we're talking about a .45 acp? In my Kimber, with the stock(21lb) mainspring, and 168 pf loads, I use a 15 lb Wolff variable spring. But if your using a 17 lb mainspring, you might want to stick with the 16lb recoil to keep muzzle rise from being too much.

Also, keep in mind the gun is new, and will be extremely stiff until you put 500+ rounds through it. My Kimber was stiff as a board at first. But now it's as smooth as glass after several thousand rounds.