OK what happens when you change springs?

I.E. Recoil spring what happens with lighter/stiffer?

Mainspring , lighter/stiffer?

It depends on a number of factors. For example, changing the recoil spring to the lighter pound weight is used for the light loads for bull eyes competition. Going to a heavier weight spring to control the slide velocity on hot loads.

If your spring is too light for your load you'll experience frame and slide damage - possibly even rail seperation - from the undue battering.

If your spring is too heavy for your load you'll experience short stroking and feeding problems.

Call the technical line at Brownell's and they'll give you the scoop on what you need for what you intend to do.

Light recoil springs are excellent for wad cutter type ammo (140-180 gr.) and hollow points as well. Makes it easier to load into the throated barrel when slide is chambering the bullet from the magazine at a slower cycle. A heavy spring will work pretty good with standard ball ammo (230 gr.), but if used with W/C or H/P ammo it may jam the bullet as it's being loaded. Don't use a heavy spring with light loads as you may experience the case not being able to be ejected, which means that it is unable to chamber another load. Not Good.