stupid question regarding Stinger recoil spring

[Colt45guy]

Since it's payday, I thought I'd stock up on a few spare parts for my Stinger. I contacted LB for the proper weight recoil spring--was told #21, commander lenght. I couldn't find any locally, so I put in an order for some Wolff.

What the heck is a variable spring, and what is your general opinion of 'em?

Thanks!

Colt

[SAWBONES]

Wolff's variable weight springs exert disproportionately more force the more they're compressed, and less when less compressed, instead of giving similar resistance throughout the entire compression length.

The theory is that they provide enough slide dampening during recoil even at high force levels (which result in greater degrees of spring compression) yet won't batter the frame or slide when the slide returns to battery (since then the spring is under less compression).

By all reports they work well, but I lack personal experience with that spring type.
I've had dozens of good springs from Wolff, for different guns, including various 1911s, but they've all been of the "regular" sort, whether recoil, firing pin, mainspring or leaf types.

[SAWBONES]

BTW, my Baer Stinger runs fine with a 20# standard ISMI recoil spring.

[Black_Talon]

FWIW, I've been using Wollf 20# Commander springs in my Stinger. They work just fine with factory JHP loads like Ranger T and Speer Gold Dot and it seems like regular 18# springs would work well too. It's on my "to do" list one of these days.