Spartan V 9mm mainspring #

[TheOtherLeft]

Hi all,

Does anyone know what is the Spartan V 9mm mainspring #?

I've heard it is 15lbs which is insanely light for a factory spring.

I want to lighten up the trigger pull and other than a DIY trigger job I wanted to lighten the mainspring but Wolff doesn't make a lighter mainspring.

Thanks.

[Hawkmoon]

15 pounds? Are you sure that's not the recoil spring? I doubt a 15-pound mainspring would even be reliable with most ammunition.

[Jim Watson]

I have heard but cannot confirm that.
If your DIY trigger job is correct, reducing the mainspring will have little or no effect on the trigger pull.
Tinker with sear spring tension. Even if you are not doing all the metal work for a very light pull, there are instructions on setting minimum sear spring at
http://www.brownells.com/.aspx/lid=1...b-Trigger-Pull

[Spyros]

STI is known for using some really, really light mainsprings, IIRC in the 17lb range. 15lbs doesn't sound right. Heck, finding such a spring for a 1911 might be tricky.

If you must, I hear Double Eagle mainsprings work, but you might get to learn a lot about which factory ammo has hard or soft primers this way.

[TheOtherLeft]

I installed a 15lb Wolff mainspring and a 8lb recoil spring. I also bought a 17lb mainspring just in case. The STI mainspring is definitely heavier then the 17lb mainspring.

The 15lb mainspring functions with my Federal primers.

[RickB]

My buddy's STI Edge does appear to have a 15# main. It won't reliably crack Russian primers. I'd bump it to at least 19#.
If you want to improve the trigger, work on the lockwork components.