[marklbucla]

I know the standard mainspring weight for a .45ACP is 23#, but does that apply to 9mm variants as well?

[schmeky]

MarkB,

If you mean the hammer spring, then yes, it is 23# on the 9mm version.

I run 17# mainsprings in all my 1911's, including my converted Colt 38 Super to 9mm.

[TexasRifleman]

f you mean the hammer spring, then yes, it is 23# on the 9mm version.

I run 17# mainsprings in all my 1911's, including my converted Colt 38 Super to 9mm.

The hammer spring IS the mainspring on a 1911.

The spring under the barrel is the "recoil spring".

23lb is good for pretty much every caliber unless you're having problems.

[SureThing]

What is a good weight to lower the trigger lbs, but still have good primer strikes?

[MICHAEL T]

What is a good weight to lower the trigger lbs, but still have good primer strikes?

A lighter spring won't really change the trigger that much. What it will do is allow the slide to come back faster . Remember slide cocks hammer . This slows slide and all spring work together.. A trigger job and adjusting the sear spring (spring under gripsafety) will lightned the pull. 4lbs for carry min.
Leave the main spring alone.