Well.... The proper way is to tune the sear spring after all of the other prep is complete. That will get you more reduction than changing the mainspring and have no effect on the other functions of the gun. The mainspring is an integral part of the cycle of operation (recoil). Changing it has the same effect as reducing the recoil spring weight, at least for the first part of the cycle.

 

Hope this helps, along with post #2,

At your browser type: "Jack Weigand 2.5 pound trigger pull" this will take you to the Brownell's "How to" stuff.

You'll add weight to each sear spring leg to get your desired trigger pull weight.

Cheers,

 

And to answer your question, just changing mainsprings alone is good for about 1/4 to 1/2 lb. Usually closer to 1/4 lb.

 

I wouldn't drop the mainspring weight, because that requires balancing the recoil spring with a heavier one. Not beneficial for the pistol! Like the others have said, you need to tune the sear spring.

 

Not necessarily. 23 lbs is serious overkill for what is required for reliable ignition. You can easily compensate for any change in the mainspring, with a different (ie. less radius) profiled firing pin stop - if even that is required.

But as you said, a heavier recoil spring may be required to compensate. All depends on what ammo is being used.

 

He should be running a flat bottom FPS in a Commander anyway.

But tune the sear spring.

 

He should be running a flat bottom FPS in a Commander anyway.

And why is this? I've never had a reason to with almost a dozen Commanders I own. I typically run a 20 lb recoil spring, however. There are no "shoulds" - just what's right for one's own gun and choice of ammo.

Remember that factory standard weight recoil spring is 18 lb. for Commanders to compensate for the lighter slide mass, and shorter travel. A flat bottom firing pin stop is not necessary, unless you are fine tuning for your choice of ammo.

 

Thanks "shane45-1911", for your answer to my original question. So, about a 1/4 to 1/2 lb. reduction in trigger pull weight. And yes I know about balancing the recoil spring when mainsprings are changed. Also, I know that the final fine tuning for trigger pull weight should be done with the sear spring. All I wanted to know was how much of a reduction in trigger pull weight would result in changing just the main spring. Now I know. Thanks everyone for all the replies.

 

A commander slide is shorter and therefore has less mass then a GM slide.
This leads to higher slide velocity which is initially slowed by the FPS cocking the hammer against the resistance of the main spring.
A flat bottom FPS decreases the leverage the slide has against the force of the main spring.
This allows the mainspring, via the hammer, to slow the slide more than a FPS with large radius.

 

Yes azlou - re-read my post. I know all about Commanders.

As I said, the statement that he "should" be using a flat bottom FPS is incorrect.

 

Your knowledge of Commanders , as stated by you, doesn't include using flat bottom FPS.
I was simply explaining the theory behind the flat bottom FPS.
What he should or shouldn't do is above my pay grade.

 

What he should or shouldn't do is above my pay grade.

LOL. True enough. I just don't like hearing the word "should" when it comes to some things.

 

Back to the OP, I wouldn't run less then a 23lb main spring in my Commander.

 

Springs in a 1911

The mainspring doesn't have a great effect on the hammer pull, and changing the mainspring to reduce the trigger pull 1/4lb. doesn't seem all that beneficial.

I set up my springs in a 1911 strictly for the power of the ammo used and the way the sight tracks under recoil. With a stout .45acp load in a 5" GM, I may use a 23# mainspring and a 16# recoil spring. For a midrange .45acp load I may use a 19# mainspring with a 13 or 14 # recoil spring. For my 1911 9mm GM set up for IDPA, I use an 18# mainspring with an 11 pound recoil spring for a load with a 135 Power Factor.

Every gun may be different in the way it unlocks, how smooth the slide works on the rails, how tight the slide stop pin leverages against the barrel feet, etc. There is no magic answer for any load for any given gun, so it just takes time and a trial and error process to determine the best spring set up for the shooter's preference using a particular load for that particular pistol.

 

Every gun may be different in the way it unlocks, how smooth the slide works on the rails, how tight the slide stop pin leverages against the barrel feet, etc.
There is no magic answer for any load, so it just takes time and a trial and error process to determine the best spring set up for the shooter's preference.

Perfect. You saved me a bunch o' typin'.

 

In plain English, what is a flat bottom "FPS" ??? What does FPS stand for ? Thanks.

 

In plain English, what is a flat bottom "FPS" ??? What does FPS stand for ? Thanks.

FPS stands for firing pin stop.
I believe John Browning's original plans called for a flat bottom FPS with a squared bottom (less radius) profile, as compared to the more gradual radius FPS that came later at the Army's request.
Respects, Pedro.