DA pull rate?

[Guest Bonedaddy]

:popcorn:Can the DA pull rate be changed and not affect the SA rate on a semi-auto? And approx. what would a job like that cost?

[Guest Jamie]

As for cost, I couldn't tell you, however, I can explain a bit about trigger pull weight. ( the force it takes to move the trigger from front to rear )

There are 4 things that have an effect on that:

1) the strength of the main spring... the one that powers the hammer or striker.

2) the trigger return spring... the spring that re-sets the trigger after it's pulled.

3) the roughness of the engaging surfaces of the parts that work together... hammer, sear, etc.

In other words, friction.

4) the geometry of the internal mechanism - some designs give better leverage between the trigger and the hammer than others.

All of those things have to balance out. Too little force on a particular spring will cause everything from a trigger that doesn't return to reset after it's pulled to light primer strikes.

So, due to all of the above, there's no way to significantly lighten the DA pull without having some effect on the SA pull.

The good news is that the sear engagement could be altered to keep the SA pull around a particular weight if it were found to be too light. But that would require welding something up and re-cutting it, or new parts, possibly, and would probably be more complicated or expensive than it would be worth, depending on the gun.

Oh, and I should also mention that on semi-autos with hammers, changing the mainspring can have an effect on cycling reliability, since the slide having to re-cock the hammer is part of the whole equation with the recoil spring. If the mainspring is too light, the recoil spring may need to be a bit heavier to keep the slide from cycling too fast when the gun is fired.

I know that's probably not the answer you were looking for, but I hope it helps some.

J.

Edited April 23, 2010 by Jamie