The Unofficial P64 Resource Forum

Purchased another Model P64 (my third) in great condition but,missing the trigger spring. As usual, I replaced the springs with new Wolff and was able to acquire a new trigger spring. Took it to the range the other day and got quite a surprise. On DA the trigger pull is what I what I expected with the new 18 lb hammer spring but, after the first shot the trigger pull had to go down to around ONE POUND with the result of some quick and surprising shots.
My question: Is it the hammer spring or the trigger spring? And, how can I make the needed adjustments?

Gotta be the hammer spring.

The trigger spring just makes the trigger go forward when you release your finger. It does very little to affect the trigger pull.

Using a lighter hammer spring will reduce the ungodly double action trigger pull (I am guessing that's what you are calling your first shot). However, among other things, this also affects the trigger pull in single action (after the first shot as you mentioned). It's not unusual to have people change the hammer spring and report that single action trigger pull gets really light. If it is too light, the only thing to do is go up a pound or so on the hammer spring.

Oh, another thing. Check that little ring (part 11a, strut washer from the parts list) that goes against the end of the hammer spring. If it gets left off, that could screw up the spring pressure.

+1 daytonaknight

thanks a lot. Let me check the springs as you suggest.

Do you mean that this one has a lighter single-action trigger pull than you other P-64's?
It so, are the others stock or modified with lighter hammer springs?

Apparently with this P64 I used an 18lb replacement spring. When I checked, as suggested by some members here, I found that I had installed 19lb springs on my other pieces. Believe me, I made a difference. Since I first posted I have changed the spring to 19lb and test fired at my local range. Still light (as are the others) but not scary anymore.

The spring that primarily affects the SA pull is the sear spring - that one is hard to replace though! The trigger return spring does have an effect on SA pull. I was able to increase my SA pull from 3# to 6.5# by changing the trigger return spring to one of my own manufacture using stiffer piano wire. Works like a champ! The hammer spring primarily affects DA pull.

I have the 19lb spring on mine for the reasons you mentioned. I agree any lighter would be too light.

I did the 18lb hammer spring exchange a few weeks ago.

Yesterday, a local gun smith with a digital gauge checked the SA and SA trigger pull on my (1973) P-64:

Single action pull was a consistent 3.4lbs.

Double action pull was 12lbs.

Of course, with your P64, YMMV.