S&W 745 - is it possible to INCREASE trigger pull weight?

[javaduke]

I know it's rather unusual, but I need to increase the trigger pull weight on my 745 just a hair. It does lift 3lbs weight but doesn't lift 3.5lbs. I was hoping to find a heavier trigger return spring at Wolff but they only list reduced power springs. Wondering if you guys know any tricks or have any good ideas.

Many thanks!

 

[BC38]

Is that the "drawbar plunger spring" in this exploded diagram at Numrich?
Smith & Wesson Model 745 Parts | Gun Parts Corp.
If so they seem to have the standard factory ones for under $3

 

[javaduke]

Yes but that's the thing, what I have is a standard rate spring and apparently it's too light and allows the trigger to break below 3.5 lbs.

 

[BC38]

OK, I assumed you weren't the first owner and someone had swapped it out.
Maybe you could pre-load it a little with a shim between it and the plunger? Just a thought.

 

[Sevens]

Pretty sure that if you bent the sear spring a bit, you could add the weight you seek.

 

[BMCM]

How old is the mainspring? A fresh factory mainspring #103620000, might add a bit or you can increase the spring weight rating there with a Wolff xp spring and add some more.

Also the light trigger can be a sign of excessive wear on the sear and or hammer's full cock notch. Ever had the pistol double?

Cheers
Bill

 

[donk52]

Changing trigger pull weight is a tricky thing with the early semi autos.
It was only done on the Mod 41's and 52's. Changing springs will not fully remedy the cause of light or heavy trigger pull. These guns were "assembled". We never checked trigger weight. The key areas are the hammer and sear surfaces. Bending the sear spring could help some. The hammer sear connection on 745, 645 and the 9mm's is similar to the 52. We had a special fixture to put the sear in and was stoned, finishing with an arkansas stone to finalize the trigger pull. The 41's and 52"s were to pick up 2lbs. and fire at 2.5 lbs. Other than bending the sear spring a little,I would suggest leaving it alone. If you mess up the sear or hammer you would probably be right back to where you were having to buy replacements.

 

[javaduke]

Thanks, folks, the gun is almost brand new, so I believe all the springs are at their original factory rates. I'll try and bend the sear spring and see if it does the trick.
The gun shoots really well, I removed the rear sight and machined a custom piece of rail so that I can mound a small red dot, I zeroed it at 50 yards and shot two X and two 10s in a row with my loads! The only thing I need now is to make it 3.5lbs legal for Bullseye.

 

[Sevens]

I would be extremely interested to hear how this tale plays out. Not the trigger pull weight so much... but the accuracy. I've never heard of anyone squeezing 50-yard accuracy that would allow them to truly compete in Bullseye.

I love both my 745's but they haven't distinguished themselves on that level. The 845 and 945's that I own run circles around both of them on paper.

 

[javaduke]

I was surprised by how accurate is it, I haven't tested it on Ransom Rest because I don't have the inserts, but all my shots were perfectly on call, so I estimate the Ransom rest group would be around 2" - 2.5" which is plenty for me. My load is classic 200gr lead SWC over 3.7gr BE.
That being said, I wish it was possible to install a Briley bushing or something similar to what 845 and 952 have.

 

[malph]

I would be extremely interested to hear how this tale plays out. Not the trigger pull weight so much... but the accuracy. I've never heard of anyone squeezing 50-yard accuracy that would allow them to truly compete in Bullseye.

I love both my 745's but they haven't distinguished themselves on that level. The 845 and 945's that I own run circles around both of them on paper.

I've seen the same. Nice guns. Great triggers but...not the same level of accuracy as 845s and 952s.