Original Design Q. - Sear Spring Weight

original: forum.m1911.org
Retrieved: December 01, 2011
Last Post: December 11, 2009

Lazarus
10th December 2009

Original Design Q. - Sear Spring Weight

I was looking over the old threads on the topic of sear springs. Most posts were asking how much sear spring pressure gives a certain trigger pull? That incorrect understanding must be the result of countless internet articles on how to do a 2 pound trigger pull, etc.

Focusing on the true purpose of the sear spring (the left leaf of same) - which is to insure that the hammer is cocked during recoil and remains cocked during a slide drop - is there any mention of a recommended safe sear spring weight in the original design? The dimensional drawing of the spring gives a basic idea of what was intended. But what is a safe spring weight for an unmodified Government pistol?


Hammerdown
10th December 2009

That article you're referring to was written by Jack Weigand, and he uses a Colt sear spring and tweaks the bend on the middle and left legs until they exert equal pressure (measured with a trigger pull gauge). He uses 8 oz. for each when trying to obtain a 2.5 lb. trigger pull.

I suppose you could take a stock, new Colt spring, and measure the trigger pull weight necessary to first get the disconnector leg to move. Then measure the pull weight necessary to get the sear spring leg to move. Subtract the first reading from the second to get the weight on the sear leg.


egumpher
10th December 2009

Other than for the 2-lb-trigger target crowd out there is there any reason that 10-12-14 oz. wont work for the rest of us?


Hawkmoon
10th December 2009

Typically, about one pound (16 ounces) for each results in about a 4- to 5- pound trigger (depending on how well other parts are fitted and tuned).


Dave Berryhill
10th December 2009

The ordnance prints only specify the material, heat treat and shape of the sear spring. I'm guessing that there was a range that the trigger pull weight on a GI pistol had to test at before it left the factory but I've never seen anything. There are probably some "go" and "no go" weight ranges in some of the old ordnance manuals for repairing or rebuilding the pistols.


Lazarus
11th December 2009

I figured a stock spring might be about a pound. I have never relied on reduced sear/trigger spring weight to adjust the trigger pull, although I am fully aware that it is commonly done that way.


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