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Main spring and trigger adjustments

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rich.tullo
Froneck
DA/SA
r_zerr
chiz1180
NukeMMC
javaduke
Texasref
bruce martindale
jjfitch
jglenn21
Tripscape
hengehold
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Main spring and trigger adjustments  Empty Main spring and trigger adjustments

Post by hengehold 1/12/2024, 5:08 pm

I recently built a 45cal 1911. Used EGW kit for hammer/sear/disconnect or. Initially I experienced some light strikes (~30% failure rate) increased the main spring incrementally to 19, 20, & 21 lbs springs. Trigger felt great with a 19# spring but had to increase spring weight up to 21# before light strikes have been eliminated. Now the trigger does not feel great anymore: feels much heavier and somewhat clunky compared to the lighter springs. Is there something I can do to offset this increase in trigger weight/sear engagement weight? 

Maybe adjust one of the fingers on the flat spring behind the grip safety to adjust sear & hammer engagement? 

-Trevor

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Post by Tripscape 1/12/2024, 5:27 pm

Simple answer is yes. Now do you want a scientific method or a quick method? Quick is adjust sear spring leaf to the point where it fails to produce a distinct click on the half and full cock and then increase it again slightly for a distinct click. Check for hammer fall via dropping slide on the empty chamber. Disconnector leaf can be adjusted not too light, but not heavy either. If you have pre-travel on your trigger it will only stage your finger better before you hit a sear wall if this spring is set heavy. If you vitrually eliminated pre-travel then the wall will be more pronounced if it is heavy, back off until there is still a fair amount of resistance.

Scientifically speaking You will need a trigger gauge. About 20-24 ounces on the disconnector leaf. About 11-16 ounces on the sear. All measured at the trigger as you add components. Friction with hammer will add 10-16 ounces for a 3.5lb pull.  Add as necessary wherever you feel.more comfortable if below 3.5lb. Mainspring has little to do with trigger pull weight on 1911.

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Post by hengehold 1/12/2024, 7:44 pm

Thanks for the info, I’ll give it a try. I would have agreed with the above quote before I personally felt the changes to the feel of my trigger.

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Post by jglenn21 1/12/2024, 8:40 pm

Curious you get light strikes with a 19lb mainspring. All I ever use in a 1911 and never have a light strike with any primer. Are you perhaps using a titanium firing pin?
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Post by hengehold 1/13/2024, 3:29 am

jglenn21 wrote:Curious you get light strikes with a 19lb mainspring. All I ever use in a 1911 and never have a light strike with any primer. Are you perhaps using a titanium firing pin?

I don’t believe I purchased a titanium pin but I can swap it out to be on the safe side. 

If a 19lb is supposed to be strong enough, what  else could be causing the light strikes?

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Post by Tripscape 1/13/2024, 4:44 am

Firing pin spring too strong? I am running a 16lb spring and it's igniting everything I throw at it. Reason I run it is that it's reliable with 22 conversion.

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Post by jglenn21 1/13/2024, 6:23 am

Cock the empty pistol then hold the hammer while you pull the trigger. Slowly let the hammer down.
 If you feel any resistance your sear nose is dragging on the hammer half safety. Loosen your trigger stop screw a half turn at a time, until you no longer feel the drag..
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Post by jjfitch 1/13/2024, 11:22 am

If you are not familiar with the process for setting up hammer, sear and main springs for lighter trigger pull weights, here is a tutorial:

"Brownell's: Weigand 2.5 trigger pull".

This will get you on the right path with the process and a list of tools! Smile


Last edited by jjfitch on 1/13/2024, 8:18 pm; edited 1 time in total
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Post by bruce martindale 1/13/2024, 4:36 pm

Excessive headspace? Firing pin energy absorbed by shoving the shell forward.

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Post by Texasref 1/14/2024, 8:33 am

A friend of mine had an STI 2011 that acted the same way. The fix was a longer firing pin. It might have been titanium also, just don't remember him saying anything about that. 
This might have taken up the distance if there was a head space issue.

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Post by javaduke 1/14/2024, 11:09 am

If I remember correctly, the standard mainspring rate for 1911 is 23 lbs, at least according to Wolff.  So it is definitely possible that 19 lbs causes light strikes, especially if a titanium firing pin is used (which is why I NEVER use titanium pins in my builds). 
Getting a decent trigger is a different story and generally speaking it does not involve any changes in the mainspring. Assuming you have brand new EGW components, and the sear face and hammer hooks are clean and don't require any stoning, you can tweak the middle and the left leaves of the three-leaf sear spring. The left one controls the sear and the middle one controls the trigger and disconnector. To achieve a 4 lbs trigger I usually start with the middle leaf and bend it outwards until I get close to the 2 lbs of the free trigger movement before it hits the wall. Then I bend the left leaf until the trigger breaks at 4 lbs or slightly over.  At this point if the trigger break is clean then no further adjustments are required. If I still feel any unwanted creep or roughness, I inspect and clean the sear and hammer surfaces with stones.

Hope this helps.

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Post by NukeMMC 1/14/2024, 12:18 pm

I replaced the Ti firing pin & spring in both of my SA Range Officer pistols with EGW when I put the EGW ignition parts in it. Never had any light strikes with the 19# mainspring. Jon Eulette did trigger jobs on both the 45 and the 38super.
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Post by Froneck 1/14/2024, 2:39 pm

Bending the flat spring for the sear and disconnector (Grip safety too) is not going to anything!
 The trigger pull changed because the heavier main spring increased the pressure applied to the sear and hammer hook! Lots of things can cause your problem and bending the flat spring will not help. You would be better off taking the gun to an expert that knows 1911 Bullseye triggers. Getting the trigger to work great is not as easy as some say it is! I like using light main springs in my gun so I can use a heavier recoil spring and never have a light hit problem. If your reloading Federal primers are easier to ignite.

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Post by hengehold 1/14/2024, 9:44 pm

Thanks for all the input so far.

The comment about excessive headspace is interesting. I suspect this is likely the issue. I have had mixed results that lead me to believe it can be headspace. The gun is a brand new build and have put a total of about 250 Rds through it. Below is the sequence of events as they have occurred. Notice some ammo does experience light strikes and some does not. Leading me to lean into the headspace direction instead of a firing pin problem. 

1. Gunsmith sent a 50yd test group, 15 shots sub 2” from ransom rest w/ FGMM. He did not experience any light strikes using #19 Main spring. 

2. I used factory Ammo, PMC 230 ball with 50% light strikes using # 19 lb main spring. 

3. Tested hand loads for function and groups from hand. ~100rds, no light strikes with #19 main spring.  Mixed brass. CCI LPP. 

4.  Verified final hand load recipe with different batch of brass. WCC Match Brass from 1980’s and ~ 7-10 reloads on them with same CCI primers as #3. Approximately 20% light strikes with #19 main spring. Increased up to 21# MS before light strikes disappeared. 

Does this point towards excessive head space?

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Post by Froneck 1/14/2024, 11:43 pm

CCi primers are hard. I also had a batch of CCI primers that were in a pistol primer box box that were rifle primers. Try Federal primers.

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Post by chiz1180 1/15/2024, 2:52 am

Are your primer hits centered or off center? You can check headspace with a headspace gauge.
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Post by r_zerr 1/15/2024, 7:46 am

Nobody has mentioned your firing pin fitting freely. You should have a noticeable protrusion beyond/rearward of the retaining block. Use a small allen wrench to push in on it and make certain that it will go way forward to produce lots of firing pin protrusion. It should return and protrude freely. I do not have my notes available but thinking .040"-.055" protrusion out the rear.
Since you identified a titanium firing pin, if you have a titanium hammer that is very skelotonized, that would be a next item to possibly replace. This assumes that everything else has been checked out, like not dragging the sear on your half-notch of the hammer.
You should be able to launch a wood pencil with the rubber eraser end against the breech. Several feet straight up is normal.

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Post by NukeMMC 1/15/2024, 8:26 am

You can measure the chamber with a dial caliper from the back of the hood to the edge of the chamber.  Should measure 0.898-0.920, preferably on the lower end.
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Post by hengehold 1/15/2024, 10:29 am

chiz1180 wrote:Are your primer hits centered or off center?  You can check headspace with a headspace gauge.
Primer hits are very much off-center. Is there a way to adjust this to make it more centered?


Last edited by hengehold on 1/15/2024, 10:47 am; edited 1 time in total

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Post by chiz1180 1/15/2024, 10:37 am

hengehold wrote:
chiz1180 wrote:Are your primer hits centered or off center?  You can check headspace with a headspace gauge.
Primer hits are off-center. Is there a way to adjust this to make it more centered?
It is part of barrel fit, though potentially could be a slide issue. Very common in older bullseye guns. The simple fix is to run federal primers, the better fix is to have the barrel fit correctly.
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Post by hengehold 1/15/2024, 11:05 am

chiz1180 wrote:
hengehold wrote:
chiz1180 wrote:Are your primer hits centered or off center?  You can check headspace with a headspace gauge.
Primer hits are off-center. Is there a way to adjust this to make it more centered?
It is part of barrel fit, though potentially could be a slide issue. Very common in older bullseye guns. The simple fix is to run federal primers, the better fix is to have the barrel fit correctly.

It is a Kart NM barrel fitted in a Caspian slide. 

Maybe it is a situation where lugs don’t have enough material removed/or too much material removed so barrel is sitting too high or too low in relation to the slide/firing pin?

I also have plenty of Rem LPP. How is hardness with REM primer compared to CCI & Fed?

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Post by chiz1180 1/15/2024, 11:09 am

Yes, that is the basic idea.
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Post by hengehold 1/15/2024, 11:11 am

chiz1180 wrote:Yes, that is the basic idea.

I have REM LPP also, any idea if those fit into the hard or soft category?

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Post by chiz1180 1/15/2024, 11:20 am

hengehold wrote:
chiz1180 wrote:Yes, that is the basic idea.

I have REM LPP also, any idea if those fit into the hard or soft category?
I don't have good data on them yet. Recently got some and have started testing, just been too cold for range time as of late.
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Post by hengehold 1/15/2024, 2:03 pm

chiz1180 wrote:Yes, that is the basic idea.

Is there a way to correct this off center fitting? 

It sounds like either way the barrel is scrap and new one will need to be fitted to have center primer strike.

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