Back yard gunsmithing.

ShadeTree

Handloader
Mar 6, 2017
3,515
3,019
With an emphasis on back yard. I'm not a smith and don't pretend to be, but I have a born with pension for tinkering with, learning about, and working on anything I feel I can make better, and in the case of guns also confirming several different ways that it's safe.

Everybody is different, so if the mechanics of guns interests you, you might find what I worked on interesting, if not no offense taken. :grin:

The 03 Sporter I recently bought has a trigger that was obviously worked on and is very smooth and light. Breaks at 2 lbs when I tested it on a trigger scale. But it also has the longest trigger pull by far of any gun I've ever run across. Smooth and light or not, the extremely long pull was an impediment to accurately rating group sizes when shooting it on the bench the little bit I shot it so far.

The Springfield trigger is straight mechanics with no adjustments, but is remarkably simple and reliable in design. Top of the trigger has a curved cam that sits against the bottom of the receiver and gives you lots of leverage. Trigger is pinned rear of center through the sear, sear is pinned forwards of center through the receiver. Pull the trigger and the cam going against the bottom of the receiver pivots the sear down in the rear until it clears the hammer, while simultaneously pivoting the sear up in the front, compressing the spring giving you your trigger pull and return tension.

Trigger with cam at top.



Next picture is trigger and sear. The well in front of the sear pin hole is where the spring goes from the sear to the bottom of receiver. As you can see pull the trigger and that cam pushes up against the receiver forcing the sear down in the rear, up in the front compressing the spring.



So what to do about all the travel? My idea was to try and shorten the distance the trigger could return to. I decided to try and shim the area on the sear that serves as the return resting place for the trigger. If you look at the picture above, you can see the ear at the front of the trigger that rests on a flat spot on the sear.

I had a small piece of .015 thick, metal shim stock. It ended up I needed 2 of them for a total of .030. That doesn't sound like much at all, but keep in mind the end of the trigger is a long ways off from that ear. .030 under the ear translated into more than 4 times that distance at the other end based on before and after measurements.

The next picture is the 2 tiny pieces of shim I cut. The first piece I took a small file and notched the piece out to fit the shape of the sear it was placed on. The second piece I just cut in a thin straight line to fit at rear of the first piece.



I then reassembled the trigger and after cleaning any and all oil off of the sear face the pieces were going on, and the pieces themselves, I took a pointed tooth pick and best as I could smeared JB weld on both pieces. Put the notched out piece on first, then the second piece on top of that.

With the trigger assembled and pieces in place, the trigger now had spring tension on it pushing down on the shim pieces overnight while the JB weld cured.



Tested it slamming the safe off, slamming the bolt shut, and butting the rifle on the floor and it holds without firing. I now have a springfield trigger that breaks against a wall without creep at 2 lbs. Lighter actually than what I like for hunting but the only way to change it is go to a heavier spring.

Trigger works like a champ but it remains to be seen if the thin JB weld will hold with the percussion of firing. If it doesn't I will try a single piece of shim .030 thick and cut it to run up along the side edges of the sear along with the flat area, so it has much more surface area to grip.
 
It works. Not a trigger tuner but JB weld? Just don't know. Looks like thoughtful and careful work.
 
ethmoid1999":rzu7ifz8 said:
It works. Not a trigger tuner but JB weld? Just don't know. Looks like thoughtful and careful work.

Yes but not weld involving a safety issue. Worst that can happen is if the weld doesn't hold the shim will fall down and it will go back to a long trigger pull.

JB weld is an old product but good stuff. It has a tensile strength of just under 2 ton and a flex strength of almost 4 ton. Once it cures it's extremely hard and is completely resistant to water, gasoline, and about any other petrolium or chemical you can think of. The issue might be adhesion. It has an adhesion strength of 1800 lbs but in this case it's extremely thin.
 
Still didn't get around to shooting this gun with the improved trigger, but after thinking about it I decided the weak link in the whole deal was the second shim. I took the trigger out and apart and knocked the top shim off, and in doing so confirmed that the bottom shim is not going anywhere. I then put a heavy bead of JB on top of the remaining shim and after 24 hrs when it was good and hard, I filed it flat and level taking a little bit off at a time and checking it until I had it down to the right thickness. That heavier layer of JB wont go anywhere and farther cemented on the remaining shim. Still breaks at 2 lbs.

The action has some front to rear wobble to it when down in the stock, it really ought to be bedded so I guess I'll do that next. Bedding an action is my least favorite thing to do with guns. Pain in the rear. I'd sooner trim brass. :mrgreen:
 
JB weld is amazing stuff, I've used it to repair boats, outboard motors, and the floats on planes(temporary and emergency repairs) never thought about using it on a trigger. Creative work to be sure. A classic Alaska fix for sure.


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salmonchaser":3c756wq1 said:
JB weld is amazing stuff, I've used it to repair boats, outboard motors, and the floats on planes(temporary and emergency repairs) never thought about using it on a trigger. Creative work to be sure. A classic Alaska fix for sure.


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My experience with JB is that it tells you pretty quick if it's going to accomplish what your trying to do with it. If it's not going to hold you know it, if it does it will be there until you grind, file, or knock it off with a chisel.

A real trigger job on a factory non adjustable trigger would take hours and evenings of meticulous stoning to lower the sear height or overbite if you will, down to where it is doing what this trigger is now. Mine is not a real trigger job I will admit that, but it's a simple mechanical fix that accomplishes the same thing. If that JB holds which I expect it will, I will wear out 2 barrels and that trigger will still be breaking how it is now.
 
ethmoid1999":2mzmh9lq said:
Keep us updated. You do far more than I ever attempt.

That's probably not always a good thing on my end, someday it might get me in trouble, but I try best I can to think things out ahead of time so I don't ruin something or do something unsafe.

This is the first bedding job I did a couple years back. Was I scared I was gonna screw up? Yes! Nobody around to walk me through it. I used some wood putty I had that I put some mineral oil in until it was playdough like in consistency so I could plug up any and all holes I didn't want bedding material getting into. Put a single layer of tape on the front, sides, and bottom of the recoil lug. Took wood down in the stock with a small grinder on a dremel where I wanted the bedding to sit. Once you start hogging out wood there's no turning back.



Here it is action in the bedding, action screws lightly ran in, and tape ran around the action and stock to hold it in place until it sat up overnight. I don't remember what I used as a release agent, something here at the house, but whatever it was it worked, I was sweating bullets until I got it apart! Ha.



It didn't turn out bad, and did what I intended it to do as far as helping tighten up the gun and make it more consistent. This was on a model 7.



 
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