Improving (or restoring) a 1903 Trigger

So I've been working on restoring a badly abused 1903a3 sporter. I did a lengthy post step by step on fitting the new Minelli stock. Well, I had a new minty trigger to put on it, and after much reading decided to learn more about the 1903 fire control by tinkering with the old one. It went so successfully, I think I might not be needing that new one after all. In addition to plenty of deep rust and pitting all over the shoe and trigger guard, here is what I was up against...
https://www.milsurps.com/attachment....2&d=1617326981
A weld had been been tacked on to the front stop of the trigger to build up material. In affect, this causes the trigger to be permanently held after the first stage. As it was, it had only the 2nd stage, and pulled a gritty and creepy 4.5 lbs or so. I'll post pictures along with what I learned and how I figured it all out, main references being TM 9-1270, and Clark Campbell's summary thereof in his book The '03 Springfield. It's noteworthy to mention that both of these sources, as well as all the internet experts, will advise to swap parts around until you get a combination that works. Since most of us don't have buckets of cocking pieces and sears laying around, and spare parts will inevitably be more expensive and hard to find in the coming decades, I thought I might learn how to do it using what I had, and pass it along.

Sometimes you could see a see a trigger guard that has been punched in the front of the slot to keep the trigger from returning all the way froward. Or a shim soldered on the trigger shank and even a pin drilled and installed to keep the trigger rearwards bit.
Ive managed to wind up with two of the bottom metal pieces-trigger guards that have the pin drilled transversely to keep the trigger from moving forward,allowing the rifle to be fired. They'll work both ways.
I never seen one welded up roughly like that one though. I bet if you could see the trigger guard that was with it, it would have had the punch-chisel mark in it to suit the user.
Gently rounding over the sharp edge of the sear when your done seems to help, at least for me when I fiddle with that sort of thing.

I have a low number SA Model 1903 that was converted to 22 rim fire with a barrel liner silver soldered into the bore and uses the M2 bolt.

The sear spring has a least one coil removed and works out fine with an excellent trigger pull - but I do not think it would be a good idea on
a center fire rifle

Quote:

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Originally Posted by Doco overboard

Sometimes you could see a see a trigger guard that has been punched in the front of the slot to keep the trigger from returning all the way froward. Or a shim soldered on the trigger shank and even a pin drilled and installed to keep the trigger rearwards bit.

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Thanks, Doco. I have the milled trigger guard it came with and so just took a look. There are no alterations or tool marks on it. By the way, thanks also for your stock fitting post. When I did my first stock, I found it very useful.

After many hours with layout fluid, checking contact surfaces, comparison against a NOS trigger and cocking piece set, and my TM & Campbell references, I think I have figured out how and where the the trigger was altered. This may be a good starting point in describing how I brought it back to normal and safe function. First, I'll use illustration No. 53 from pg 220 of Campbell's book for common nomenclature.
Attachment 117091
On this trigger, the forward trigger stop, or notch (unlabeled above) had material welded on trigger notch, then filed flat there to push the trigger permanently through first stage. The sear engagement with the cocking piece was then increased by stoning down the bearing hump, giving enough engagement for safety, and a smooth creep until breaking at what was likely 4.5-5lbs originally. It originally tested at 5lbs, and dropped to 4.5 after cleaning and lightly polishing the contact surfaces.

Quote:

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Originally Posted by RCS

The sear spring has a least one coil removed and works out fine with an excellent trigger pull - but I do not think it would be a good idea on
a center fire rifle

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I tampered with the old sear spring as an experiment. After what I learned, I do NOT recommend altering it unless the first stage pull (after polishing) is > 3 lbs. In fact, there is no mention in the TM of altering the sear spring. If the first stage is > 3 lbs after polishing, I would even recommend spraying the top of the "bearing" hump and bottom of the receiver contact area with dry lube, and only alter the spring as a last resort. I'll skip ahead to the punchline on the dry lube...after I had the trigger breaking how I liked it, and began experimenting with the return spring, the return function felt sticky - that is when pressing through the first stage and then letting off, the return to full engagement wasn't smooth anymore. So I cleaned all the surfaces, which still had traces of layout fluid on it, and hit them with Hoppe's dry lube. This dropped my 4 lb trigger just under 2 pounds, with a half pound first stage! What I learned is that the contact surfaces still have some original tool marks on them, and my dry lube was like glazing a cast iron skillet. I cleaned it off with acetone, and finished with a drop of oil. This gave me the final 3.5-3.75 total pull, with 2lb first stage.

Next post...getting the first stage back, and smoothing out the pull.

Here is a permanent link to TM 9-1270
https://ia801209.us.archive.org/14/i...44TM9-1270.pdf
which is keyword searchable.
Using a micrometer, I checked some measurements of my NOS trigger against Campbell's "Full Size" diagram above. His figure is very close to actual, +/- the width of the lines. These gave me a reference for removing material on the welded portion.

There was relatively a lot of material to remove from inside the notch, and of course the slop on it's nose seen in the picture above. To get close to where I needed to be, I first used a disk of 60 grit on a dremmel. Almost all but the last bit of slop weld was removed from the front first, and then I used a Norton medium grit triangular stone to get a nice square front, with no more weld. I then did the same with the flat of the notch
Attachment 117092Attachment 117093Attachment 117094
I should mention that I cleaned all the corrosion from the trigger. Only the bottom, exposed, part of the show was badly rusted. I ground it off with dremmel sanding drum, then smoothed and rounded all out with these abrasive bobs. They are available in a variety of grits, and are really great for preserving rounded edges. I used 60 grit drum to get past all the pitting, then 120 grit bob, 240,320,600, and 800, on all exposed parts of the trigger. I used only a 320 bob on the upper part of the trigger, enough to remove the original finish. I left the top contact surfaces untouched for this stage, and finished the front portion of the shoe with jeweler's rouge to achieve a mirror polish.

On test fitting after fixing the front notch, I had a 5lb total trigger, with a very short-stroke 3lb first stage. This is where, after comparing against my new trigger, I figured out the bearing hump must have been stoned. This would increase sear engagement, and bring the heel in contact with the receiver sooner. This increased engagement could be noticed in the very long travel of the 2nd stage before an awkward, gritty final break.

Next post, squaring off the jagged contact surfaces to produce a clean break, and polishing the contact surfaces on top of the trigger, and under the receiver. This gives us a blank canvas to work with. At this point, if I have 3-6lbs total pull, with a smooth, no longer abrupt first stage, I would consider the trigger "restored". We can then adjust the engagement if needed, and the "balance" regarding the start position of the 2nd stage in the stroke, and of course remove any trace of creep in the 2nd stage.

Go to Century Arms, Intl. Go to Surplus Parts. They have new (NOS) sears, and near-new Grooved Triggers. Piles of near-new 03 and M1917 parts. Good luck.

First up, coat the contact areas with a sharpie or layout fluid (sharpie requires more work to wear off than layout fluid die). You want to mark the underside of the receiver, top of the trigger, face of the sear nose, and sear notch on the cocking piece. Here is what I found...
Attachment 117169Attachment 117170Attachment 117171Attachment 117172
The diagram shows ~1/8 inch engagement of the sear nose with the sear notch when in battery at rest. Looks like I have right about that, but it doesn't bear even, and the edges of sear nose and sear notch have some nicks or burrs. To get a better idea of how much engagement I'll have after evening out the faces, flip upside down and you can see where the sear engages and, using a sharp pencil or sharpie, mark the exposed part. Looks like I have more engagement than the layout fluid showed.
Attachment 117173Attachment 117174

Next, I used my stone to square off the edges of the sear nose and sear notch. The top of the sear nose is squared off thus, using the pin recess loop as a guide.
Attachment 117175
Use plenty of thin oil on your stone. go very slow to keep short, even and square strokes. Reassemble and check for even engagement (ignore doing anything about the feel for now). The goal here is to just knock down the high spots and burrs, we are not adjusting how deep the engagement is at this point. Clean the surfaces when you are done. Next, lightly stone any burrs off the top of the trigger, and polish the humps and the receiver bottom. The trigger tops are generally pretty smooth (I've never seen one that wasn't anyway)...a little rouge on a cloth dremmel bob works good. The parkerizing under the receiver is a bit rougher. Those little soft abrasive wheels I showed a picture of can be trimmed to the perfect width for the receiver by holding a razor blade to it while it spins. I knocked the park back with a gently touch of the 400 grit bob, followed by the 800 grit bob, and finally some rouge on the cloth wheel. There are likely tool marks in there, but we aren't removing them, just polishing will smooth their edges in the direction of the trigger's travel. I also very lightly polished the park on the inner side of the "ears" to remove any grit in the rotation of the sear. If I had a stone small enough to fit in the channel, I would have used a stone like the other contact areas. If you use a dremmel...use the slowest speed to control your work. Even the finest bob polishes quickly. Mine had already been lightly polished at some point, so this was very easy and fast.
Attachment 117177

Now we lubricate and reassemble, and dry fire a few hundred times. Eyes closed, front rest on the kitchen table, imagining a target but focused on feeling the trigger. You will likely have plenty of creep like I did, and you may not like the balance between first and second stage, or the weights of either. Make notes of what you have and what you want. If you did your job in the step above, even with awful creep it should feel like pulling a hot knife through butter. What to make note of to work on in the next step.
1) Is the trigger loose at rest? the front notch (the part with the weld on mine) may be too small, or the return spring may be weak cut too short, or broken.
2) Is the first stage well defined?
3) Make note of the balance of travel between the first stage, and the creep in the 2nd stage, e.g. mine was like 30% 1st, 70% second.

Next post, we will dive into how the different surfaces control each part of the pull, and adjust as needed or desired. Per the manual, total weight of 3-6 lbs with a well defined, longer 1st stage, and sufficient sear engagement in battery at rest is serviceable. You need minimum of 3.5lbs for the "games". We have some work to do on this one.