Improving (or restoring) a 1903 Trigger

[RCS]

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

Information

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[ssgross]

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.

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.

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

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.