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I've lightened the trigger and bolt


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I'm no gunsmith, despite running sporterizing.com, but I had some luck with my 1927 A1, not perfect, but yes, progress! Here is a picture of the nasty, rough trigger assembly from the factory, before smoothing it up. Remember when reassembling that the silver piece on the very bottom of the picture of the trigger assembly has a point that goes under, not over the silver part in front of it. It helps to have past dental lab experience. Dremels are almost like what we used to work on crowns and bridges. I used a cutoff wheel and removed about a twist and a half of the firing pin spring. Then, with great trepidation, I worked on the trigger assembly. Pull down the little c-shaped spring arm, then remove the assembly. Lots of pictures saved the day. It took a lot of time, but here's what I did: rubber wheel surfaces smooth. Rubber wheels are good to have in your Dremel kit. Rubber points are nice to have too. You use a stone and shave the points into whatever shape you want. I lightly used the rubber wheel, 320 grit, and 400 grit sandpaper. I also used router bit diamond files (fine and extra-fine). I didn't remove a lot, but smoothed up stuff. I don't know the names of the various trigger assembly parts, but the front-most spring, which the trigger has to fight, got a twist removed with a silicon carbide Dremel wheel. I also removed one tiny twist of the smallest diameter spring in the trigger assembly. Smoothed up the sear and the firing pin catch. I wish I knew the part names, but smoothed the contacting surfaces. I also used my pinky finger on pieces of the 320 and 400 grit sandpaper on the feed ramp. It's too hard to fit the rubber point in there. It's not perfect, but better. I also used the 320/400 grit sandpaper on the bolt. I also removed a twist and half or so of the firing pin spring.

 

It was tough to reassemble, but you look on the side, and keep aligning the holes with a punch. The good thing is the front pin of the two engages before the rear, so you just get those front parts aligned and dropped in, then get the rear ones engaged, one part at a time. The trigger is lighter than it was, and cocking it is sure better. The Sarco drum is still vexing me with locking open after every one or two shots. I have no idea what is holding it open? I fitted one of four 30 round magazines I bought, and it works nicely! Use the Dremel aluminum oxide cylinder for raising the magazine hole.

 

I didn't like the flat stock finish, especially with such nice crotch walnut. Minwax Wipe-on Poly looks pretty good. I cut the buttstock shorter, but now the buttplate is too small. I'll try welding 1/4 square iron around the buttplate, then grind it back and polish it.

 

I'm sure somebody won't be happy with my methods, but I can tell you it's a far more pleasant shooting experience than a week ago!

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Edited by ltcajh
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The Sarco drum is still vexing me with locking open after every one or two shots.

 

The bolt hold open is tripping for some reason, did you misplace one of the springs when you had all of that disassembled? There should be tension on it until lifted by the stick mag tab on "empty", never by a drum magazine.

 

This topic should be posted in the Semi-Auto forum, perhaps Dave will move it over there when he catches up.

 

Welcome to the board, posting and reading will bring in more expert voices, that's how we learn and share the hobby.

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As for working on the 27A1 in general, while it's not cheap, I've found the AGI Thompson video pretty useful for working on my 27A1. The only real criticisms I have (at least with the version I have) are that the semi auto 27A1 info is intermingled with the full auto presentations; and, somewhat related, when Mr. Bush starts to disassemble the 27A1 he does not re-caution the viewer to make sure that the safety is in the "FIRE" position before attempting to slide the trigger frame off the receiver. The Owners Manual, of course, has the caution. The version of the video I have (2005) could be obsolete and there may be a newer version.

 

I do not have any affiliation with AGI.

 

MHO, YMMV, etc.

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The furniture looks awesome. Did you do any sanding first or just wipe on the new finish and buff it out?

 

FWIW, I was out shooting with my recently new 1927a1 and a 100 round drum from Auto Ordnance and every 20-50 shots the bolt locks back. I didn't have a 3rd hand or anything in place that would be bumping the bolt catch.

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Thanks all. The drum was acting up before working the trigger group. Yeah, the bolt is way free and clear well behind the drum. I dont know if maybe the cartridge presentation isnt high enough? The drum is the only magazine acting up this bad. The 3rd hand was not inserted.

I did some fine sanding on the stock. I think theres 3 or 4 coats of finish. It helps when you wipe on the finish to place the handle over a nail, up through a piece of wood, so your part can dry without screwing up the finish. I'm 5'7" tall, so that stock is too long. I marked a tracing with a compass with a pencil lead, wrapped some masking tape in front of the pencil mark (made all the way around the buttstock), then cut it on the bandsaw. A little sanding on the oscillating spindle sander, then you get to see the buttplate is now too small!

I only paid $800 at the PX for this, and no tax!

Edited by ltcajh
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I looked up the parts I worked on.

1. Remove pivot plate with a gentle levering action from a medium-bladed standard screwdriver. Gently tap with pins on the opposite side with a punch when you've cleared the spring from the safety switch pin.

 

2. Shortened the pawl spring, firing pin spring, and lifter spring a coil and a half or so. (Don't do this modification!)

 

3. Polished the sear block, firing pin connection interface with sear block, pawl, and trip lever.

Edited by ltcajh
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Since I couldnt find any guidance on the trigger group beyond reading, Dont do it, I made a judgement call to take off a very small portion of the spring. I dont want any unnecessary tension my trigger finger had to pull against. There was one spring I decided to spare in the trigger group because access meant further disassembly. I had pushed my luck enough.
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Since I couldnt find any guidance on the trigger group beyond reading, Dont do it, I made a judgement call to take off a very small portion of the spring. I dont want any unnecessary tension my trigger finger had to pull against.

I've been poking around in the trigger group for my own project. As I understand it, the pawl and trip function independently if the trigger/lifter/sear block. So even if you left the pawl and related parts out, your trigger pull is the same. There may be a very small level of friction between the sides of the trigger rubbing the trip and likewise the sear block rubbing the pawl and the inside of the frame. Those 1911 guys would be stoning all the sides of all those parts which rub. :D

 

The little spring inside the trigger and lifter assembly doesn't add to trigger pull weight. That whole assembly remains rigid during firing and the little spring only gets compressed after the trigger is pulled and the sear block releases the firing pin. As the bolt travels out of battery, it pushes the disconnector downward which in turn compresses that little spring.

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I can tell you this- the trigger pull is far better, and the bolt is much more tolerable. I don't have a trigger gauge, but I popped the rounds off pretty fast, which I couldn't do before the job. When you look at the assembly as you pull the trigger, you are expending energy compressing the lifter spring, and it's excessive. The key is to not defeat the purpose of the spring, while making it less of an obstacle for your finger to overcome.

Edited by ltcajh
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Sarco did not reply to an email, tech support had no real opinion on solving the problem with the 50 round drum, and the returns guy didn't return my call. I filed a dispute on the purchase. Never again Sarco!

 

I loaded up the 30 round stick with handloads to test for functionality. I pulled the trigger as fast as I could (finger got tired at the end). 29 flawless rounds, with the bolt locking open on no. 29. Can't complain too much!

Edited by ltcajh
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Don’t think so.

 

The pawl spring pushes UP on the FRONT of the pawl, pushing it UP. If the front is UP, the rear is DOWN. The rear of the pawl can’t catch the bolt if it’s DOWN. A stronger spring would hold the rear of the pawl down with more force, making it LESS likely to inadvertently float up and catch the bolt.

 

Check for a weak or missing spring, or a pawl that is sticking because it’s gunked up, bent, or rubbing on other parts in the trigger group.

 

My 2 cents, good luck with your project. Tim.

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  • 3 weeks later...

I bought the pawl spring, had the trigger assembly apart, and wouldn't you know it, I couldn't find the spring! Well, I had the original pawl spring I had shortened just a tad, and looked at my springs on hand. I slipped a Harbor Freight spring over the original spring, and it works!

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  • 1 month later...

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