Talk to me about slide to frame fit

jacotsmith

jacotsmith

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Hi everyone,

Back when Armco was hot-rodding Norincos, I had Gunnar (and Clarence) work on a few guns for me. I always liked how tight and solid yet smooth the guns were afterwards, with not the slightest trace of any former rattle.

With a 1911, I always assumed that the rattle-killing was mainly accomplished by two things: bending the sear spring so it exerted constant pressure on the grip safety therefore eliminating any wiggle (and therefore rattle), and fitting the barrel bushing. On the latter, I never knew if they just fumbled in their spare parts drawer for a bushing that fit more snug or if some mechanical process was used to actually reduce the ID of the existing bushing. I may be way off on my assumptions, I know zero about gunsmithing, but that's what made sense to me.

However I never could figure out what they did to the SIG P-series clones to tighten up the slide to frame fit. I have some guns that rattle like crazy and are reliable as the day is long, such as the current Glock 19 I've been shooting for a while now, and the rattle doesn't bother me at all. But I have other guns that I wish could be tightened up.

So all that said, what is involved in tightening up slide to frame fit on a steel/alloy (non-polymer) frame pistol? I can't see changing the recoil spring having the intended effect. Does a gunsmith literally put the slide in a vice and squeeze it a few mm at a time until it is the right fit? I have one pistol that was home cerakoted by its previous owner in bright fire engine red (God knows why) and the cerakote is so thick that there is super fine red dust on the inside of the frame whenever I field strip it, so I would assume too tight of a fit is a bad thing.

Anyway, this is just one of those things that I know nothing about but have always been curious and want to understand better. If anyone cares to educate me I would love to hear your experience.

Thanks for looking!
 
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I actually read a while back about a guy who tightened his frame slide fit by building up beads of metal on the frame by welding where slide runs and then grinding/hand shaping it back down until it was the perfect fit. I don't know what that would do to the structural integrity but supposedly it worked out really well for him. Might be harder to do on something that isn't pure steel though.
 
Proper way is weld/recut the slide and frame rails. Dirty way is squeeze the slide in a vice, or peen the rails.
 
Because of the widespread use of the 1911 for target shooting, there is a huge body of knowledge about how to improve their accuracy. Doing a high grade job doesn't involve only swapping parts.
Usually slide/fame fit is adjusted by upsetting metal and refitting.
Lots of information available about how to do this. Kuhnhausen's book is an example.
You can also go to Brownells's website and view the different tools, and what is done with them.
 
tiriaq said:
Because of the widespread use of the 1911 for target shooting, there is a huge body of knowledge about how to improve their accuracy. Doing a high grade job doesn't involve only swapping parts.
Usually slide/fame fit is adjusted by upsetting metal and refitting.
Lots of information available about how to do this. Kuhnhausen's book is an example.
You can also go to Brownells's website and view the different tools, and what is done with them.
Click to expand...

This is the answer to the OP's question!
 
All things being equal, I like a tight gun with no rattle. But depending on your objective, I'm not sure it would be worth the trouble to create that after the fact. It won't add accuracy as that is not the critical connection. 1911s were designed to have some slide to frame play for reliability. Solid slide to barrel lockup is more important for accuracy. I had a colt special combat government with surprisingly loose slide the frame fit but had a 1" test target at 20 yds or so.
 
I have a nork that was so loose it would rub the finish off the slide on one side as it cycled, would deflect enough to one side that the side of the slide would rub on the frame. Rather than clearancing the frame I tig welded 2 1" long beads on each side, front and rear of the frame slide rails (front and rear), and re-cut the rails. To be honest, I love a tight 1911, both my nighthawk and STI are very tight with zero rattle or play, but had the nork not kept scrubbing the finish off, I'd have left it. It is what it is, and accuracy was decent after fitting a new bushing and some adjustment to lug engagement. Almost all accuracy in 1911s come from barrel to slide and bushing fit.
 
Thanks again folks. To be clear, while I'm curious about 1911s, what I'm really trying to figure out is how fit is improved to SA/DA type semi autos, like a P226. So far it sounds like either adding material to the frame rails or squeezing the slide in a vice are the main methods.
 
The barrel locks into the slide and the slide has the sights mounted on it. So by rights it's not a super big deal if the slide rails have a bit of play provided the barrel locks up consistently in the lugs of the slide and the bushing or slide nose is a nice low clearance fit on the nose of the barrel.
 
jacotsmith said:
Thanks again folks. To be clear, while I'm curious about 1911s, what I'm really trying to figure out is how fit is improved to SA/DA type semi autos, like a P226. So far it sounds like either adding material to the frame rails or squeezing the slide in a vice are the main methods.
Click to expand...

Generally the frames are peened with peening bars. Not squeezing the slide in a vice. The peening bars are selected based in the rails on the slide then the frame is peened down onto that bar. The better way would be to rig the rails and recut them.
 
Alright, got it. Peening more better than squeezing. The pistol in question is plenty accurate and a great shooter, I just find the loose fit and rattle irritate me as in all other respects it is a top notch firearm. I guess though if it continues to bother me and my OCD gets the better of me off to the pistolsmith she goes. But at least now I have a better idea of what's involved. Thanks CGN!
 
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