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Ha HA! Slide fit is MUCH better now


want2race

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History: I had an existing 5 inch Limited STI (I didn't build it), to accurize it I opted for a 6 inch barrel and slide instead of just a new barrel.

Post modification: I was happy with everything except the frame to slide fit. The new slide went right on the frame and had what I consider excessive play. I was never real happy with it, and in fact embarrassed to show off the gun because of it. It was plenty accurate, but doing super fast transitions I could feel the slide moving side to side.

Post, post mod: Although the barrel fit was good, I wanted better. I had coned and fluted my bull barrel (to lighten it) and ran into some "other issues". Good learning experience. When you don't support the barrel during the whole slide cycle, the front of the barrel drops down and increases wear on the hood and the slide - rear of the radial locking grooves. I helped this in an unusual way. Turns out the guide rod was forcing the barrel down as the slide travel forward. I changed to a GI spec guide rod and that solved it. The other guide rod can still be used but I have to modify the rear portion that interfaces the lower lug area of the barrel. I swapped to the GI spec because I'm trying to reduce the nose weight even more. The GI short guide rod weighs about 1/3 of the full length.

I used some standard 1911 frame plates (.113") and peened the frame slightly. Didn't take much and I have a special ball/peen hammer for this (polished). Refitted the frame to the slide and I am a super happy camper. It is now as tight and smooth as if I had started with a virgin frame. Saved me the expense of a trip to an Accu-rail'er.

I O-ringed the barrel, just as I had done with my Chop,Cut,Rebuild STI. Locks up with a "snick", it had very, very slight movement at the front before. It could out shoot me before I'm sure. This was more for CDI factor, and to hone my skill at grooving a barrel on a drill press.

I will no longer feel embarrassed to hand somebody my 6 inch Limited gun.

It was a good day.

(pic from before the frame work and o-ring)

post-8536-1215148535.jpg

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I had some of that too. To get the frame rails to peen down, not just out (wider) I used a smaller plate. I could have used a .114 to just go wider, but I used the .113 to get them to peen downward too. I had to do some clean up with a slide rail file but the results made me smile.

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The o-ring doesn't sit that far back on the barrel. I hope to shoot it tonight or tomorrow. I already know the o-ring will last a while as I've done this on my carry gun (IDPA gun) but I want to see if the POI has shifted. I fit this one a little tighter than the carry gun so I'm using a little bolt gun grease on the oring. The gun was still plenty accurate before, so if the o-ring ever goes south during a stage or match it won't effect it much.

I will put more rounds through my limited gun than my carry gun so this is a sort of a T&E excersise.

Sometimes I have a hard time calling it "done". I like to tinker.

I was thinking about turning the bull barrel down to a bushing barrel, then using an EGW Melted style busing . Lop the bottom off that would normally keep the spring plug in (won't work on my 6 inch) and come up with another method of keeping the bushing in place (besides a super tight fit). With a machine shop this would be easy. Coming up with something that I can do with hand tools and a drill press is a little trickier.

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Talk to me some more about O-ringing the barrel.

I'm going to have access to a machine shop and a talented machinest over T-day break, and this was something I was interested in doing to (at least) one of my CZ's.

You said that you were doing them with a drill press, using a HK o-ring? How did you determine how deep to make the cut in the barrel?

I'm gonna try and order some of those o-rings next week, and play around with them. I like the idea.

- Jeremy (who is proud to see Kentucky engineering in full effect)

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The depth of the cut is key. It's never the same. The depth of the cut determines the overall OD, which depends on the ID of the slide.

Shot it last night. Best group was with 180gr Zero JHP, using a foam block on a table for a make shift rest. .572" CTC for 5 shots. The group looks like a .45 hole and a .40 hole next to it. Freestyle best was .925" or 5 shots, standing shooting 170gr LSWC's. No point of impact shift so at least I know I didn't screw something up. Now if I could only post a pic of the target...

Got it:

Top two groups were LSWC (obviously). 1.060" on the left, .840" on the right.

Bottom groups were 180 JHP. .975" on the left, .572" on the right.

The solo group below the pistol was standing freestyle. .925"

I aim at the 6 O'clock of the squares. Sometimes I get it right, sometimes I don't.

post-8536-1226583638_thumb.jpg

Edited by want2race
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50 yards.

Just kidding. I can't even tell the A zone that far out...

15 yards. The indoor place I go to has shitty lighting and I can't see well enough at 20 to hold a consistant POA.

This isn't meant to replace current methods of accurizing or building pistols. However, if you have a bull barrel built by a monkey (or just worn a little loose) this may be a quick fix to regain some accuracy. My 6" was the latter, just a tad loose after doing all the work to it after the initial fitting. Now I want to see how long one o-ring lasts.

Edited by want2race
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Gotcha, indoor range by me has horrible lighting and is really hard for me to shoot groups too. Resting on the range bag and wondering if the monkeys in the next stall are going to shoot me doesn't help either.

Your gun would appear to me as being accurate enough for what we do.

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I was thinking about turning the bull barrel down to a bushing barrel, then using an EGW Melted style busing . Lop the bottom off that would normally keep the spring plug in (won't work on my 6 inch) and come up with another method of keeping the bushing in place (besides a super tight fit). With a machine shop this would be easy. Coming up with something that I can do with hand tools and a drill press is a little trickier.

Being the melt bushing has all that front face area, maybe a detent ball and spring in the slide face and a dimple on the backside of the bushing face?

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That's a pretty good idea. If I had to do a quickie "at match" repair or field strip I'd worry about loosing the spring and ball. Perhaps a pin instead of the ball, instead of a detent on the backside of the bushing, a stepped hole with the smaller diameter hole all the way through. Small pin (paper clip) used to push in the pin to unlock the bushing so it could turn. Might be tough to pull off the work on a hardened slide with a 10" drill press though.

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