Slide shortening

[satkinson]

I want to make a pistol about 1/2 way between a Commander and an Officer's, say 3 7/8-4". Reading Nontes "Pistolsmithing", he talks about two ways to shorten the slide. First is to cut it off from the front to length and then use a piece of the tunnel off the cutoff to lengthen the tunnel rearward. This method loses the front sight and requires remachining the bushing lug slot.

The second method he mentions is to cut an "L" shaped piece off the front, thus including the rearward portion of the tunnel, shortening and then welding the piece back on.

What I want to do is neither. I want to cut the slide off right at the rear of the existing tunnel, then cut off the front of the remining piece, (like a section out of the slide), shorthen the tunel on the piece cut off and then weld the front back on. This will preserve both the front sight and the bushing lug groove.

The only reasons I can see not to do it that way are strength (weld all around the slide) and having to file the weld out of the slide grooves. I plan to laser weld, so I think the weld will be stronger than the 4140, and I don't think it will be a big trick to file the weld out of the grooves.

Am I missing something here?

[1911Tuner]

Sounds like a lotta trouble when you could just call Springfield and see if they'll sell ya one of their 4-inch Champion slides...or just buy a Champion.
Of course' if you're doin' this for its own sake, and enjoy the challenge, try to find a copy of George Nonte's book "Pistolsmithing." It outlines what's involved from start to finish.

[satkinson]

I have Nonte's book, as my question indicates. I propose to do it differently from either of the ways he suggests. I am going to take a section out of the slide between the back of the tunnel and the locking lugs, thus preserving the front sight and the bushing lug recess. This seems to me to be a no-brainer, but there must be some reason it is not suggested by Nonte.

I am doing this because I have a RIA surplus to needs. I have a Commander, but want something maybe 3/4" shorter. Plus, it'll be fun.

[Hawkmoon]

I am doing this because I have a RIA surplus to needs. I have a Commander, but want something maybe 3/4" shorter. Plus, it'll be fun.
You must be gonna do it for the fun aspect, because a Commander has a 4-1/4" barrel and an Officers has a 3-1/2" barrel, which IS 3/4" shorter than the Commander.

Considering that I believe the Commander and Officers slides are exactly the same dimensions from the rear of the tunnel to the back of the slide, it strikes me that you're making a lot of work to avoid doing the obvious -- which is, as you've noted, to chop off the front of the slide and remachine for the bushing and the front sight.

What about taking it out of the middle of the tunnel? Maybe someone has the accurate dimensions of both slides available. If not, I can strip a couple of pistols and measure.

[satkinson]

I will go a little longer than 3 1/2". Plus, I already have the pistol. Seems to me my way is easier, because I eliminate the remachining of the lug groove and installation of the new sight. The recoil spring will be the tricky part. I will try a cutdown Commander spring.

If the Commander and the Officer's rear tunnel to back of slide dimensions are the same, then my intermediate should be too. If you know the dimensions, they'd be helpful.

If you took it out of the middle of the tunnel, you'd have to add back to the tunnel. The ticket, I think, since the tunnel will end up shorter, is to start the cut at the point on the tunnel which will make it the right length and go rearward from there.

[Hawkmoon]

Let me check those dimensions for you. I may not get back to you until tomorrow, hope you can wait that long.

[Paratus]

I did several or these type modifications many years ago, so long ago I don't remember all the details. I do remember that when I sectioned the slide the weld never finished the same as the rest of the slide. Chopping the front and having the bushing lug recut was a no brainier.

[satkinson]

I'll probably finish it with one of the heat-curing epoxy finishes from Brownell's. My laser welding guy tells me, though, that he can use the same 4140 for the weld and it should be invisible when polished.

[John]

Scared! I won't go near a gun with a re-welded slide, no matter what!

[satkinson]

John, one of the methods discussed by Nonte (the "L"-shaped cut) involves a weld in the slide anyway. Modern laser welding technigues result in a joint as strong, if not stronger than the slide itself.

[Herb Clark]

Building a fixture to maintain alignment of slide grooves and sequencing the welding to minimize distortion is critical. Keep in mind that you will be welding material with a varying thickness and making a full penetration weld without blowing through the back side will be difficult. Suggest copper back up bars to minimize excess weld penetration.

[Hawkmoon]

John, one of the methods discussed by Nonte (the "L"-shaped cut) involves a weld in the slide anyway. Modern laser welding technigues result in a joint as strong, if not stronger than the slide itself.
Most welds are stronger than the parent metal around the weld. That's part of the problem. If the weld results in embrittlement of the adjacent metal, the part fails not at the weld but adjacent to it.

[satkinson]

Maybe the entire slide should be re heat-treated after welding?

[Hawkmoon]

Okay, folks, I had a chance to do a bit of measuring and to draw up the two slides in AutoCAD. The Commander slide is an Essex, simply because I already had one with no receiver so no need to strip a pistol. The Officers slide is a Colt M1991A1 Compact. Here's the tale of the tape:

http://i39.photobucket.com/albums/e193/AguilaBlanca/Slides_2.jpg

Allowing for slight discrepancy in location of slide stop and take-down notch locations between Colt and Essex, it certainly appears that all the difference was cut out of the front, within the length of the recoil spring tunnel. The dimension from the back end of the tunnel to the back end of the slide is the same for both.

[John]

Darn, let an architect come up with perfect plans! What an artist!