Machining a slide from bar stock

Does anyone have an idea where one can have a new slide made from ‘scratch’? I have a pistol that has been out of production for decades. Spent the past half year trying to find a replacement slide to no avail. Drew a blank w / Gunparts, Jack First and several used part purveyors. No luck on forums related to the manufacturer either. No luck on machinist drawings either so it would take some reverse engineering. Cast stainless so I believe welding is out too.
As you can see at the tip of the paper clip there is a crack on the underside of the slide starting at the breech face and tapering off to the side of slide. The crack doesn’t show on the breech face or in the extractor slot above the crack when slide is right side up. I removed the extractor and from what I can see under 10 power magnification it is only on this surface on bottom of slide.
I’ve been thinking I could drill & tap one or maybe two #2 or #4 machine screws from the outside of the slide through to the center of the slide and tap them into the center block between the slot below the extractor and the ejector relief cut on the other side of block under the bore for firing pin I can’t cant understand the purpose for the slot on the bottom of slide below the extractor. Nothing on the frame appears to ride in it. I could put a small block of steel in the slot, drill & run my screw(s) through it too.
I don’t think the crack resulted from an over pressure load. The breech face doesn’t restrain the base of cartridge case and there isn’t any sign of the crack on breech face. Dimensionally the space between the slide rails is constant, which seems to indicate the ejection port side of slide didn’t start to blow out. I’m inclined to think my crack is a result of poor casting quality since ( I’ve read) this pistol was one of the first all stainless steel pistols made and has been know to beat itself to point of failure.

I guess I’m looking for
1) knowledgeable opinions or alternative ideas on my repair idea,
2) a reason for the slot machined into the bottom of the slide on the extractor side
3) a machinist that could make a new slide.

I could just drop $1,200 or so on to replace this pistol but I could also wind up with another pistol having the same or bigger problem. I realize my repair would destroy the pistol’s value. A new slide wouldn’t help value either. I just really like shooting this pistol and would hate to write it off.
Thanks


Attachment 246891

What is the make and model of that pistol?

If you find someone that wants to do a pro bono assist it will be cost effective. If you pay going shop rate machining a new slide is going to be very very expensive. Cutting out the crack and tig welding might be a better option.

Never used them but I believed they do this type of work. https://www.bunkerarms.com/?fbclid=I...inM8-dQFEjkAVE

If you can find the actual Stainless it is it should be able to be veed out pre heated and welded. TIG would be best probably then refinished. THe problem will be 1) finding out the grade of stainless for sure and then the matching filler. Pre heat should be done in an oven set slide in when cold and bring up to temp about 45 min soak after temp is reached.
Im wondering if this slide is a casting if instead of a crack its a flaw in the casting. Investment cast parts should weld the same as the same grade bar stock.

To be honest that crack may stay like it is for thousands of rounds. If there was stress between the cavities when it was firing, and now the crack has allowed the stress to focus into surrounding metal, it may never get any worse.

On top of that if you dupe the slide in 416, what's going to keep the new one from cracking in the same place? If it is a weakness by design, seems like the new slide would share that by design as well.

Personally, and this is coming from a 50yr welder with plenty of experience with stainless of various grades, it may have cracked all it's going to. I'd shoot it some and keep an eye on it.

It would be different if the crack was in a thin place like the ejection port, or if it ran crossways through the breech face, either of those scenarios would be worse because then definitely it would have compromized the integrity of the slide at more important parts than where that crack is.

Additional information
Pistol is an AMT AutoMag III, Guys on the AMT forum state slide & frame are castings. A retired aerospace machinist I know verified slide is a casting. An old gunsmith inspected and thought the crack wasn’t something to be concerned about. I tried to find a test facility that could determine the extent of the crack but no one was interested unless I had dozens to test.
I determined it was a crack by using a c clamp with wood blocks to squeeze the slide on either side crack. Under pressure a minute line of oil appeared on the crack.
Guess I’ll measure the inside width of the slide adjacent to the crack and check it after a session at the range. With the exception of an occasional mag or two of factory loads I’ve purposely fed this pistol mild (13.7 gr. of 4227 under a 110 gr. RN bullet). That’s one full grain under max load, and still cycles pistol & my M1 carbine.
I’d still like to know the purpose of the machined slot the crack is on.

And you have tried

High Standard 5151 Mitchelldale ,Suite B-11 Houston , Texas , 77092 . Phone 1-800-272-7816 or 1-713-462-4200

Extractor cut above it in picture? Possible prior stress/bad area in material between the two now machined areas? Looking as big as I can expand on computer it seems crack heads for the base of that 90 cut. An NDI buddy anywhere? you know it's cracked just were does it stop? Stop drill crack with a .030" or so bit and let her eat.

I wouldn't run a cracked slide especially if its in the breech face.