Model 69 to 45 cal conversion findings

Well, I have a nice very slightly used model 69 in hand. I got it to explore the possibility of converting it to a 45. Either 45 ACP or a 45colt/acp. I am a 45 fan love moon clips and have converted a 629-1 to a 45Colt/ACP. My 1955 target sports a 44 mag cylinder reamed and milled to accept 45 Colts and 45 ACP. The barrel protrusion into the frame window has been shortened and cone recut to fit the longer cylinder. My Brazilian is now a carbine with 16 1/2 barrel and stock and has a 45Colt/Acp cylinder. As of yet it has a short cylinder made from a model 28 cylinder and will not accept the longer 45 colt loadings. I do have a spare 44 mag cylinder I could rework to 45 and fit to it though.They all work and shoot well.

But onto the model 69. I took some measurements with a good digital caliber.
The cylinder has plenty of meat between chambers, .040 MORE than a model 629, no problem there, but the chamber to outside of cylinder only measures .049 and if rechambered to accept 45 cases (either Colt or ACP), which would remove .012 all the way around the chamber to take the chamber diameter from .457 to .481. the outer wall thickness would become .037. A N frame 45 cylinder has an outer wall of .072. Of course there would be no cut for the cylinder cut in the 69 like in the N frame. You would end up with about the same amount of material as there is at the deepest part of the cut. But, the cut isn't the entire length of the cylinder either and the extra material around said cut helps support that area.

I don't like how thin the cylinder wall would become. I know Taurus has done it with their similar sized 5 shot revolver. I have a 5 shot 44 special Taurus 431 and it has a slightly smaller cylinder than the Model 69, but the same outer wall thickness for each chamber as the model 69. It also has a forcing cone with a smaller OD than the model 69.

In conclusion I do not believe it would be a good idea to convert a model 69 to 45. Especially not to 45 Colt as I load mine to higher than factory pressures for my N frames. I wouldn't want to chance a 25,000 psi 45 Colt round in such a thin chamber. Even +P 45 ACPs are above 20,000 psi. so not a good idea in my opinion. Darn, I wanted to do this. Now, I have ended up with another 44 mag. Oh, well.

Steel,

Thanks for taking the measurements. I have been looking at all the pictures of 69's, wondering. Visually, it looked to be on the thin side. By measurement, I would tend to agree, too thin. While you might get away with SAAMI spec ammo, the appeal to me would have been more along the lines of 45 Super, or slightly warmer Colt.

Wonder if you could pick up 30 thou on the frame opening. That would mean an oversized cylinder, but if possible wonder if S&W might consider that as a long term possibility.

Hows the ratchet clearance look? That would be another piece of the puzzle.

Craig

The ratchet clearance would also be very tight for moon clips. The S&W ratchet is way larger than my Taurus ratchet. It actually has small scallops in it for the 44 mag rims, but 45 colt rims are the same size as 44 mags, so would work for 45 colt, but moon clips would be iffy.
The frame clearance. The cylinder is 1.562 and the frame opening is 1.600, so only .038 clearance, I didn't go out to shop and get feeler gauges but less clearance on top than bottom. So, with out enlarging the frame window a larger OD cylinder will not work.

Not impossible if S&W wanted to do it.

I do wish they would make a 5 shot 45acp with some alloy components. I really like my CA 44 Bulldog. Small light, big bullets. But, it ain't a S&W or a 45.

This site list many normal J,K,L and N frame dimensions
Smith

Lists the L frame as being .838 where the barrel threads through and mine reads .872. So they did enlarge that a bit to get the heavier forcing cone on the 44 mag model 69. I doubt they would enlarge the window and the cylinder to make a 45 cal L frame. Not enough of us would pony the $ for one.

.45 Schofield?

As I already have a CA Bulldog and a Taurus 431 which are both 5 shot 44 specials with 3" barrels and appox K frame sized. I will leave the model 69 as is and use it as an lighter alternative to my 4" 629 converted to 45acp/colt, my 6 1/2" 25 in 45colt/acp or my 6" model 629 when I want to pack a more powerful weapon. Options are good. I do like moon clips and 45 but, I can live with 44 spec. I also have a 3" model 36, so no shortage of Concealed carry guns.

By, the way the Taurus 431 an all steel gun has a very nice action and compares well to my smaller S&W revolvers.

It seems you've already discounted the conversion based on cylinder dimensions. If you could get past the cylinder wouldn't the 69's two piece barrel present a whole other set of problems?

Adios,

Pizza Bob

Bob,

I think this where folks like Bowen can jump in and perhaps get creative. Give them a good base for a reasonable start, and off they can go, if so inclined.

Steel, I just checked my newer 625 PC. My cylinder thickness is more like 0.085. And while I love the 45 Super performance, it sure would be nice to be a less less closer the edge. Certainly not much less.

It would not surprise me to see S&W try and tap this part of the market. They have certainly addressed the "snubby" 45 market to an extent. They have gone lighter, smaller sure does seems like a logical progression. If you are gonna continue to innovate in the revolver market, sooner or later a small big bore will shake out as a possible direction. Surely at least enough to ask the question.

Craig

Pizza Bob said:

It seems you've already discounted the conversion based on cylinder dimensions. If you could get past the cylinder wouldn't the 69's two piece barrel present a whole other set of problems?

Adios,

Pizza Bob

Click to expand...

The 2 piece barrel would not be a problem. I would just machine a .452 blank to match the .429 insert. I was going to make it a 3" barrel if I did the conversion, but that would have just meant making the insert shorter and reworking the "shroud" The barrel could be removed by using very low temp solder to fill the bore with a piece of sq stock inserted in it.