.357/44 Bain & Davis

[GunslingerDK]

I know this forum is mostly for automatics, but i hope there is a gunsmith here who can give me a few tips.

I looking to convert my 9mm Ruger Blackhawk cylinder to a .357/44 Bain & Davis. I have the reamer but my problem is that I can't find a gunsmith to do the job. The 2 best in the country don't have time, and the 3rd best refuses to do it, and then there is a few that I don't trust... so my list of possibles grows thin.

I know 2 guys who have a company, one is a very skilled machinest and the other is a gunsmith. I think I managed to pursuade them to do the conversion. But I would like to know a little more about the procedure. It took me a year and a half to find a reamer, and had to pay $400 for it in Germany (no US conpany would sell/rent me one). I talked to another guy (yes I have talked to half the country during the last 12 months) he said that the chambers need to be pre-drilled and that the reamer only polished the chambers to the final fit. From looking at the reamer I just assumed that it is used to drill the cylinders, and not just for the final finishing, as the "steps" on the reamer seem to correspond to the shoulder angles on the Bain & Davis brass.

So basically I'm looking for some info on the actual conversion, so i know a little about what has to be done. This is just my paraniod way of ensuring that my reamer is used correctly. When looking at the cylinder and the reamer, it seems like a walk in the park, but then again i'm not a gunsmith and I do not know to which tolerances the cylinder must be made in order to avoid set back issues.

Any help or advice is greatly appreciated!!

Edit: I live in Denmark, hence the limited number of gunsmiths!

Edited November 2, 2010 by GunslingerDK

[Toolguy]

You will have to move a lot of material to get to the .44 size. The chamber reamer is for final finishing. You don't want to try to hog out all that metal in one shot with the chamber reamer. The best approach would be to set up the cylinder in the mill, holding it in precision v blocks in the vise or in a lathe chuck bolted to the table. Use the indicator to make sure that the cylinder is exactly vertical before doing any cutting. Indicate each chamber with a dial test indicator (you can use a mirror to see the face of the indicator when it's facing away from you). Then use a boring head to bore out the .44 part a few thou. under what the reamer will cut and a little short of where the shoulder will be. Then go in with the chamber reamer, turning by hand, using plenty of cutting oil and clearing the chips often. If you don't clear out the chips often enough, you will get rough spots in the chamber where the chips got packed in and scratched it. Depending on how the reamer is ground, it may be a good idea to make a collar with a setscrew to go on the reamer to get the same depth for each chamber.

[Wap wap]

Sounds like toolguy could do the job!!! Had one on these when Bain and Davis was doing it back in the 80's , was suprized to see the subject come up again. B and D did a really good conversion of Mod. 28 to 45LC at that time also. First my experience with the cartridge in a Ruger Blackhawk, except with the 357 cylinder. Forcing cone erosion you wouldn't believe. With max. loads around 24-26 grs. of 296 measurable wear occured under 1000 rds, cylinder gap blast was closer to a 454 although I'm sure the pressures weren't as high. And as with most tapered cases in revolvers cases would freeze up under the right (wrong) circumstances, which were loads under max, when the case would move back against the recoil shield and reform. At that time there was another line of thinking (I think it was called the bobcat) which used a nylon collet around a 357 bullet in a regular 44 case, to get around the set back problem. Dan Wesson a few years later came out with the .357 Max. which did away with the problems of both and become the standard for IMHSA for awhile. It had stainless steel barrels that were easily replaced when throat erosion got bad.

Not to discourage you, it was a fun project--- but

[xpertz]

The people who refused to do this were probably concerned with the amount of material removed from the cylinder, meaning thinner walls, and the extra chamber pressure that a necked down case conversion produces. I believe I would want a little more technical info before doing this conversion.

[GunslingerDK]

You will have to move a lot of material to get to the .44 size. The chamber reamer is for final finishing. You don't want to try to hog out all that metal in one shot with the chamber reamer. The best approach would be to set up the cylinder in the mill, holding it in precision v blocks in the vise or in a lathe chuck bolted to the table. Use the indicator to make sure that the cylinder is exactly vertical before doing any cutting. Indicate each chamber with a dial test indicator (you can use a mirror to see the face of the indicator when it's facing away from you). Then use a boring head to bore out the .44 part a few thou. under what the reamer will cut and a little short of where the shoulder will be. Then go in with the chamber reamer, turning by hand, using plenty of cutting oil and clearing the chips often. If you don't clear out the chips often enough, you will get rough spots in the chamber where the chips got packed in and scratched it. Depending on how the reamer is ground, it may be a good idea to make a collar with a setscrew to go on the reamer to get the same depth for each chamber.

Thank you very much, this was exactly what I was looking for! Now I know a little more about the whole thing, and can pass it along to the guy who's doing the conversion.... when I find him that is.

[NAV]

Did you ever finish the 357-44 Bain Davis I am looking for a cylinder reamer any suggestion? 

Edited August 4, 2020 by NAV