Warmer 38-40 loads ?

[Gunslinger1911]

I just got a Lipseys Ruger 10mm Blackhawk - SWEET by the way !
Has a second cyl in 40 S&W, Thinking about having it re chambered to 38-40, having read it can be hotrodded a bit past 10mm because of the bigger case (yea, I know, don't want them to find their way into a "normal" 38-40.
Any body have any data ?

[MT Gianni]

http://www.sixguns.com/tests/tt3840.htm

[Outpost75]

You might consider instead the 10x25mm Rimmed, made by necking down Starline .44 Russian brass. About 8% more capacity than the 10mm Auto, but no danger it getting into an old .38-40 by mistake. John Taylor has the reamer and can also make dies. DougGuy can also modify Lee .38-40 dies to this for about $150.

252620

Accurate 40-252H bullet using a compressed nominal case full (16 grs.) of IMR4227 produced 1084 fps with an Sd of 12 fps from the 5-1/2" Ruger Vaquero and 1340 fps with an Sd of 24 fps from my 22-inch Bunny Gun. With 21 grains of 3Fg Goex rifle velocity is about 1000 fps.

252623

[nhithaca]

I have a Buckeye 10mm/38-40 gun and the 38-40 brass is pretty thin and does not like even max safe loads. Check the dimensions on a 400 CorBon. Or just deep cut the 40 S&W cylinder to 10mm Mag. Starline sells brass and you reload with the 40 S&W dies. Accurate Powder used to show data. Approaches 41 Mag levels. Make sure throats match barrel diameter or ever so slightly larger (0.400" barrel w/ 0.401 throat for example).

[smithnframe]

Use as much 2F black powder that you can get in the case, put a wad on top and compress slightly when seating the bullet. I shoot a 190 gr cast in my 38 w.c.f. weapons when I shoot them.

[El Bibliotecario]

I have a Ruger with both 10mm and 38/40 cylinders, and while I think the latter round is the caterpillar's spats, its performance can be matched or exceeded with the 10mm round, and without having to deal with the quirks of a 19th century cartridge case. But if one has a gunbelt for 45 caliber cartridges, the 38-40 cartridge has one advantage; it is dimensioned to fit .45 loops.

[Gunslinger1911]

Thanks all,
nhithaca I hadn't even remembered the 10mm mag; looking around the net shows some serious velocity ! Don't even have to buy new dies !!

[nhithaca]

Yes, always wanted to do it to my gun but didn't want to loose the 10mm cylinder. Both cylinders are marked and serial numbered to the revolver and since it is a Buckeye special it does have some value. Since you already have the 10mm and a 40 S&W on a standard Blackhawk it wouldn't matter (in my opinion). Maybe I will find a 40 cylinder to refit to mine and do the rechamber.