Open Top in .44 Colt

machine gun moran

I bought one of these from the auction side. I put together some loads in Starline brass with fairly soft 200 grain RNFP's and 3.8 Grains of Trailboss. I fired 6 fouling shots and then six at the paper, but the sight picture was poor because of the reflections, especially on the front sight, from direct sunlight. The 15-yard group was 2 3/4 inches. I moved into the shade, obtained a much better sight picture, and the next 6-shot group was 1 1/2 inches, and the same for the following groups. I seem to have found my accuracy load by accident on the first pass.

The load that I used is indicated as about a 9,000-pound load on the Hodgdon website. Their max for the .44 Colt with Trailboss is listed as 3.9 grains, and I didn't think this would be enough to keep the case walls expanded against the chamber walls. It apparently wasn't, because the empties came out with generous burn marks. Hodgdon lists a considerably stronger load of Trailboss for the .44 Special (about 13,000 pounds), and as the Open-Tops are available in .44 Special, the design is good for at least that much pressure. I appears that Hodgdon is tending towards down-loading the .44 Colt, perhaps out of concern that a cartridge may find its way into an original black-powder gun. But with the accuracy that I got with the 9,000-pound load, I dont think I'll change anything. BTW, this load produces about 700 fps.

Thought I'd pass this along, in case anyone is interested in the .44 Colt chambering in an Open-Top.

flyingcollie

For what it's worth, I've been shooting Trailboss loads in a '73 Colt .45, and a '94 Marlin rifle, chambered for LC. Charts indicate a "maximum" load of 7 grains behind a 250 gr. soft alloy cast bullet. I get "burn marks" as well . . . don't know the pressure generated, but this load is supposed to fly at around 900fps.

machine gun moran

It's true, Flyingcollie, that even some stronger loads may fail to maintain a complete seal. I've experienced burned cases with handgun loads in other calibers at pressures of around 18,000, and sometimes with factory-loaded handgun ammunition as well. I wonder if the effect may be partially dependent on the burn rate of the powder. But it still represents gas finding its way in the wrong direction, which is a partial obturation failure. It does not seem to present a significant problem in handguns, other than discoloring the brass (but Lyman cautions that pressure low enough to allow complete leakage around the case may produce stuck bullets in rifle-length barrels).

Hodgdon indicates the max Trail Boss load for the .45 Colt with a 250-grain bullet, as 5.8 grains, for a pressure of 12,700 and a velocity of about 730. This seems to be a conservative-pressure load for many modern guns, but not for an original black-powder gun. I think Hodgdon has geared its data to the limits of the originals.

flyingcollie

Exactly ! For me, the problem is less apparent in my handguns (I shoot the same .45 LC load in a Colt SA and an Uberti Schofield replica) than in the '94 Marlin, as it's obvious at the re-loading bench the Marlin has a "sloppier" chamber. I'd think burn rate would be the issue.

?? Several on-line sources for Trail Boss load charts "agree" with 7-grains under a 250 grain bullet, but I note Hogdon's recommendations are uniformly lower. Certainly it's a different problem, loading for an "antique".

v35

Open top revolvers aren't the strongest arrangements so in the interests of keeping that revolver tight, I'd be using lighter loads and maybe annealing the brass necks to better obturate gas back flow.