Smokeless loads in blackpowder guns?

[Bazoo]

I’ve seen many contrasting reports as to whether one can safely fire smokeless ammo in a blackpowder gun. For sake of argument, let’s use the single action army and the Winchester 73 as basis for my question, but the question is general as to all black powder cartridge guns and I’m happy for specific examples of other guns and calibers.

I’ve seen that blackpowder and smokeless have different pressure curves and that’s why a BP cartridge gun isn’t safe with smokeless. I’ve also seen where Elmer Keith apparently used the old 45 colt guns with smokeless and he made no mention of it. I’ve also seen in Cartridges of the world where they offer a smokeless recommendation for a black powder duplication load and the admonition that pressure must be kept low in the old guns. I’ve also read the same other places but cannot remember now the reference.

Is there a source anyone can reference as to why you cannot use smokeless in BP cartridge guns. I mean a real source like a lab, a reloading manual, or an article where folks have done extensive testing and not just a “because” reference.

I don’t have any BP cartridge guns, I’m just curious about it.

Thanks.

Bazoo

[M-Tecs]

Lots of firearms produced in the blackpowder only era are safe with low pressure smokeless. Lots of others are not. The early Colt Blackpowder iron frame 1873's are recommended not to use smokeless in them. I have read Colt never authorized iron frames for smokeless usage. The 1873 Winchesters have been fired with smokeless for well over a 120 years. Same for Trapdoor Springfields.

https://castboolits.gunloads.com/sho...tique-Colt-SAA

[Walks]

I and other Cowboy Shooters have fired A WHOLE LOT of smokeless thru old BP guns. But ya gotta know yours and the guns limitations.

[Bent Ramrod]

Keith recommended black powder only in those surplus Indian war SAA Colts that the Army had refurbished with mixed parts at the Arsenals and then dumped on the surplus market. But he was after the 900 ft/sec factory velocity there. A safe smokeless load might do 825 ft/sec, and somebody wanting to get full speed with his parts gun with smokeless might get into trouble.

Also, back then, many of the smokeless powders on the market, like SR-80, were very ”twitchy,” where a slight increase in weight might result in a large increase in pressure. Modern powders are better characterized in this respect.

As long as one is careful, a safe smokeless load can be made with most firearm designs. But one needs to accept that there is a certain risk to be managed and act accordingly.

Unfortunately, “Safety,” like a lot of other concepts, has become a growth industry these days, with an over abundance of virtue-signaling. The less you can do, the “Safer” you are, until you fall over dead from boredom. Also, the liability lawyers circle like sharks, so any recommendation could be perceived as a future litigation problem. And black powder loading has been revived for the old guns and cartridges, and is no longer the lost art it was in the teens, twenties and thirties, when smokeless loadings took over.

The handbooks issued by the ammo and reloading manufacturers have safe smokeless loadings for the old rounds, and those are the ones to check out. Internet recommendations should be viewed with the most jaundiced of eyes.

[Bazoo]

So it’s a gun by gun thing. I always wondered about it. And I was reading sixguns earlier and it got me to thinking on it.

Thanks for the replies all.

[Larry Gibson]

"I’ve seen that blackpowder and smokeless have different pressure curves and that’s why a BP cartridge gun isn’t safe with smokeless."

That is entirely dependent on what burn rate of smokeless is used. All powders, including the various grades of BP, have "different" pressure curves.

[M-Tecs]

Not all smokeless is created equal. In the early transition days BP, semi-smokeless and smokeless they offered bulk smokeless powders that were a sub for BP. Some were volume to volume the same. Some were not.

https://www.vintageguns.co.uk/magazi...keless-powders

Bulk powders were made so as to deliver the same pressure as the equivalent volume of black powder. This was useful; as a loader could use the same measure for loading his cartridges whether using the standard 3 drams of black powder, or an equal volume of, for example, ‘E.C.’ powder.

[gc45]

WALKS HAS IT RIGHT! Here is my example: 36 lbs and counting of AA5744 in many old Winchesters made before 1900. Model 76, 86, 1885.. Also in two old Ballard rifles, one sharps and three early springfield trapdoors..All in reduced loads of course. Reduced loads of H4198 is another and one I use in my trapdoors quite often...