doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Smokeless loads for 2 & 1/2" 12 Bore

I have an original, Damascus barreled J.P. Clabrough and Sons shotgun chambered for 2 & 1/2" 12 Ga shells. The shotgun is in excellent condition, smooth shiny bores, tight, and still with some case color on the receiver. Gunsmith has inspected the gun and pronounced it in excellent condition and safe to shoot. Measurements of the wall thickness indicate that the barrels are original and have not been honed. I would like to use smokeless powder in this shotgun. I am very experienced in developing smokeless loads for original black powder rifles, but have no experience at all with shotgun cartridges.

I would like one or two smokeless loads that generate peak pressures no higher than black powder but deliver the pellets at original black powder velocities. I have read Sherman Bell's tests of old beater shotguns, including Damascus barreled shotguns, so would prefer not to get deluged with warnings about shooting a Damascus barreled shotgun. I would be very grateful for some direction on some smokeless loads. I have 2 & 1/2" casings, I just need some direction and have not been able to find anything from my usual sources.

Is the gun nitro proof? What were the wall thickness measurements in the chamber and forcing come area? Is it a game gun, or something of heavier construction? These do have a bearing on whether I'd be happy to shoot it with smokeless.
With all the caveats you've identified: any loads that stay in the 5000-7000 psi range ought to be ok; the case length is not an issue - roll crimp the top instead of the fold/star crimp of a 2 3/4" case.

http://www.shotgunworld.com/bbs/viewtopic.php?f=13&t=282211
Here are some 2 3/4 recipes using American Select. Several are 7000 and below. They can be adapted to 2.5" by trimming and roll crimping:
http://www.alliantpowder.com/reloaders/powderlist.aspx?type=2&powderid=2&gauge=12

I don't have the measurements at the moment; they are buried somewhere, however, one barrel is full choke, the other is cylinder. It is a gun for birds and small game. I want to use it for Woodchucks. Regarding using 2 & 3/4" cases in a 2 & 1/2" chamber, it is my understanding (though I have not actually read that particular article) that Sherman Bell did some tests to see what effect a 2 & 3/4" shell had on pressure and found a much higher pressure spike at the throat.

GLS: thank you for that link

Question: For comparison, what was the original black powder pressure? (i.e., where does the 7,000 psi limit come from?)

Kirk, I think if you read the posts again, they are saying what ever load you find for a 2 3/4" hull will work for a 2 1/2" hull that is roll crimped.
The 7000 psi is probably the highest you would want to go and there are plenty of loads you can use from there down. The Hodgdon site has plenty.

I do this for my 1892 W.W. Greener 12 ga. I like to use the Remington hulls from the cheap Game Load to the RXPs, they all load alike.

I'm in no hurry to reload these, I use my 12 ga Mec 600 Jr for the first 3 stages and finish them with an old roll crimper. You can also use the one for a drill press, but I find this just as fast.

Those above are 16 ga. 2 9/16"

Woodchucks?

Chuck if you are referring to the #5's, I use these for my second shot on pheasants. I had some nickel plated stuff to use up.

Chuck, you 'member how that rooster folded I hammered with my short 10? Those were hard 5's gettin' his attention.

KirkD, welcome.

Many of us load low pressure 2 3/4" hulls for our 2 1/2" chambered guns with good satisfaction. The issue with 2 3/4" hulls in a 2 1/2" chamber gun is when higher pressure loads are used. Higher pressure loads tend to have a higher pressure differential than do low pressure loads.

The 7000 psi recommendation is a sort of rule of thumb based on being conservative with black powder loads and service proof as a guideline. BTW, many BP loads have high chamber pressure; they are not universally low pressure as is sometimes said. There are many low psi 2 3/4" loads in the various loading manuals and web sites. Pick one below 7000 psi (more or less) that you have exact components for and have fun. I shot five-stand last Sunday with a Parker "D" with damascus barrels and can still count to ten on my fingers!!

DDA

Thank you all. Very helpful information here. Much appreciated. I do have a roll crimper so it looks like I'm in business.

Last Dollar: Most fellows around here use high speed rifles that fire a bullet at nigh unto 4,000 fps and shoot them from 400 yards away. That makes it way too easy. I like to stalk up to about 20 yards away and then let them have it. I've done this for a number of years with a 20 Bore, but now that I have this old hammer gun, I want to use it for the Woodchucks. They are making big holes in my alfalfa field.