doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Shooting Damascus

Saturday I shot a round of skeet with my 120 year old English, hammerless, sidelock, ejector, damascus Bozard & Co., using
2 1/2" RST Max Lights which I believe are less than 5,000 PSI. They are, of course, very soft shooting. Now, the gun was originally proofed at 3 tons. According to a table from Ballistic Products 3 tons equals 6,720 PSI. The gun was nitro proofed in Birmingham. Am I correct in assuming that a 6,700 PSI nito load is appropriate for this gun?
I would like to make 2 1/2" reloads. Ballistic Products does not offer a load under 8,000 PSI. Where can I find a recipe for a light 2 1/2" load?
I also shot my RBL 28 that day. Light as it is it was very comfortable. I'm happy with it. The standard wood looks better than I thought it would.
Thanks,
Richard

6720psi is simply a multiplication of 2240 lbs (British Long Ton) by 3 tons psi. This does not give a proper conversion to modern day psi's. 3 ton crusher pressure when given as psi by modern piezoelectric gages will read very near to 9,000 psi. Especially considering the age it should be given a thorough examination to insure nothing has been done to "Take it Out of Proof" as bore honing, chamber lengthening etc. Also note if this gun has a 3-ton stamp upon it, that was not put there 120 yrs ago. The 3-ton mark was not introduced until around 1954, I believe. In view of both old metal & wood one certainly does not have to run "Max" allowable loads. 7/8-1oz of shot at around 1100fps can be very effective loads. Loads of this nature are readily available with rather fast powders @ about 6,000 psi. These are my preferred loads for guns of this type. I personally will not use slow powders at very low pressures, except black.

rgh2, unless your gun has very short forcing cones, it will handle light, low pressure loads in 2 3/4" cases just fine. It is much more convenient to load 2 3/4" as compared to 2 1/2". A roll crimped 2 1/2" loads just about like a fold crimped 2 3/4". Unless you are really hung up on shooting 2 1/2" hulls, I'd recommend you use 2 3/4" hulls and the light, low pressure loads found in most loading manuals.

Richard,

At issue here is proof pressure versus service pressure. The loads you actually use (service pressure) should be well under the pressure used to proof the gun. Believe, subject to correction, that the consensus is that service pressure is 2/3 of proof pressure so your 5,000 psi loads would be about right.

Here's a quote from the London Proof House web site:

"Proof firing. Guns that pass examination are taken to an enclosed firing room, where they are secured in a holding device, which is aimed into a “snail” bullet catcher, a box containing a lubricated and hardened steel spiral that can safely dissipate the momentum of a bullet. The snails used at the London Proof House are safe for bullets upwards of .50 calibre. The gun is then loaded with a proof cartridge that, depending on the type of gun, will produce 25% to 50% more than the theoretical maximum service pressure. the firing chamber is closed, and the gun is fired remotely."

Regards, Tim

From a lot of personal experience I second Rocketman's opinion. You'll find 2 3/4" hulls a lot more conveninent to reload. I shoot 'em all the time in guns made as early as 1870 and have never had any difficulty.

Note that when 3-ton is spoken of in regards to a 2½" chambered British gun, this is the "Service" load, not the proof load. The big question here is has this gun been re-proofed for 3-tons or does it carry only Black Powder Proofs?

Would 2-piper please tell me what powders he's been loading? I've been using 7625 and have started to see its shortcomings.
Thanks

I use 23 gr 7625, 19 gr Pb X 1 oz loads with AA and STS cases.
In Federal paper and Federal with fiber bases I use 19 gr. Green Dot.
All seem to work well.

I have been loading primarily Green Dot. There are also some good light loads using Red Dot. Many have reported good results with PB which has a similar burn rate to GD & there are similar powders by other makers. I am firmly of the belief that powders slower than this should be used at pressures below about 8K psi, "Only" in hot cases (AA, STS etc), with a hot primer, & then only in warm to hot temperatures. I am fully aware there are those who disagree, but they may change their minds one day. A 7625 load taken directly from the manual giving 1¼oz shot about 1125-1150 fps @ around 7K psi, put up in Rem SP cases with Power Piston wads & CCI primers, totally let me down in a duck swamp with temps in the 20sF one day. This was back in the late 70's & was still DuPont powder. Then later upon learning of the distinct possibility of a secondary combustion producing an effect very similar to an obstruction & with the possible result being a burst bbl, I totally swore off of slow burning smokeless powder loads giving low pressures.

Thank you all. I find the information about the dates of the 3 ton stamp on the barrel flats most interesting. I assumed it came with the original London proof somewhere around 1890. If it didn't exist then, it must have been added with the Birmingham nito proof.
I am confused about PSI and PSI by the piezoelectric system. These two expressions of pressure are substantially different.
Does the 3 ton stamp on my 1890 gun mean regular PSI or piezoelectric PSI. It seems to matter a great deal.