doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Birmingham Proof House

I sent an email to the Birmingham Proof House inquiring about the proofs on my vintage British double. I received a reply asking for a photo of the proof marks which I provided and I was then told when the gun received its nitro proof (1968), that it was then 2 1/2" and approved for 3 ton. I was impressed and very greatful for the information. Nice chaps, those British.

Interesting place the proofhouse. There is a story and some pictures on this link; hope you don't mind a link to another outdoor site. http://www.modernsportsman.com and scroll to second article on homepage.

I go down there quite a bit. They have a very interesting museum there and do accept visits by arrangement usually catering for parties of 10 or so. Very litle has changed since it started back in 1813. Their Archivist, Bill Harding, wrote an interesting book on Eley Cartridges and is just in the process of completing one on Kynoch and other Birmingham ammunition makers. Worth a visit if you ever cross the pond. It was probably Bill who sorted out your query. Lagopus.....

lagopus,

Thanks for the link. A very interesting and informative account.

Pete

Wow the only gun that could handle the 20 bore shell in front of a 12 bore shell was the Baikal,interesting. Rich

Yes, Lagopus, it was indeed Mr. Harding.

Thank you, very interesting reading. So even Nitro proof is still done with black powder.

In the article black powder was stated as used for "Provisional Proof". This I think is partionally due to considerations of ignition as the bbls are not yet chambered but fired from a priming chain of powder. Also I seem to recall reading that a heavy charge of coarse grained BP gave a better pressure curve for testing the entire bbl than was possible with smokeless. for a number of years I think definitive proof was done with a finer grained BP, but seem to think that smokeless is now used instead.
It is also noted that according to Winchester when they developed their Glass Fiber wound bbl with steel liner it withstood being fired with a 20ga ahead of a 12ga, so the Baikal is not the only one to have ever done so.

Further down the article states:

"The Definitive proof takes place in another adjacent shed where the gun, minus stock work, is laid in a cradle and after being covered with a ballistic blanket, is fired by means of a lanyard into a sand bank at the far end of the shed. The proof cartridges are loaded on site with a carefully measured load of black powder and shot."

This was the part that really surprised me.

Regarding the firing of a 12 ga cartridge with a 20ga cartridge up ahead of it, I decided to blow up a 12 ga Noble pump gun a neighbour donated for me to use as a Hunter Safety Course gun. I had explained during my courses that the 20 ga would fall far enough to jam in the barrel allowing a 12 ga to be chambered.
I tied the Noble to a round bale (I live on a farm)pushed a 20 ga cartridge in the chamber and followed it with a factory WW AA Trap load. Tied a long piece of string to the trigger, hid behind a grain bin and yanked the string.
A sort of muffled thump was heard and when I walked up to the gun, it was apparently unharmed. I repeatd this 3 times and could not burst the barrel, although the action had stretched and the bolt was loose in the gun. I wondered if the 20 ga cartridge was not fired, but was blown out by air pressure. This was in long grass and I could not find the 20 ga ones.
So I'm looking for a donated JABC which will blow for sure
Mike

Mike D;
You are absolutely correct. I was trying to read real fast & somehow jumped that. I had read that for many years the proofing was all done with BP, but was thinking I had seen that the definitive proof had been changed. Guess that was incorrect. I believe the definitive proof is fired with a much finer grain powder than the provisional to give greater pressure in the chamber area.