doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com UK proof and bore sizes

I'm looking into a sxs made long ago in UK by a good shop. The barrel flats indicate bores measure .729 and .740. It was reproofed in London in 1983 for 2-3/4" chambers at 3-1/4 Tons and 1-1/8 ounces of shot. Cannot see any indication the bore size was changed over the life of the gun. Perhaps the gun required reproof because the bore was .740? (12 ga). The gun is expensive, so it may behoove me to get the original documentation for this gun before purchasing it...

No. It was reproofed because lengthening the chambers requires reproof under CIP rules, generally.

I agree completely with Carcano. As 2.5" cartridges are so hard to find in the USA then many English guns had their chambers lengthened to 2.75" before export to the USA.

It should be fine, but use sensible loads.

HB

Ask the seller for a full size in focus image of the barrel flats, then post, or send to me at drewhausemd@yahoo.com
The proof marks will tell the story, and until post-1954 had a number indicating a range of bore dimensions. It is likely the .740" was part of the reproof after honing.
3 1/4 Tons would be standard proof for 2 3/4” chambers 1954-1989 for a service load of < 10,000 psi

It would be unusual for a 12 bore to be proved at .740 when first made.

Many were originally proved at 13 (.710) or 13/1 (.719).

Let me tell you a story...

One of my clay pigeon shooting pals is now in his 80s. During the 1970s he had built for him a Best quality 12 bore sidelock by A.A. Brown. Those who know will know the quality of his work.
Circumstances changed and he needed to sell it. His gunsmith advised that the best he could expect for it was £2,000 (quite a lot then). However he also said that if he agreed he could open out the chambers from 2.5" to 2.75" and have it reproofed, which might make it more saleable. BUT if it failed Proof then it would be scrap.
So he agreed to have the chambers lengthened, and the gun then passed proof - phew.

It then sold to someone in the USA for £5,000, or about $12,000 at that time.

He now shoots one of the last Webley 700s plus a Miroku MK60 20 bore.

HB

Entirely sensible choices.

A very near 80 year old friend of mine from England just scored a screaming auction deal on a custom Chapuis. He has a few driven hunts planned, and is quite excited to use the “new” gun on them.

I didn’t know whether to be excited at the news of his stolen at auction gun, or the fact that this dude has multiple driven birds hunts planned for this year.

Maybe both.

Best,
Ted

The barrel dimensions of this gun .729 and 740 brought back a distant memory of a gun I came actus in the 1960s . In past times here in Britland it was once legal to shoot deer using a shotgun and a single slug load, to increase accuracy some gun owners had a paradox barrel having riffling for some length near the muzzle in one barrel. ownership of this type of gun is not permitted on a normal shotgun certificate it must be held on a section 1 firearms certificate. To et around this licencing problem the rifling was removed and the gun reproved with the larger bore barrel. So maybe be this is one such gun.