Nice English hammer gun. Out of proof?
 

I looked at a very nice English hammer gun today. It is priced low. The gun does not have a makers name. The chambers measure 2 3/4" with my Galazan gauge. Everything I see on the barrel flats shows 2 1/2" proof.
Am I correct?
Thanks Dave

If the barrels have plenty of material left and no big pits get it and go shoot the thing.

The 1 1/4 ounce proof would usually indicate more than 2 1/2" chambers. What is the bore diameter? Is it still .719?

Have the wall thickness measured. It does not appear to have been London or Birmingham reproofed for 70mm or 2&3/4 as required in the UK. Good luck.

The picture isn’t super clear to me. It looks like it has a British reproof mark on it. I can’t tell, but does that a 5 ton mark? Anyway, have the bores measured to be safe.

Ken

2 1/2" chamber, 1 1/4 ounce original proof barrels are not unknown, but are unusual.

It was originally proved 1925-1954 with 2 1/2" chambers for 1 1/4 oz.
1 1/4 oz. would be the standard for 2 3/4" chambers for a max. service load of 3 3/8 Dr. Eq. with 1 1/4 oz. shot with a pressure of 3 1/2 tons = 10,640 psi
Bores then were 15/1 or .685" - .692"

It was reproved (Crown over R) 1954-1989 by the London Proof House (the arm and sword over NP, but prior to application of the date code mark which started in 1972) still with 2 1/2" chambers for THREE Tons; now with a bore of .719". 3 TONS would be the standard for 2 1/2" chambers with a max. service pressure of about 9000 psi

That is substantial honing so wall thickness measurements are critical.

https://photos.smugmug.com/Proof-Mar...B38C781D-M.jpg

Thank you Drew, That is the information I was hoping not to get, but expecting.
I'll pass on this one
Thanks again, Dave

The short answer is that it was in proof sometime before 1989 after the barrels were opened approximately 3 gauges. As everyone said, you must measure the walls. It could be very thin as reproofed, and may have been honed again for some reason. My bet is that you will find some very thin barrel walls at some point, particularly in the front half.

I edited my post. The application of the date code mark by the London Proof House started in 1972 so the gun was reproved prior to then, and bad things happen to barrels in > 50 years.