49North,
From you have written your gun has 1887 to 1904 Birmingham proof marks. They would also appear to be for a normal chamber i.e. 2-3/4" or less. I assume it would have had a 2-3/4" chamber not a 2-1/2" one as its proofed for 1-1/4oz. However - as MIke points out - there can be exceptions (even today it's not unknown for the proof houses to stamp the wrong thing!).
I think the 'guide' weights listed in an earlier post for 2-1/2 to 3" chambered guns are a little on the heavy side. Many 3" guns (proofed for 1-1/2oz) weighed only 7-1/2 to 8 lbs. It's quite possible to find 2-3/4" guns around the 6-1/2 to 7 lb mark. Yours has probably lost a little weight over the years anyway - if only due to the barrel work!
I have in front of me now details of a Jeffrey BLNE with 30" barrels & 3" chambers (1-1/2oz proof) with a 15" pistolgrip stock it weighs in at 7-1/2 lbs.
Doublegunhq,
You mentioned the 14/1 & 16/1 related to the muzzle diameters. Yes between 1875 & 1887 both bore & muzzle diameters were marked if choke was present, but in terms of 12B 14M plus the words "not for ball" (I didn't think fractional sizes like 14/1 were used prior to 1887). In any event W J Jeffery started in his gun retailing business around 1890 - i.e. after they stopped marking the basic muzzle diameters to show choke was present - in 1887 they changed to use the word "Choke" (which is on 49North's post 1887 proofed gun).
49 North,
Why your 'as proofed' bore sizes are so different from each other is strange - why they are so much tighter than the expected "12" or "13" (for a 12 bore chambered gun) really is even stranger.
14/1 = 0.701" to 0.709" whilst 16/1 = 0.669" to 0.676".
The only gun I can recall seeing with such uneven original proofed bore sizes was a ball & shot gun (which I assume yours never was).
There's very probably work been done on the barrels so you'd be wise to take the good advice already offered to you by the gentlemen above & get the barrels properly checked. I hope you'll let us know what you discover.
Regards
MJF
