I have a Charles Boswell with a serial # of 39XX, which according to British Gunmakers V1 means it was made between 1872-1883 at the 6 Chapel Pl, Upper Fore St, Edmonton. However the Damascus barrels have the 126 Strand Street, London address. All serial numbers match except the trigger guard which as a 63xx serial number. The proof mark is very hard to see, but appears to be a London proof mark prior to 1875. The gun has the Lancaster Slide & Tilt w/underlever and the Lancaster style "noseless" hammers.

I'm just guessing here but as they moved to 126 Strand in 1883, could the gun have been built and finished from some parts which had been stored in a workshop for a number of years ?
I've heard of similar things happening but don't know how common an occurrence it was.

Could have been rebarreled at some point. That might explain the different things you noted. Many guns were returned to the maker or another gunsmith to have a new set of barrels made. Then they would be sent out for proof. Rib address would be current location at the time unless requested otherwise. Trigger guard could have been replaced another time. If done by the maker I would expect a matching number so it had to be a take off. A cheap repair using parts on hand.

Makes sense, although Nick's answer is also a possibility. Thanks to both of you for providing an answer.

Some ideas;
Firstly I believe it was the practice often to take out the number when the order was taken, but there would be a bit of a delay caused by manufacture, fitting, proof etc, so actual completion and delivery might easily be a number of months later
Secondly, I don't know Boswell's history in detail, but the move may have involved being at two addresses during a transition period. Strand is a 'shop' type address/area. Possibly a workshop remained in Edmonton?
If the barrels were replacements, I would expect a later number to have been taken out for them I think.
Trigger guard sound like a replacement 'borrowed' from a later gun.

Some ideas;
Firstly I believe it was the practice often to take out the number when the order was taken, but there would be a bit of a delay caused by manufacture, fitting, proof etc, so actual completion and delivery might easily be a number of months later
Secondly, I don't know Boswell's history in detail, but the move may have involved being at two addresses during a transition period. Strand is a 'shop' type address/area. Possibly a workshop remained in Edmonton?
If the barrels were replacements, I would expect a later number to have been taken out for them I think.
Trigger guard sound like a replacement 'borrowed' from a later gun.

Interesting, but the last serial number from Edmonton was in the 9000 range, so a gun with a serial number of 39XX would have remained in the Edmonton shop for a lot more then a few months.

Alternatively the gun was made with serial number 39xx during the early part of production, it came back for a repair to the trigger guard and then at some point when production was moved to 126 Strand the gun was re-barreled. In the end I doubt I will ever know for certain the circumstances that resulted in the gun having serial number that doesn't match up the address on the barrels.

Are the barrels smokeless/nitro proofed ?

Doesn't Chris Batha hold the records for Boswell?

No, they are Damascus and beautifully browned

Some, but not from that time period and Chris Batha has seen this gun, although he didn't have much information other to say it was the better of the 2 grades that Boswell made in that time period.

Chris Batha's records start around late 1898 at around 13,000. Chris found the records for 13549. It was made Sept 1, 1899.
Chris stated that is was about the earliest records he has.
I used to have a Boswell SLE 12290. Chris couldn't date that gun.

I have a damascus 10 hammer gun SN 7016. It has patent dates from 1877. The proof marks are pre-1887. English patents are protected for 14 years. My 10 could have been made between 1877 and 1891, the proof marks further restrict the range to pre-1887. I just tell folks, the 1880s.

My 10 ga does have the Edmonton address. I have a Boswell trade label that is correct for my gun. It is not in the best shape.
It says: C. Boswell, Gun and Pistol Maker, Upper Edmonton, near London. And "old guns taken in exchange"

Joe in Charlotte

Ah, thanks. just wondered if the original barrels may have failed a nitro re proof , then been replaced along with the top rib.