I'm not too sure what the monoblock is. If it's the back of the barrels (where the rim of the shell holds onto) then yes, there is a visible seam where the chamber was reduced.

Yes. That is called "sleeving" or "Monoblocking". Basically, the original barrels are cut off in front of the chambers or monoblock and then new tubes are sleeved in. Do you know if your gun was originally fitted with Damascus barrels? If they were, they should have a "D" stamped on the flats.

No I don't think it was. I'll check in a bit.

Chris - you should consider joining the PGCA at the Vintage Cup shoot at Addieville East Farm in Mapleville, RI at the end of September. It is a wonderful, three-day, international event with hundreds of guns for sale, lots of sporting clays and five-stand shooting, and lots of yarns and lies to swap.

I'll definitely consider it. Hopefully I'll have a car/my license by then :rotf: The only things stamped on the flats are the patent date (October 25th, 19(23?)) and the letters OV

It could have been a #1 frame 16 completely rebarreled to 20 at the factory.

Do you know what frame size it is?

It should be a 1-Frame Trojan judging by the OV stamp.

What is the serial number?

Measure the exact distance between firing pin centers in sixteenths of an inch to determine frame size.

I'm fairly certain it's a 12 gauge frame, but I could be mistaken. The serial number is 233781

OK then, it would be a 2-Frame Trojan. Sorry, thought I read 16 ga somewhere here.

Oh no you did, it was originally a 16 gauge gun. I think. Can I measure just by opening the action or do I need to disassemble the receiver?

EDIT: I think it's either a 1 or a 0 frame.

EDIT 2: It's a 1. It says 16 as well. What is an OV grade? Under the serial number it says OV. According to the Parker I.D. system on this site, the grade is on the watertable. The barrels are Trojan grade steel.