Original bore?

[Keith Doty]

What would be a correct, original bore diameter for a 1901 12 ga. GH with damascus barrels. I know the older 10s were a different bore than "modern", were 12s also different from modern dimensions? Any help appreciated!

[Bill Murphy]

Yes, older 12s were larger than nominal dimensions. However, I think that a 1901 12 gauge gun would be the nominal .729 or .730 when factory original. Someone please correct me if I am mistaken.

[Dean Romig]

I think you’re right Bill.





.

[Researcher]

My Father's 1902 vintage 2-frame VH has bores of .728"/.729". My 1889 vintage GH has bores of .757" but it was back to the Brothers P. at some point as it has the 1910 bolt and bolt plate.

[Bill Murphy]

The larger bores were common in the mid 1890's and I don't know when the switch to nominal 12 gauge bores happened. I have a 1901 gun that has .729 bores.

[Keith Doty]

Originally Posted by Bill Murphy

The larger bores were common in the mid 1890's and I don't know when the switch to nominal 12 gauge bores happened. I have a 1901 gun that has .729 bores.

Steel barrels or Damascus? Or would it matter? I was pretty sure the typical sizes of bores changed right at or before the turn of the century.
I ask because I have what I hope is a "cream puff" GH Damascus on it's way to Texas. Very nice wood, nice barrels (outside), sharp engraving and a bit of case color left, overall a nice gun that's been in a family for many years. I have 3 big concerns.....barrels, barrels, and barrels. Numbers match but is not listed in the serialization book. I have agreed with the seller the deal swings on the barrels being good dimension, thickness and shootable condition to MY satisfaction. A session with measuring tools and borescope when it arrives for a verdict. Thanks All!

[Mike Poindexter]

Austin Hogan published data on this a long time ago. As with most of his research (choke shapes, french polish, etc.) it was so informative that I copied it to my Parker files so that it survived to my posterity. I am attaching it. Bottom line is prior to s/n 70,000, 12 ga bores were commonly in the .755 range, while afterward they tended to conform to the .730 range. Enjoy

[Researcher]

In the 1886 Chamberlin Cartridge Co. ammunition catalog they offered special cartridges for Parker Bros. guns with over-size wads.

[ArtS]

There is a section in TPS that states the "true bore" was adopted as a standard in March 1892 for 12 gauge. The similar change for 10 bore was stated to have changed a few monts later. The passage states that after that date, a 12 gauge with the oversized barrels would be stamped with an "O", presumably for old or oversized.