12 gauge bore size question

Ray Masciarella · 12-18-2012, 11:32 AM

I read with interest the bore and chamber size article by Austin in the lastest Parker Pages. It mentioned some live bird guns had a bore size of .740. I have a Parker ordered by a known trap shooter with 32" barrels. Its bores
are .740. It isn't a "live bird" gun with no safety.

I thought it may have been polished in later years but I'm now wondering if it was made that way. Anyone have any thoughts? Would the Parker records indicate a larger than normal bore size?

Thx for any thoughts.

Ray

Twice Shooter · 12-18-2012, 12:36 PM

Ray, I have measured a number of hammer guns with .755 bores. I don't know when they went to .729. Maybe Researcher has information on bore sizes. I have an underlifter 12 gauge with .760 bores that delivers beautiful patterns. Cheers, Tom

Researcher · 12-19-2012, 12:11 PM

It seems like bores are large on early Parker Bros, guns from the black powder years, when the practice of using brass shells with one gauge larger wads was common. In the 1893 or 1894 time frame, when factory loaded paper smokeless powder shells were coming on strong, the Brothers P reduced the bore size and began advertising their guns as "bored for nitro powders". My 1889 12-gauge GH-Grade has bore diameters of .757" seriously overbored, while my 1894 vintage 10-gauge NH-Grade has bore diameters of .779" pretty close to gauge.

The above is very simplified, and things get more complicated when one gets into the 12A & 12B and 10A & 10B shells. Likewise, up to about 1931 all our North American shotshells used corrosive priming, so bores got pitted and polished out on a pretty regular basis, leaving it very hard to state unequivocally how they left the factory. Then throw in that Stan Baker didn't "invent" overboring, it was practiced by various gunsmiths and factories through much of the 20th Century. On and on.....

Twice Shooter · 12-19-2012, 12:59 PM

Hi Dave, Thanks for the info. I once had a Stan Baker manufactured barrel that I bought from Stan in 1986 for a Perazzi single that he had made to .800. I didn't like it and soon sold it. Cheers, Tom

Ray Masciarella · 12-19-2012, 01:42 PM

According to the article, live bird guns were at .740, as well as Super Foxes. I was wondering if a trap gun might also be ordered that way and if the Parkers records might so indicate.

Blind Dog · 12-19-2012, 02:21 PM

Surprisingly, my 50 year old '37 has a .740 bore with .022 choke constriction.

Researcher · 12-19-2012, 03:09 PM

The early Super-Fox doubles had bores of .750" but a bit later they settled into .738". Some later Savage-era Super-Fox doubles aren't overbored at all. From my checking of half a dozen or so Remington Model 31 TC barrels, they were overbored to .744", while regular Model 31 barrels seem to run true to gauge. My Remington hammerless doubles made in 1895 and 1896 have bores in the .741" to .744" range, while my Remington Hammerless Doubles made from 1905 to 1909 have bores pretty close to gauge. I find the Ithaca doubles in my accumulation seem to run overbored up thru 1934, then from 1935 on pretty true to gauge.

I've found some guns with quite tight bores. My 10-gauge Baker $100 Pigeon Gun sports bores of .753" and .752", my 12-gauge Royal Gun Co. single barrel Trap Gun .715", and my 12-gauge Fox Gun Co., Balto., Md., U.S.A. guns .708" .712" .710" and .713". Also, these two Baltimore Fox guns are the only two vintage doubles I've come across that are chambered for the 3 1/4 inch 12-gauge shells. I'd love to hear from others who have an example of these Fox Baltimore guns as to their bore diameters and chamber lengths. My four 12-gauge Frank A. Hollenbeck designed guns made in Baltimore by Ansley's old partners, after he ran off to be a professional shooter for Winchester all have bores very close to gauge and 2 3/4 inch chambers.

Kevin McCormack · 12-19-2012, 04:26 PM

Years ago I measured an untouched 30" CHE 12 bore that had been in the seller's family since its original purchase in the later 19-teens. Both bores measured .750 on the button with chokes of .712 at the muzzles. Length of the forcing cones was around 4 1/2- 4 3/4 inches. I didn't have any chamber measuring tools at that time so can't say if it was a 3 inch gun or not. It was a #3 frame and plenty heavy, complete with two perfectly drilled out, then filled and checkered over, plugs in the SKBP checkering field. When I shook it I couldn't feel or hear anything rattling around, but I'd bet to this day there was weight added in the stock.