Over bored barrels

[John Truitt]

As a continuation from a topic found in Mr Lesters post.

12 ga chambers in a 10 ga bored barrel. I understand that some trap shooters are doing this with modern guns.
Mr Romig makes reference to Parker doing this early on. I guess things truely do come full circle. What is old is new again so to speak.
Has anyone had any long term experience with this combo?
How about 20 ga out of a 12 ga barrel?

Just curious.

[J.B. Books]

I don't think in practice it would be much different than using 12ga gauge mates in a 10ga gun, 20ga gauge mates in 12ga etc so there should be some experience with performance on the board with this.

Surprisingly ATA rules govern the chamber, no larger than 12ga, and not the bore, so way overbored barrels are legal. See page 49.

http://www.shootata.com/pdfs/2011_rulebook_4web.pdf

[Pa SxS]

It's not only bore diameters that have come full circle. Ever look at how a Seitz, Silver Seitz, and Ljutic shotguns break their barrels open? These are all high end trapguns. They open with a mechanism located in front of the trigger guard. Sounds like Parker had a winner with their underlifter design. 100+ years ahead of the rest.

[Ray Masciarella]

In modern times, Mossberg makes a 12 ga with overbored to 10 ga size barrels. Give great patterns for turkey hunting when good ammo is used. Otherwise, I have never been impressed with the quality of the gun itself.

[Double Lab]

A couple of months ago I purchased a Wm. Ford 20ga. hammer gun with 30" tubes. In my research of this gun and it's maker I learned some interesting things. You are right on John, things do come full circle. Not much has changed as far as shotgun bore/chamber improvements . Wm. Ford was a maker of fine damascus barrels for the trade including some of the big London names. The barrels on this delightful gun were made under the "Heath chamberless system". The chambers are 20ga., the bores are 16ga. and the 4"chokes are 18ga. with no forcing cones. .019(IM)/.028(Xfull). Barrels were measured with a 12ga. barrel mic. Mr. Ford put his barrels on a Boss back action. The recoil with this gun is extremely mild with standard 7/8oz. skeet loads and virtually non-existent with my 3/4oz., low pressure handloads, all loaded in 2 3/4" hulls. I own a number of 20ga. Parkers and none of them recoil less than this gun. I guess what's old is new.

[AmarilloMike]

I have a Purdey hammergun that started out as a 14 bore percussion gun in the 1840s. In the 1870s it was returned to Purdey and they converted it to a breechloader. It has 16 bore chambers and was intended to use the Kynoch thin wall brass shells. The inner diameter of the Kynoch 16s were about the same as 14 bore. I shoot Magtech brass shells in it now and they are also thin wall.

It was common in England when converting muzzleloaders to breechloaders to go to the next smaller chamber because the outside diameter of the barrels didn't allow for the chamber size to match the bore size.

Amazing how much trouble they went to to reuse those old barrels.


Best,

Mike

[Leighton Stallones]

I have an 1894 Remington 12ga trap style double with original .752 bores . My 1881 Parker has .750 bores. I think it was done quite often.
I have a 10 bore Grant that Briley put 12 ga chamers in and it works great with plastic wads.