Barrel Wall Thickness

[Austin W Hogan]

Adding the numbers on Dr Drew and Robin's sketches give a breech width of 1.205 inches. Two 1.205 diameter barrels would be 2.410 inches; a two frame is 2.375 across the standing breech and most Parker barrels look like sewer pipe when compared to an English gun.

Best, Austin

[Dean Romig]

Originally Posted by Austin W Hogan

and the chamber wall thickness of most Parker barrels look like sewer pipe when compared to an English gun.

Best, Austin

Sorry Austin - I thought your statement needed a little editing

[Austin W Hogan]

I just took the micrometer to the chamber wall of a 1 1/2 frame DH which is a little under 7 pounds. It measured .190 inches. There must be a lot of lightening holes in those 6 and 6 1/2 pound English twelves if they have a .287 thickness. I think the diagram is in error; adding .080 for the difference in bore diameter and chamber diameter makes it a little closer, but not quite as thick.
A three frame ten is .245 at the breech.

Best, Austin

Added; Bill is correct, a flat or dovetail is cut to join the barrels at the breech removing about 1/8 inch from the breech width.
I just measured a three frame 12 ga barrel. The chamber wall is .265 inch thick. The barrels are stamped 5 12

[Bill Murphy]

Austin is right and the diagram is wrong, at least for a breechloader. No English bird gun has .238 chamber walls. A second thing to consider is that the barrel wall thickness at the chamber is not doubled at the inside in most double guns. Austin's .190 chamber wall dimension is way less than .380 between the chambers of a 1 1/2 frame Parker. The one I just measured is only about .308.

[Tom Brown]

Just to clarify things, what should the thickness of the choke wall be for imp. cyl, mod, imp. mod, or full on a 0 frame 20 gauge Parker? I measured the thickness of my choke walls except would like to know what other choke wall thicknesses measure. Thanks in advance. T.

[Austin W Hogan]

The thickness of the barrel depends primarily on the frame size with respect to gauge, and secondarily on length. The barrels were finished by longitudinal hand filing to fit a general set of outside diameter checks. The filing was generally done to balance the gun at the hinge, but it could be muzzle heavy or light if the customer ordered. The longitudinal hand filing produced barrels that were not necessarily concentric with the bore, and wall thickness can vary side to side or top to bottom. There is no standard thickness.
Some guns appear to have thick barrels because full choke barrel muzzles are .040 or more thicker than the bore.

Best, Austin