Originally Posted By: L. Brown
Originally Posted By: AmarilloMike
If I were shooting loads with fiber wads in competition I would not want lengthened forcing cones. Gough Thomas Garwood contended that the long forcing cones sometimes allowed gas to escape around the (fiber) wad and weld the shot together.

I wouldn't worry about lengthened forcing cones if I were shooting modern plastic wads with shotcups.

Best,

Mike


Mike, can you point to the specific source of your Gough Thomas reference? I have 3 of his books and I can't remember reading anything about the forcing cone issue--but it could well be I've just forgotten it.



SHOTGUNS AND CARTRIDGES, third edition, page 136

The question then arises, why not a really long cone- five or six inches maybe - by which the pellets would be gently eased back in to the bore? Such cones have been strongly advocated, notably by that doyen of American shotgunners, Elmer Keith. They would certainly lower ballistics (Journee lost 33ft/sec of muzzle velocity by lengthening cones from about 3/8 inche to 1-1/4 inch), but might well achieve a net gain with high-pressure cartridges by the improvemnt of patterns. Superior patterns are worth than marginal values of muzzle velocity.

Years ago, it was the practice of many of our best gunmakers to bore their guns with what could fairly be regarded as a prolonged extension of a normal cone. This was a tapered entrance -- perhaps 9 or 12 inches long - from the cone to the bore proper. In a high-class specimen which I have measured, the bore diameter immediately in from of the cone is .738 inch tapering down to .730 inch at 10 inches form the breech.
But long cones rely absolutely for any merit they possess on the high quality of the wadding. If the wad does not expand adequately immediately on its emergence from the case, a long cone will invite gas to escape past it, and if any considerable amount does so, bad patterns, accompanied by serious balling, are almost inevitable. Here, two of the virtues of the modern full plastic wad stand out conspicuously; the skirt wad provides an efficient gas-seal, and any gas that does escape is prevented by the shot-cup from invading the pellets.

I remember some other remarks by him on this subject - more to the point about balling and written before plastic wads became commonplace

Best,

Mike

Last edited by AmarilloMike; 04/01/11 07:19 PM.

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