buzz,
There lies the problem. Of the uncounted number of barrels (did you count them?) burst at trapshoots that you attended, no data was collected. Was the problem with those guns a poorly altered chamber, hot loads, reloading mistake, obstruction, or even a flaw in an unaltered barrel?
Tonight I measured a few unaltered Parkers barrels. The forcing cones of course added barrel thickness while it constricted the bore. Any constriction will raise pressure. The barrel tapers would have allowed me to lengthen the forcing cones to be parallel to the taper from 1 and 1/4" to 1 and 1 & 1/2" leaving the SAME barrel wall thickness as at the end of the chamber. Were I to lengthen the chambers by 1/4" I would not have reduced thickness by much because the tapers were not abrupt. Personally, I'd rather lengthen a forcing cone as that will allow a longer plastic cased shell to be fired while also reducing pressure within the pressure vessel (from the breach to the pressure seal on the wad). Lengthing a light British 12 ga 2 1/2" to a 3" magnum would be dangerous but more so just plain dumb! Aside from teh increased and unpleasent recoil of a 3" magnum fired in say a 6 lb "game gun", the 2 1/2" load has a lower mean working pressure than our good old USA 3" magnum at 11,500 PSI.
The point of the above paragraph is that properly done, lengthening chambers and forcing cones can be with the safety margin of a shotgun. I will concede that improperly done, a dangerous gun may be created. When in doubt, measure. It seems that far too many barrel failures were never measured to determine the problem. Heck, mandating a proof house for a few dangerous guns would be something similar to taking away drivers licenses from everyone over 70 years old! Most 71 year olds are pretty safe drivers.
I shoot many Damascus barreled guns. If one believed the stories about the weakness of Damascus their fingers would fall off if they even picked up a Damascus barreled gun! Some of us know that is far from the truth. Some of my heavier barreled Parkers and LC Smiths will occasionally fire modern factory hunting loads.
I also have a Parker Damascus 10 gauge with British 3 and 1/2 Ton proof marks. If affordable I'd send a few other Damascus guns for proof just for the fun of proving to the naysayers that good quality Damascus in good condition can be as strong as fluid steel. But then, that would be another story...
PS: I've been close to munitions from .17 caliber to those field pieces and rockets measured in inches for as long as you in both my personal and professional life. A friend did mistake blackpowder for PB and on his 4th shot blew a hole in a LAMINATED barreled early Remington double. He had those loads tested and they were at 24,000 PSI. That was a lot of pressure for any gun and it took 4 shots to burst the barrel a few inches ahead of the chamber. Other than than I can reall never being on hand when a chamber burst. A photo of my friend's blown barrel is in Murdelak's book SHOOTING FLYING.
Mark
Last edited by MarkOue; 12/21/11 09:29 AM.
