Krakow Kid,My comments were an expansion of the issue raised by," Old Farmer" namely, "the one year lag between the perfection of choke boring and the introduction of the,Not for Ball, Proof mark".
You can check for back boring of a muzzle loader as follows.
Using a dial bore gauge[I use an Eggerton-Chubb gauge] set to a precision master.With this gauge you can measure the inside diameter of the barrel upto 20 inches from the muzzle.The readings seen will indicate the presence of choke in increments of .001 inches.The Barrels of the gun, if of British make, will be marked with the proof diameter [eg;12, this equates to a nominal diameter of .729 inches].To remain in proof the barrel diameter for this example should not exceed.740 inside diameter.If the measured diameter was for example .750 and yet the muzzle diameter still measured .729 it would be reasonable to say that the barrel had been back bored to create upto .021 0f choke.At the same time the proof diameter maximum would have been exceeded by.010 and thus rendered out of proof!
My advice is take your gun to a qualified gunsmith and have the barrels inspected and measured with special reference to the bore diameters and wall thickness.Take no chances with your safety.
Last edited by Roy Hebbes; 04/15/11 01:56 PM.
