Re: re-contouring barrel
Yah...old fart. (We are about the same age. I went in in '62 at age 22. My first ship was the Everglades AD24...Destroyer Tender out of Charleston.) I'll try to say what I intended to do in shorter form. (As I understand it.) This doesn't apply to cut rifled barrels such as Mr. Hart made. Only to buttoned or hammer formed (cold swaged)barrels. I believe the Remington 40X's were/are buttoned.) In those barrels, when you turn them to a smaller diameter, the bore will sometimes tend to enlarge due to stress relief. If you turn a buttoned barrel on a taper from the chamber to the muzzle, there is a tendency (NOTE-not an absolute number) for the bore to enlarge. Which can make it larger at the muzzle than at any part back toward the chamber. With soft lead bullets, there is little to no elastic memory... when you swage a soft lead rimfire bullet down to a smaller diameter by passing through a tight bore spot, the bullet does NOT re-expand to fit the bore. So...if you have a tight chamber fit and the bore enlarges as you get toward the muzzle and is therefore larger at the crown, accuracy degrades due to a smaller bullet in a larger bore. Jacketed bullets due to the gilding metal jacket, do tend to rebound a bit in diameter, so that they are not as sensitive to enlarging bores. (I.E. "blunderbuss" shaped bores.) By not turning the last 1 to 1.5 inches of the barrel, thereby keeping the muzzle inch or inch and half of length the original diameter, the muzzle bore diameter doesn't expand, and the bullet, if it passes though a loose spot back up the bore that was caused by turning the barrel down, will fit the bore more closely as it exits the muzzle, retaining the accuracy of the original barrel. Now you know all I do. For more information go to Rimfire Central. Great site and much more knowledge than I. Anchors asway. FNP
