Gerard
(.224 member)
15/03/07 04:37 AM
Re: Overstressed Rifling

Bear in mind that a jacketed lead soft point is just as hard on a barrel as a jacketed lead solid. With both types the bullet will compress lengthwise under pressure and try to expand radially. This adds to the pressure of engraving the bullet and on the barrel wall as the bullet moves down the bore.

Drive band bullets, solids as well as expanding, resist lengthwise compression almost completely and therefore do not add to the pressure on the barrel wall through radial expansion. The shaft of the bullet is not engraved to any significant depth, only the drive bands are pushed aside by the rifling.

An easy test. Take the temperature of a double that has not been fired for a couple of hours. (Lay a standard freezing point to boiling point stick thermometer on a barrel next to the top rib.) Fire four shots (two shots per barrel) with jacketed lead core bullets, within a timed minute. Put the rifle in the shade and lay th thermometer on the barrel with the mercury at the breech end. Check the temperature a minute after shooting. Let the gun cool to the start temperature and do the same test with drive band bullets. I have not done this with a double but I have done it with a bolt rifle. Anyone want to place bets on the outcome?


This does not mean that all shooting with lead core bullets must cease immediately. Just that the life of any rifle is finite. Sooner or later it comes to the end of that life. Sometimes sooner and sometimes later. The choice is always yours.



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