Pressure in a shotshell

[Bindlestiff]

Originally Posted by Pete Lester

Case in point. Sherman Bell's data for the Short Ten shows a Fed Hull, Win 209 primer, 32gr of SR7625 with SP10 wad and some filler for both 1 1/4 ounce lead and 1 1/4 ounce of Bismuth. The lead load uses a folded crimp and generated 6700 psi. The Bismuth load using a Roll Crimp (which reduces pressure) generated 7100.

When loading shells, the shot is measured by volume and listed in ounces. I suspect the volume/ounce conversion is for lead. Do you think Sherman weighed or measured his Bismuth load? If he measured the shot and given Bismuth is less dense than lead, the Bismuth weight would be lighter than 1 1/4.... but generated higher psi. What would that indicate?

[J.B. Books]

Originally Posted by Robin Lewis

When loading shells, the shot is measured by volume and listed in ounces. I suspect the volume/ounce conversion is for lead. Do you think Sherman weighed or measured his Bismuth load? If he measured the shot and given Bismuth is less dense than lead, the Bismuth weight would be lighter than 1 1/4.... but generated higher psi. What would that indicate?

Since Bismuth loads are stated in weight and not volume I have always used an adjustable bar or a modifed mec bar that throws the desired of weight of Bismuth. I have never heard of anyone doing otherwise.

An equal weight of bismuth to lead is going to have a taller shot column.

PS. I am pretty certain Sherman weighed his Bismuth loads, the evidence is the difference in amount of filler wad needed for the same weight loadings vs. lead.