I want to to change the lead to bismuth. I'm in CA, nontoxic is mandatory. If the waa wad can hold the increase in bismuth shot ,will that increase PSI?? Any feedback is welcome..thank you!!
So go up to a 1 ounce shot charge?or from #7 shot to #6?Research indicates that Bismuth, 83 on the periodic table, although slightly heavier than Lead, 82 on the periodic table, is somewhat less dense. An increase in shot size of 1 1/2 times is recommended to approximate lead shot performance, so the shot charge should be somewhat reduced in pellet count and weight. Pressure accordingly should be ever so slightly reduced, although many other factors can come into play whenever chamber pressure is addressed. In a strong modern shotgun I would be comfortable subbing the larger sized Bismuth by volume in the Lead wad column, all else being equal. I would however start with the lower recommended charge and be diligent about observing any changes that would indicate pressure increases. Most Bismuth is mined outside of the US, unfortunately, but here in Idaho the gold, silver, and stibnite mining areas seem the best places to go prospecting for some. That could be fun.
Thank you Sir.The size difference is more extreme than that. American number 7 birdshot is .100 diameter and runs 297 pellets per one ounce. A 150% increase in weight would take you up to number 5 at .120 diameter 170 pellets per ounce. That is to equal the individual pellet energy produced by the lead load. Bismuth, I understand, is not very uniform and not very round but it performs better than it looks. I think the 1 ounce load would be the better one because of pellet count, using some bismuth approximately #5 in size. I would use whatever volume of bismuth that would fit into the 1 oz shot bushing, and disregard the weight. The rest of the components can stay unchanged. Go old school and shoot a tin can at the average distance you will be shooting. When you hole it, you are shooting hard enough to reliably take birds.