Lead vs Bismuth in reloading

[Matt Valinsky]

I have not used Bismuth for reloading and have no knowledge of the beast, so the reason for my question.

I have found a 16ga. recipe which I have all required components, Cheddite hulls, cheddite primers, SG16 wads and Green Dot powder. In this particular recipe the playload is 7/8oz. of Bismuth which I don't want to reload, I would rather use 7/8oz. of lead. I have read that all things being equal that 7/8oz. of lead will generate lower pressures than 7/8oz. of Bismuth. from what I understand it's a volume thing.

So, my question to the folks who know the answer, is this true?

In the Bismuth recipe with 15.5 grains of Green Dot the average velocity is 1221 fps and average pressure is 5803 psi., this is a tested recipe.

Thanks in advance.

[CraigThompson]

I’ve loaded bismuth a fair bit . But in the 10 gauge 2 7/8” . I used the same 1 1/4 ounce load as I use for lead using SR7625 with the exception of weighing on a scale the 1 1/4 ounce of bismuth to go in each shell . I also found with the more coarse #1 , #2 and #4 bismuth I didn’t seem to need the spacers to take up room in the bottom of the shot cup .

[Pete Lester]

I have not used Bismuth for reloading and have no knowledge of the beast, so the reason for my question.

I have found a 16ga. recipe which I have all required components, Cheddite hulls, cheddite primers, SG16 wads and Green Dot powder. In this particular recipe the playload is 7/8oz. of Bismuth which I don't want to reload, I would rather use 7/8oz. of lead. I have read that all things being equal that 7/8oz. of lead will generate lower pressures than 7/8oz. of Bismuth. from what I understand it's a volume thing.

So, my question to the folks who know the answer, is this true?

In the Bismuth recipe with 15.5 grains of Green Dot the average velocity is 1221 fps and average pressure is 5803 psi., this is a tested recipe.

Thanks in advance.

Bismuth delivers higher pressures than lead, because with equal weight there is more bore scrub (friction) as the same weight of bismuth has a larger volume.

An old rule of thumb is you can take any lead recipe and substitute the same VOLUME of bismuth and get similar results. If you should do that you are in untested territory but I have never heard or read anyone who had a problem by doing this.

If you substitute lead for bismuth in a tested load in theory there should be less pressure, given the very low pressure of your chosen bismuth load substituting lead may lead to bloopers and squibs especially in cold weather.

[Matt Valinsky]

Bismuth delivers higher pressures than lead, because with equal weight there is more bore scrub (friction) as the same weight of bismuth has a larger volume.

An old rule of thumb is you can take any lead recipe and substitute the same VOLUME of bismuth and get similar results. If you should do that you are in untested territory but I have never heard or read anyone who had a problem by doing this.

If you substitute lead for bismuth in a tested load in theory there should be less pressure, given the very low pressure of your chosen bismuth load substituting lead may lead to bloopers and squibs especially in cold weather.

I thought it had something to do with volume but never connected the friction aspect.

Thank you for the knowledge.

[Pete Lester]

I thought it had something to do with volume but never connected the friction aspect.

Thank you for the knowledge.

Just don't substitute the same VOLUME of lead in a bismuth recipe and expect lower pressure because you would be increasing the weight of the shot charge.