doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Best Bismuth and shot size(s)

Two words always come to mind whenever these type discussions come up..................

Tom Armbrust

SRH

I think what he meant by an 1/8 oz less lead is simply that if you load the shot by volume, which is more or less required given the fixed size of a shot shell, then you will end up with loads that are about that much less in weight. But the pellet count will be the same.

Who is Tom Armbrust?

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Tom Armburst provides the service of testing reloads and can tell you chamber pressue and muzzle velocity for a fee when you send him a set of shells to test.

He is a legitimate and safer approach to adapting lead loads to bismuth

Not sure he tests during the winter.

Tom Armbrust
Ballistic Research
1108 W May Ave
McHenry, IL 69950-8918
(815) 385-0037

He does not test during winter. It may be as late as April before he gets cranked back up.

SRH

I just read one of his articles on Bismuth that googled - there was only one that I found. It wan't particularly helpful, but provided some support for the "1/8 oz" issue, which is, as I thought, a density thing when volume loading - a 1 1/8 oz lead bushing is essentially a 1 oz Bi bushing.

He also seems to be a huge fan of buffer, tightly choked shotguns and REEEAAALLLLYYY long range bird shooting.

I have done little with buffers but it seems that I recall it does tend to raise pressures - sometimes substantially?

http://www.armbrust.acf2.org/nontoxicupdate1and2.htm

Yes, Armbrust recognizes by volume 1 oz bismuth fits a 1 1/8 wad cup, he does not state that you should use 1 1/8 lead data in lieu of tested bismuth data. He recommends going to the Hodgdon website for data.

He does provide some load options in 12ga.

Reference buffered loads. Yes, they tend to significantly higher pressures, but if you follow tested recipes you can make some good performing loads. Buffered loads

That is the article I was referring to.

As for Hornady, in cross referencing loads for Bi and Pb using the same powder (longshot), Win AA, W 209, and wad WAA12R, you will find that when the shot and powder weights are the same, pressure and velocity are effectively the same - within a few percentage points.. I

f you load using volumetric measures and simply substitute Bi for Pb, using the same measure will result in a 13-14% reduction in the weigh of the shot column and the pressures drop substantially. In other words, substituting Bi for Pb by weight seems quite reasonable given the Hornady data and substituting Bi for Pb by volume (as most of us do with our reloaders), appears to be VERY safe.

I find no Hornady loads for using buffers, albeit, I'm haven't dug real far. I don't want higher pressures than what I find for unbuffered loads, and I am not going to shoot waterfowl at 60+ yards.

Thank you, I was just going to post loads from Hodgdon using cheddite hulls, primers, and RP wads to illustrate this!!

Back in the early days of steel shot there was no loading data, thanks to people like Tom Roster, and companies like MEC that all changed, I still have some of those old MEC 10 ga wads, but I think because steel acts so much differently than lead, or other heavy metals that act like lead, BI, gold, and yes Tungsten matrix people got scared of reloading, which is a good thing, you CANNOT sub lead loads for steel.

I mentioned it before (in another post) Steel shot when loaded in a confined space and shot at velocity acts like a solid, it does not like being confined, it does not like sudden velocity changes, and it does not like being choked, but you take other materials listed above, when put under the same conditions as those listed for steel they act like a fluid, they will flow with the velocity, they don't mind the sudden acceleration, and they react well to being choked because they "flow".

TM