257 Banshee

[gbryn]

In the book precision shooting the author writes an article about his wildcat 257 Banshee.One of the cornerstones for
making this cartridge work, with a powder capacity of 90 gr,
of powder and bullet weight of 90 gr is a powder manufactured from Winchester that came available after the Vietnam war,it was intended for 50 bmg and 20 mm guns,and was slow burning and with a very low flame temperature.
I´m Interested in building a rifle in this caliber so I want to know if anyone knows if this powder is still available or if
Vihtavuori or other manufacturers sell powder with similiar
specifications,

Thanks
Guðmundur Brynjarsson

 

[mikecr]

It's probably military surplus powder. Magic for big overbore boomers. But very, very dirty. Varies considerably from one lot to another, so buy a drum full.
http://t6aluminum.tripod.com/Surplus_Powder.htm
http://www.gibrass.com/gunpowder.html
http://www.wideners.com/itemview.cfm?dir=278%7C283%7C313

If you want ideas about what more common powders would do in the Banshee, Look at Lazzeroni's 'Scramjet' load data. These are very similar, and with same capacity.

 

[gbryn]

Thanks for the info
maybe I should rather consider the Lazeroni
I'm already finding it difficult to find the
RWS 6.5 x 68 brass needed for the Banshee

Guðmundur Brynjarsson

 

[Ackman]

I have that article. It's a lot of trouble to accomplish something that can be done better and much easier. A .257Wby with the right chamber will do the same thing with considerably less powder. A friend's reamer has semi-tight neck and NO freebore. He's done a few 26" barrels that shoot 100's at 3850, which is cooking right along. My 30" Hart barrel shoots 100's at just slightly over 4000. One factor to making velocity is PMC brass.....harder than the other headstamps. Our loads are several grains over loading manual maximum. Another thing when doing the reamer is a shorter than stock neck....the necks are shortened by .040 or .050" so factory ammunition can't be chambered in one of these no-freebore guns. Seated just shy of the lands, a 100gr Sierra bullet is right to the bottom of the neck. These guns will shoot 1/4" without much trouble.