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I am reading Matthews book the paper jacket and I think I am getting myself confused. I think he is recomending a CB that can be just pushed down the barrel and make ever so light rifling marks on the bullet. The bullet should "ride" the flats of the rifling and the rifling should just cut the paper which will fill the void to the Bore and act a the gas check. So the only thing that "digs" into the rifling is the paper and the bullet turns if the paper is well attached? I am patching a unsized lead lee .312 185 gr. RN. Raw it is more like .314 and I will patch it and drop it into an 8mm. I've got this on paper using freezer tape but now with his book I am going for real paper and groups smaller than the pie plate. Any help would be apreaciated and if you wish to talk me down from this madness I will listen. JB
Years ago I was paper patching .45 cal bullets for a Harold Fuller (Cooper Landing, AK) .45-2 7/8 Sharps that I had. The paper needs to be double wrapped -- in other words, two layers, and must butt together precisely. Try different thicknesses of paper from "onion skin" to high quality "rag bond" and see what happens. I never got hung up on paper thickness vs groove/land diameter -- I went for accuracy. You want to dampen the papers on a sponge before wrapping them on and then twist the tail. The tail may be cut off with fingernail clippers when dry. When you settle on a thickness that works well then make a template for cutting future patches. In the beginning, just wrap three layers of paper around the bullet and cut through with a razor blade, leaving the top and bottom edges intact. When you unroll the paper you will have three section; two of which together are your patch size.
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Rezdog, I understand the paper jacket, it is the pellet size that has me confulsed. There is a bore and grove diamiter in each barrel. Matthews is saying the bullet needs to ski on the lands on the rifling and the paper will give the bullet the twist. That means that the bullet will be around 10 thousandths smaller than the caliber. A .308 will shoot a .290 pill or a .323 will shoot a .314. That is what I read in his book but not stated as simply. I want someone to confirm what I think he is saying.
The idea that you start with a bullet that nearly falls through the barrel and then patch it up makes sense and it doesen't as well. JB
As I recall, those old barrels that shot paper patched bullets had shallow rifling. When I bought my old rifle (long gone) it was missing the original mould so I bought a custom one from Hoch and I think I went land diameter. In any case those bullets will upset to fill the grooves and I can't imagine that rifling marks will be detrimental (they don't bother any other bullet). I would take whatever bullet I had and experiment with different thicknesses of patching, even trying a single layer (as I recall, that is called a "Chase" patch). Some years back the NRA conducted a series of tests with PP bullets in the .30 cal range as I recall. If you can find it, it will answer a lot of your questions. Good luck!
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The rule is ,Smokeless powder: bullet size same as bore size and then patched to groove or 1 or 2 thou over groove size the alloy would be 1:20 or harder.
Black powder: my 50-90 likes, patched bullet size the same as bore size (patched bullet can be pushed through the barrel by finger pressure alloy 1:30 or softer
The sledge hammer effect of BP will upset the bullet to groove diam.
My 500 A Square shoots a pure lead bullet to 2000ft/s with 1 1/2" 5 shot groups at 100Y
Hope this helps Martin
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