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02-18-2010, 08:20 PM
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#3 | ||||||
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Destry's right. A roll crimp will reduce pressure and velocity, but by how much and how you would offset any velocity loss, I don't know. The only thing I use a roll crimp for is blackpowder.
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02-18-2010, 10:27 PM
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#4 | ||||||
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From Bell's article The Forgotten Tens,in the DGJ 12-1. "To see what would happen, I tried a couple variations of this load. Having the test equipment allowed me to get answers to my most frivolous of questions. By leaving out one of the 1/4 inch filler wads, I had room for a six point star crimp on the smooth brass Winchester hull. With the same 38- grain charge of SR4756 powder, the velocity increased from 1202 to1288 ft/sec. The pressure jumped from 8100 to 11,000 psi! This tell me to stick with the roll crimp in my heavy loads for the 2 7/8inch ten-guage shell"
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02-18-2010, 11:39 PM
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He star crimped a brass hull? Now that's a new one on me.....
DLH
__________________
I was as virtuously given as a gentleman need to be; virtuous enough; swore little; diced not above seven times a week; went to a bawdy-house once in a quarter--of an hour; paid money that I borrowed, three of four times; lived well and in good compass: and now I live out of all order, out of all compass. Falstaff - Henry IV |
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02-19-2010, 12:10 AM
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#6 | ||||||
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The smooth brass hull is in reference to the head of the case. " I also loaded the red plastic Winchester hulls,( with smooth brass head), with 1 5/8 ounces of lead shot." This is earlier in the article. However if you try to star crimp a brass case let me know how it turns out.
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02-19-2010, 12:29 AM
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#7 | ||||||
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Ahhhh, that makes a lot more sense. I've seen some factory loaded brass cases that has a sort of light roll crimp and I've got one English one that's got I guess what you'd call a star crimp but it only just barely goes in a bit and doesn't fold completely over.
DLH
__________________
I was as virtuously given as a gentleman need to be; virtuous enough; swore little; diced not above seven times a week; went to a bawdy-house once in a quarter--of an hour; paid money that I borrowed, three of four times; lived well and in good compass: and now I live out of all order, out of all compass. Falstaff - Henry IV |
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