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Joined: Jan 2002
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Sidelock
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Sidelock
Joined: Jan 2002
Posts: 674 |
I am making a .450 BPE single shot and am currently trying to figure out what twist to get in my barrel blank. It is a modern action, so it iwll handle full nitro loads, but I want to shoot paper patched lead bullets. Any input would eb appreciated.
Thanks!
skunk out
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I will turn the question around a bit. Express bullets are light bullets for a higher initial velocity with black powder. That may not necessarily be what you are interested in with nitro powders and so forth. The question then becomes what bullet length do you want to shoot out of the gun? The Greenhill formula of 150 diameters squared divided by length equals the twist required to stabilize it (working in inches). Normally the twist rate would be made 1" faster than the formula recommends.
cheers Doug
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Joined: Jan 2004
Posts: 6,738 Likes: 432
Sidelock
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Sidelock
Joined: Jan 2004
Posts: 6,738 Likes: 432 |
Marc, I have a number of bullet stability/rifling twist estimators and if you would like I would be glad to help you out. As suggested by Doug, you can start with the bullet you want to use, and then work back to the twist rate.
I too shoot paper patched bullets. My .45-100 wouldn't have it any other way.
Brent
_________ BrentD, (Professor - just for Stan)
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Sidelock
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Sidelock
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I am going to be shooting paper patched bullets in the 280-365 gr range. Probably 335-365 90% of the time. Well, truth be told I will likely find a load that I like and stick with it for many years.
Krieger offers 14, 18, and 29 twists - I am leaning towards ordering the 20.
skunk out
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Joined: Jan 2004
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Sidelock
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Sidelock
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Posts: 6,738 Likes: 432 |
Marc, I'm stuck in O'Hare. If I ever get out of here and back home sometime next week, I can work out the details, but a 365 gr bullet is darn short, and a 20 will be more than enough by a pretty good margin. An 18" twist will stabilize a 550 gr 1.45" bullet at slower velocities for a long ways (like 1000 yds). The 20 will do the trik in a pinch.
I'll work out the details early next week if you wish, but 20 will be fast enough. A better question is if it is TOO fast. I do not know what normal twists were for the old 450 bpe with these sorts of bullets. I'm guessing upper 20s.
Brent
_________ BrentD, (Professor - just for Stan)
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Joined: May 2005
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I am guessing that 1:20 is a typo for 1:29 If so that should do for up to about 350 grains bullets. I measured a couple of .457 cast bullets; 310 grains is roughly .8" long implying that 350 grains would be about .9" long. A 450 grains bullet was 1.25" long That translates into twists of 1:36 and 1:32 for the light bullets allowing 1" faster twist than the formula. The heavy bullet would require 1:23 again increasing twist by 1" from the formula.
cheers Doug
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Joined: Jan 2002
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Sidelock
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Sidelock
Joined: Jan 2002
Posts: 674 |
I wound up ordering the 20" twist from Krieger. That is what I had in mind when I called, but before saying anything I asked the guy on the phone what he would reccomend for 280-365 gr cast bullets and he said "20" without hessitation.
Thanks for the input
skunk out
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Joined: Jan 2002
Posts: 92 Likes: 2
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 92 Likes: 2 |
Marc,
I shoot an Alex Henry, and have an original AH mold with inserts for solid point or hollow point, so here goes,
325 gr. hollow point, paper patched, soft lead, 48 gr of IMR 4198 topped by 12 gr. Dacron. The correct BP load is 4 1/2 drams of FG or FFG.
370 gr. Flat Point Solid (same bullet w/o the hollow point) will shoot fine with the above load or can be pushed to 50 gr. of IMR 4198.
Neither bullets are crimped for single shot use as it's not required and would only tear the paper patch and cause leading.
We could meet at the Guild Show next year to discuss this further as several members will be working up the same 450 BP loads or for 450/400 's for the 2008 Guild single shot caribou hunt I announced this year. Maybe you should join up with us.
~Barry~
"A Stranger is a Friend we haven't Met"
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Joined: Jan 2002
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Sidelock
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Sidelock
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THanks for the info Arctic. Sorry I am just now responding-I have not looked on this forum in a couple of weeks.
Is your Henry a single shot? Is it a hammer or hammerless action?
Do you know of anyone making a mould that matches the original Henry mould?
I will actually be using this as one of my"metal guns" for my application to be accepted as a Regular Memeber next January. Would love to meet up with you while at the Show.
skunk out
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Joined: Jan 2002
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Sidelock
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Sidelock
Joined: Jan 2002
Posts: 674 |
Arctic-
PM sent. If you did not get it, please email me at mstokeld@hotmail.com
Thanks!
Marc
skunk out
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