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Old April 3, 2009, 08:43 PM   #1
Missoura Don
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Barrel twist question

Howdy all....I'm sure that you guys that have been shooting for years and years probally hear some questions that are just "normal" knowledge for you, and maybe some of these questions have allready been asked in other threads, but I've got a question that probally has a "common sense" answer, but I cant seem to figure it out, or find research enough that has a simple enough explination....I'm trying to figure out barrel twist, and though I know the basics of rifling, as 1 complete revolution in so many inches, how does a barrel measuring 8 inches, have a "1:30" twist. Wouldnt the barrel have to have a 30 inch barrel to complete one revolution? Like I said...probablly as simple as 1+1 to some of you...but I'm learnin as I go! Thanks for any input.
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Old April 3, 2009, 09:20 PM   #2
B.L.E.
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There's no need for the rifling to make a complete turn within the barrel. If you take a 30 inch long barrel with a 1 in 30 twist, the bullet makes a complete turn in the barrel, if you cut that barrel down to 15 inches, it only makes 1/2 turn inside the barrel but it still has a 1 in 30 rifling pitch.

Look at it this way, you don't have to be 40 miles away from here one hour from now in order to drive at a speed of 40 miles per hour.
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Old April 3, 2009, 09:21 PM   #3
Jim Watson
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The RATE of twist is given. An 8 inch barrel with a 30 inch twist would have about 1/4 turn of the rifling.

Bear in mind that rifling twist is overemphasized on the Internet and overstudied these days. Standard applications with standard twists and standard ammunitions work very well. Things only get strange at the limits.
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Old April 3, 2009, 09:37 PM   #4
James K
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Since this is the black powder forum, I will confuse you good folks with something you might not know. In the days of muzzle loading, around 1850, it was not too uncommon for barrels to have 0 twist rifling, in other words, straight grooves with NO turn. Quite few people at that time still didn't really believe spinning a bullet made it more accurate, but they wanted grooves to hold the black powder crud and let the gun fire more shots before becoming unloadable.

Jim
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Old April 3, 2009, 10:08 PM   #5
madcratebuilder
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Quote:
Since this is the black powder forum, I will confuse you good folks with something you might not know. In the days of muzzle loading, around 1850, it was not too uncommon for barrels to have 0 twist rifling, in other words, straight grooves with NO turn. Quite few people at that time still didn't really believe spinning a bullet made it more accurate, but they wanted grooves to hold the black powder crud and let the gun fire more shots before becoming unloadable.
Jim, I think I ran into one of them on another forum.
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Old April 4, 2009, 04:46 AM   #6
Jim Watson
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I always thought the straight grooved barrels were a good deal earlier, like maybe 1750.
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Old April 6, 2009, 10:58 AM   #7
Pahoo
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I feel that B.L.E. pretty much covered it and I have a 1:66 twist with a 31" barrel and just for drill, confirmed by riding and measuring the rod travel.

Also, back in the day, another reason for twist or spinning the projectile was to "Spin the Devil off the ball" or so it was believed by some. That's right, !!
The Devil rode the ball and needed to be thrown off !! ....


Be Safe !!!

Last edited by Pahoo; April 6, 2009 at 02:40 PM. Reason: spelin
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Old April 7, 2009, 12:18 AM   #8
arcticap
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I remember reading how fast twist rifling by the early barrel makers preceeded the invention of the conical bullets which require it for stabilzation by many decades. Logic would make it seem that it would have been the other way around, that the conical bullet would have been invented before the advent of fast twist rifling. But some of the earliest rifling for shooting round balls was very fast. Maybe they didn't use very tight patching if any, way back then?
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Old April 7, 2009, 12:57 AM   #9
Hawg Haggen
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Maybe they didn't use very tight patching if any, way back then?
They used patches but you're right they weren't very tight. The short starter is a relatively modern invention.
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