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#1
07-30-2007, 05:08 AM
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velocity vs barrel length
Quick question (maybe dumb too), does the length of the barrel effect the velocity of a bullet?
For example if I look at a ballistic chart for a 243 and it says it has a velocity of 3200fps using a 24" barrel, should I expect more or less velocity with a 26" barrel? thanks 
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#2
07-30-2007, 07:49 AM
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The short answer is yes, you will see a little more velocity out of a longer barrel. But not enough to see any difference in the field.
gd
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We hunt, not only because we want to, but because at our basest levels we must.
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#3
07-30-2007, 09:49 AM
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As gd said the answer is yes. See anything more in the field. . . . welll it depends on what we are talking about. It is my understanding that you see a noticible change in accuracy and velocity when you go from a 20" barrel 270 or 308 to a 28" barrel like on the Thompson pro-hunter (Which is one of the reasons why I want one so bad I can taste it. . . . . mmmm gun oil)
my 2 cents (with a little sixteenth hand info thrown in) GoodOlBoy
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(Moderator - Gear & Gadgets, Cowboy Action, SouthWest Regional, Small Game) GoodOlBoy@huntchat.com For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. - John 3:16 KJV Then I commended mirth, because a man hath no better thing under the sun, than to eat, and to drink, and to be merry: for that shall abide with him of his labour the days of his life, which God giveth him under the sun. - Ecclesiastes 8:15 KJV "The gun has been called the great equalizer, meaning that a small person with a gun is equal to a large person, but it is a great equalizer in another way, too. It insures that the people are the equal of their government whenever that government forgets that it is servant and not master of the governed." - 40th President of the United States Ronald Reagan 1911-2004
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#4
07-30-2007, 12:17 PM
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thanks for the answer. it is what i suspect it to be
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#5
07-30-2007, 04:39 PM
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Yes is not always the right answer. It depends on the burn rate of the powder and the amount of powder your burning. The easiest example is a .22 sub-sonic rimfire. They have such a small amount of powder that they are faster for pistol lenth barrels then for a 26 in. rifle barrel. This also can happen when useing small amounts of a fast burning powder in a centerfire rifle. The guys that are useing the 30 in. barrel to get more velosity are paying for it because they have to use very large amount of a slow burning powder to get any gain. So while yes is usually excepted as the answer it is not always true, by with most factory loads and barrel lenths it holds.
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Catfish
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#6
07-31-2007, 03:13 PM
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Well Feathermax, you have heard the long and the short of it. The short answer is yes - but only to a point, depending on the load. The long answer is once that point is reached, a longer barrel may even slow velocity slightly. Now, don't think about asking which is more accurate.
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#7
07-31-2007, 11:23 PM
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dang, that was going to be my next question. Just kidding.
I'm not much of a rifle guy, I do mostly archery. In archery, the same draw weight, same arrow will have different velocity depending upon draw length. In comparison: Arrow weight compares to bullet weight. Draw weight compares to caliber/powder. Draw length compares to barrel length. So in archery the clear and only answer would be yes. It seemed to me that the longer the barrel the longer it would be under pressure achieving more velocity. But hey, that's why I ask you guys who know what your talking about, cause I don't. Last edited by Rustywreck; 07-31-2007 at 11:30 PM.
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#9
08-01-2007, 11:27 AM
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Feather,
There is a big difference between your bow and a rifle. As long as you have some arrow lenth left the string is putting presure on the arrow at a rate higher than that of the drag. BUT, in a rifle with a long barrel and a lite charge of fast burning powder the powder will be spent in the first few inches on the barrel and the presure will fall off fast and befor the bullet gets to the end of the barrel the drag of the bullet against the barrel will be greater the the force of the presure pushing the bullet. Now if that don`t make it clear as mud I give up. 
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Catfish
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#11
09-27-2007, 02:10 AM
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I can’t recall exactly what publication had it? ??? American Gunsmith or Gun Test Magazine possibly ???? As I remember it the discussion was with the 17 HMR when it was 1st released. The discussion centered around the best barrel length. Seems they cut one and re-crowned it. They tested it for speed and accuracy then they started cutting it down shorter and shorter. Seems like the answer was surprising like the speed increased as they cut down to 17 inches and the accuracy didn’t change. After 16(?) inches the speed started to slowly drop off. I remember I had to read it one word at a time to make sure I understood what I was reading.
The data confused the author also and they repeated it on another caliber 308? 30-06? or 270 ??? don’t remember,,, but got similar results. Seems like 18 to 20 inches would be all the longer you would want to be. Many factors effect accuracy. It has been my amateur opinion and observation that shorter barrels seem to be more tolerant to varying loads and types of ammunition just as heavy barrels seem to be. Shorter or stiffer barrels have less harmonic whip,,, I guess. Thats just my opinion and I don’t know jack,,,, or jill. 
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