#493688 - 11/14/07 06:15 PM
Re: Most accurate round...with 20" barrel?
[Re: 4onaside]
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megalomaniac
10 Point
Registered: 10/28/05
Posts: 4887
Loc: Mississippi
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All rifles will be more accurate with a shorter barrel over a longer barrel (all other things being equal).
That being said, what you are looking for is a caliber which is capable of using case capacity (ie burning the powder) in a short barrel.
All the .308 family (.243, .260, 7-08, .308) are quite accurate and are still quite efficient even with a 20" barrel. I realize that my response does not address the specific question asked by Goat-roper, but they are more "efficient" in a 22", 24" or most of all a 26" barrel. For every inch that you chop off from 26", you lose quite a few fps(velocity), which in turn gets back to the efficiency of a round, doesn't it?
Ahh, that's the rub...
ALL cartridges will lose velocity as you shorten the barrel. BUT, some cartridges will experience a disproportionate drop in velocity with barrel shortening compared to other cartridges. Thus the 'efficiency' concept. The .308 family will retain a larger percentage of its original velocity when chopped from 26 to 20 inches over much larger cases. Although the larger cases will still be travelling faster than the 308 at 20", they will have lost disproportionately more velocity.
The concept of lengthening the barrel is similar as well. Most cartridges have an optimum barrel length, and going beyond that the gains in fps/inch of barrel begin to diminsh significantly. Most hunting cartridges operate at most efficient (velocity versus the inconvenience and decreased accuracy of a longer barrel) lengths of 24-26". Exceptions are the ultramags which operate at maximum efficiency of barrel lengths of 28-30"
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#493705 - 11/14/07 06:23 PM
Re: Most accurate round...with 20" barrel?
[Re: megalomaniac]
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megalomaniac
10 Point
Registered: 10/28/05
Posts: 4887
Loc: Mississippi
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Here's some real numbers, although different barrels:
15" encore pistol 7mm-08 140gr BT, 47g re 19......2500 fps
22" rem 700 7mm-08 140gr BT, 47g re 19......2725 fps
I forget where I saw it, but there's a chart on the web where a fellow actually started with a 26" barrel and cut it off at 2" increments and recorded the velocity after each shortening job. If I recall, he ended up with around 25 fps/inch decrease in velocity with that particular cartridge.
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#493843 - 11/14/07 07:26 PM
Re: Most accurate round...with 20" barrel?
[Re: megalomaniac]
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smstone22
16 Point
Registered: 01/11/04
Posts: 16261
Loc: Allardt, TN
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Why do long range shooters use very long barrels?
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#493855 - 11/14/07 07:34 PM
Re: Most accurate round...with 20" barrel?
[Re: smstone22]
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TiminTN
12 Point
Registered: 06/18/00
Posts: 6264
Loc: Memphis,Tennessee U.S.A.
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Yeah, why?
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#493902 - 11/14/07 07:59 PM
Re: Most accurate round...with 20" barrel?
[Re: smstone22]
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megalomaniac
10 Point
Registered: 10/28/05
Posts: 4887
Loc: Mississippi
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Why do long range shooters use very long barrels?
??? For the extra velocity, of course.
But they don't build 28" ers on a #2 contour.
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#493925 - 11/14/07 08:08 PM
Re: Most accurate round...with 20" barrel?
[Re: megalomaniac]
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smstone22
16 Point
Registered: 01/11/04
Posts: 16261
Loc: Allardt, TN
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Well I may have learned something.
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#493947 - 11/14/07 08:20 PM
Re: Most accurate round...with 20" barrel?
[Re: TiminTN]
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TAS
6 Point
Registered: 08/20/07
Posts: 563
Loc: Hickman County
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LOL
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#494337 - 11/15/07 06:29 AM
Re: Most accurate round...with 20" barrel?
[Re: megalomaniac]
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Whelen Man
TnDeer Old Timer
8 Point
Registered: 03/12/99
Posts: 2327
Loc: Athens, TN, USA
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All rifles will be more accurate with a shorter barrel over a longer barrel (all other things being equal).
That being said, what you are looking for is a caliber which is capable of using case capacity (ie burning the powder) in a short barrel.
All the .308 family (.243, .260, 7-08, .308) are quite accurate and are still quite efficient even with a 20" barrel.
Don't forget my 358 Winchester now! It's my favorite hunting rifle in a 20 inch barrel. It's a good combination of size, range, and efficiency in a handy barrel length. I would limit it's use to 300 yards though. In the shorter barrels the less the expansion ratio the greater the efficiency . A lot of powder needs a lot of barrel and vice versa. I vote for the 308 or 358 Winchester.
(Of course now I'm leaving out the 338 Federal which should be equally good with the right bullets.)
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#494447 - 11/15/07 08:27 AM
Re: Most accurate round...with 20" barrel?
[Re: Whelen Man]
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renegade50
16 Point
Registered: 02/02/07
Posts: 14240
Loc: tn
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here is a pretty interesting and kinda funny story ( my shoulder paid the price) when i was up home in maine recruiting (longest 3 yrs of my carrear) i went to a race rifle 100yd( target rifles ) match, these things had huge power scopes shooting br and ppc calibers and fancy thick stiff bull barrels.well i showed up with my model70 classic sporter ot 6 with my 2.5x8 leupy and my good factory 165 gr hunting ammo, its tricked out and shoots 3 rds 1/2 in moa if i do my part, i shoot with cold clean barrel and let it cool down and boresnake trying to match a cold clean hunting barrel each shot is how i shoot it all the time.the match was a possible 300 score you had 7 targets one of which was for a 10 minute sightin the other 6 targets you had 10 minutes apeice to put 5 rds on it and then what ever time break was between rotations to get your barrel cleaned and back on line. it was the complete setup wind flags the little windmills you know all the stuff... i shot 11 x's that day and scored a total of 242 out of 300 keeping my scope on 2.5 power and actually finished 19 out of 25 shooters, after the match the free shoot started happening i shot a guys 6mm br or ppc rifle on 24 power and shot 5 x's with his gun in a row on one target due to that bull barrel purely i think it was a fun day but after firing 33 ot6 hunting rounds (1st 3 where intial sighters)my shoulder was toast... never have had the inclination to ever shoot something like that again . i know i got a highly accurate hunting rifle with a nice cold clean hunting barrel but as far as its repeatablity in a match like that over an extended amount of firing it aint got what it takes cause of it being a sporter barrel. i just cringe at the memory of how my shoulder felt that evening and the next 2 days still hahahaaaaaa!!!!!
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#495501 - 11/15/07 08:50 PM
Re: Most accurate round...with 20" barrel?
[Re: renegade50]
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DaveTN
4 Point
Registered: 05/04/06
Posts: 354
Loc: Middle Tennessee
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For people who use open sights longer barrels are more accurate because they have a longer sight radius.
The long and short of whether "the barrel” is more accurate is simply physics and metallurgy. The more stable barrel will be more accurate regardless of its length.
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