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11-23-2009, 11:38 AM
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Barrel length - How long is too long?
Thinking can be dangerous, but I've been doing it again.
It would seem to me that most rifles have shorter barrels due to weight. Shorter barrels are generally blamed for less accuracy, but 20 - 22" seems to be a good compromise.
Question 1. Is a shorter barrel less accurate due to ballistics, or because of the shorter sight radius?
Question 2. What would be the optimum barrel length for accuracy, weight not withstanding?
Question 3. At what point would a longer barrel begin to negatively effect ballistics (velocity, trajectory, etc.)?
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11-23-2009, 11:44 AM
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Alot would depend on caliber,the thickness of the barrel,and the shooter.
Ken
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11-23-2009, 11:53 AM
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Don't forget, that it has really been since WW2 that barrels have gotten this short.
Winchester used to market 1894's with barrels up to 30"-32" on their rifles. The 30"+ rifle barrel was not very common, but 24" and 26" were much more common.
As for shotguns...
Many fellers up my way swear by 36" barreled guns from various manufacturers. Besides the Marlin Goose Gun, the Stevens single shots, the Ithaca single shot, Model 12's in 32" and others I can't think of right off...the longest "production" barrel I can think of was on a Marlin 120 with a 40" factory barrel!!! A couple are for sale on the auction sites right now. I had a buddy with one, and he won a bunch of card shoots with it- that's how I remember it.
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11-23-2009, 01:45 PM
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It all depends.........
Lets look at a simple case the 22LR, maximum velocity is achieved somewhere between 16 and 17 after that friction causes the bullet to slow. So in a target rifle 16-17 would be the optimum length for velocity.
With iron sights longer barrels give you more sight radius and in .22lr are quite common. In addition there is a theory that the effect of the exiting gasses is reduced in a longer barrel (26-28).
Shorter barrels are quite often as or more accurate than the long barrels and this gets into barrel stiffness and harmonics.
Progress the development of smokeless powders and in the mensuration of pressures and velocities has resulted in the ability to achieve targeted velocities in short barrels.
In centerfire rifles, the 20-22 barrel may be a sort of circular thing. Ammunition makers assume that you will have a barrel in this range & so design their ammunition for the length, rifle makers know that ammunition makers design for barrels this length, so they, and ...........you get the idea.
Reloaders more or less go along with this whole scheme caught in the same circular track.
Probably the exception is the benchrest and long range target shooters, but they are operating on what works for others which may be another circular trap.
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11-23-2009, 02:04 PM
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there are also other factors involved in this formula, becides just the barrel lenght, such as twist rate, type of rifleing, powder burn, ect.
(the military changed the bullet weight and charge on there 556 ammo when they changed to the shorter barreled m4 versus the m16s of my day) the m4s where not as acurate untill they changed the formula
powder burn rate a slow burning powder needs more barrel than a shorter burning variety, i have an old marlin model 1889 in 38-40 that has a 26" barrel that i can keep a #10 ( 1 gallon) can rolling with off hand at 100 yards, with open sights, the slow burning powder with the heavy ballard rifleing serve's to stabelize the old slow moving round. and the ky long rifles of there day where just that for that purpose.
there are 14-16 barrels today that are super accurate when shot with there designed loads,
this 17l glock was a very accurate pistol, out of the box, and with the 16inch barrel that is on it now, with the right ammo it is a serious contender that i use as my long gun in our local 3 gun matches
http://i269.photobucket.com/albums/j...g?t=1258999228
Last edited by ky wonder; 11-23-2009 at 02:07 PM.
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11-23-2009, 07:25 PM
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How long is too long?
If you're 20 yards away and the entry holes look to be made point-blank: you may need another foot or so
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11-23-2009, 07:59 PM
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I have a Hart .54 cal. custom flintlock with a 42" Douglas BBL. THATS "too long."
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11-23-2009, 08:34 PM
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How long is too long??
When the bullet exits the barrel with a "pop" that sounds like a cork being pulled out of a bottle.
It means that the powder burn is long used up and the bullet is pulling a vacuum from forward momentum.
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11-23-2009, 09:39 PM
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Some "magnum" cartridges with large case capacity relative to bore size --- the Weatherby's typifying the example --- may require a longer barrel to allow complete combustion of all the powder, but barrel length beyond the point of pressure peak in any cartridge just adds deleterious friction. Generally, shorter bbls are more likely to achieve superior accuracy because of greater "stiffness" and diminished complications of harmonics, as stated. This of course ignores sight radius as an inherent accuracy factor, which it really isn't, it's an aiming issue... I guess in theory you could concoct an example of a case where rate of rifling twist was so slow that a too short bbl would be inadequate to impart sufficient gyroscopic stability to the projectile, but as a practical matter, the "Goldilocks" length is just at the peak pressure point for the load in question.
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11-23-2009, 10:22 PM
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As mentioned above, stiffness and barrel harmonics have a lot to do with rifle accuracy.
Optics negate the long barrel advantage as to sight radius. So you are back to finding the sweet spot for accuracy for a given round, bullet weight, and powder.
You could spend a career researching this subject.
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11-24-2009, 11:35 AM
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Quote:
Originally Posted by m1gunner
You could spend a career researching this subject.
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I've only got half a career left.
Thanks for the info, everyone. I'm starting to understand better. It looks like, in the search for the perfect rifle, I need to find a quality rifle that I shoot well, then work up the optimum hand load.
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11-24-2009, 11:46 AM
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Quote:
Originally Posted by truckemup97
I've only got half a career left.
Thanks for the info, everyone. I'm starting to understand better. It looks like, in the search for the perfect rifle, I need to find a quality rifle that I shoot well, then work up the optimum hand load.
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Since you intend to handload, a consideration in barrel length is the type of powder and the expansion ratio of the cartridge.
For example, if you want to shoot OK deer and want a short light rifle, you can shoot a 7mm-08 in a 20" barrel with a medium powder like 4064 and have a handy, efficient rifle.
Take the same 20" barrel in .300mag with 4831 powder and you will have an inefficient, blasting nuisance.
In most of the overbore capacity magnums using slow powder, you need 26" barrels to get the advertised velocity. Otherwise you get mostly noise and a headache.
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11-25-2009, 11:12 PM
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"It looks like, in the search for the perfect rifle, I need to find a quality rifle that I shoot well, then work up the optimum hand load."
This changes the question from the objective to the subjective, i.e., from "shorter/longer, what's best and why", to, "what's best for the intended purpose?", which you've not described. Once you do, you will be inundated with suggestions based on the often poor personal preferences of people with an emotional and financial investment in something or another that they already own... urging you to follow their lead, ignoring unacknowledged, or unadmitted mistakes, inadequacies, etc., in favor of justifying their previous choices... Objective info: good; Subjective opinion: +/-
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