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Old January 7, 2009, 11:26 PM   #1
straightshoooter
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barrel length

i understand .22 LR amunition generally uses faster burning powder and i read the optimum barrel length is 16", any lenth past that is friction. i (want) to use my ss 22" barrel in building a target rifle, am i wasting my time?
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Old January 7, 2009, 11:50 PM   #2
joneb
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Quote:
optimum barrel length is 16"
It's better for accuracy to err longer than short, in my opinion.
The type of action makes a difference as does the multitude of .22 ammo. I would guess 16-19" for semi-auto and 19.5-23" for bolt action would be in the ballpark.
I would look here;http://www.rimfirecentral.com/forums/index.phpfor more info
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Old January 7, 2009, 11:52 PM   #3
Bud Helms
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Not necessarily, since you are after a target rifle. Accuracy doesn't necessarily follow velocity.

Quote:
... i read the optimum barrel length is 16", any lenth past that is friction.
Not quite true. The friction is there all the way down the barrel. Pressure behind the bullet overcomes that friction. There is a point at which the bullet velocity is maximum. After that, the pressure drops off, but it does it over some barrel distance, not instantaneously. So the bullet will begin to slow down, but it would have to be long barrel to capture a high velocity .22LR bullet. I don't know how long a barrel that would be.
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Old January 7, 2009, 11:55 PM   #4
Rich Miranda
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I am no expert but, as I tend to do, will offer my opinion anyway

While there may be a certain 'optimal' barrel length, I doubt the additional length will be a problem. If you lose any velocity at all, it would be minimal. You might also gain accuracy because of the extra length.
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Old January 9, 2009, 06:33 AM   #5
Nail Shooter
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I read about a 22LR velocity test (6-8yrs ago) where somebody took a long bbl bolt gun and began to saw it off and re-crown in 1" increments, IIRC. Velocity increased going shorter until the test gun reached 16" of bbl length. They theorized that frictional losses slowed the bullet past 16".

Under 16" the velocity began to get slower with the theory that gas did not have enough time to work on the bullet or all of the powder did not burn, etc.

Interesting test. I read this a long time ago and think that I remember velocity was the only consideration. I suppose a different bbl or cartridge could result in slightly different results. I'd like to read that one again, but not sure "where I was" on the net when I came across it--maybe rimfirecentral?

Not sure that tuning a gun for max velocity has anything to do with how accurate the particular gun would be however.

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Old January 9, 2009, 06:49 AM   #6
B.L.E.
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I believe that long barrels are an accuracy advantage if you are using open sights. If you are using a scope, you may be better off with the shorter barrel because short barrels tend to be stiffer.
Where I come from, there are several shooting clubs that have rimfire matches shot from a standing crossticks position at 200 yards and open sights must be used. Some of these people shoot custom long barreled rifles that have the last part of the barrel counterbored so the working barrel is only about 16 inches long but the false barrel past that point gives them a long sight radius.
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Old January 9, 2009, 07:16 AM   #7
Bud Helms
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I remember that test.

Quote:
They theorized that frictional losses slowed the bullet past 16".
Of course, frictional losses slowed the bullet. Friction is always trying to slow down/stop the bullet. But how much pressure is employed to overcome that pressure is what results in bullet velocity.

'Not trying to be argumentive, but the point here is even though straightshoooter asked about barrel length, he is wanting to build a target rifle:
Quote:
i (want) to use my ss 22" barrel in building a target rifle, am i wasting my time?
The plain answer is, no, you are not wasting your time. Take a look at some bench rest/target .22 LR rifles for sale on the internet.

The Norinco EM-332 has a 20 inch barrel.

Walther has made .22 LR rifles with 26 inch barrels.

I haven't checked Hammerli.

Target shooting is all about accuracy. Velocity is unimportant if accuracy is attained. After some internet "research", 22-26 inch barrels for .22LR target builds are not that uncommon. And they will still kill a rabbit or squirrel.

18-20 inch barrels are very common. 22 inches should not be a problem in at all.
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Old January 9, 2009, 08:04 AM   #8
B.L.E.
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Most .22 lr ammo is already at 90% of its ultimate velocity before it has traveled the length of a pistol barrel. I would suppose that the powder is completely burned up before the bullet even travels a couple of inches and the remaining pressure continues to accelerate the bullet. At 15 or 16 inches, the pressure is so low that the bullet no longer accelerates and the remaining barrel just guides the bullet to the target.

The same thing applies to other pistol caliber rifles. I shot some of my .38 special handloads over a chronograph and the Ruger Vaquero revolver with a 5.5 inch barrel was only about 100 fps slower than the same ammo shot out of my Marlin lever action rifle with a 24 (IIRC) inch barrel.
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Old January 9, 2009, 08:17 AM   #9
blume357
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throwing aside the advantage of a long barrel if using Iron sights...

I've always leaned toward shorter is better... if only because I read it in the ultimate 10/22 by... I think he really liked something under 16", more like 10.5....but then again I may be wrong....

I will say this because this is what I've relearned after putting a new target barrel on my customized 10/22.... brand and type of ammo will make all the difference in the world. At this point Federal Game shot will shoot 3/4" at 50 yards in this rifle... while bulk stuff and 2 others do around 2-3".... same shooter... same rifle... same day..
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Old January 9, 2009, 09:44 AM   #10
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Just a couple of data points

I've a BRNO #4 with a 27" bbl and a CZ with a 28.5" bbl. With Remington subsonic either will shoot a one inch group at 100m.

If velocity were important, you would not be shooting a .22lr. Consistency is what you must have. Without any evidence to back up my thought on the matter, I believe that a very long barrel may help to minimise variations in velocity that we see with inexpensive .22lr. Minimising those variations should help accuracy.

All of that is worth what you paid to read it.
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Old January 10, 2009, 04:44 AM   #11
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also to consider

ok, fine, past a certain length the powder is all burned and friction is "slowing down" the bullet. SO WHAT? The loss is basically insignificant, a tiny fraction of the bullets speed. Not something that can make any practical difference for any application I can imagine.

Barrel length is about sight radius (open sights), and ease of handling. Overall weight and balance plays a part too. Barrel quality is more important than length for accuracy, and stiffer shorter barrels only begin to show their merits when you start talking about bench gun level accuracy.

Bull barrels on varmint guns are about heat, with stiffness being a welcome extra. And .22RFdoesn't get that hot.

your 22" barrel is fine, if your rifle balances well with it.
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