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tanda10506
02-19-2012, 8:30 PM
As far as I have always understood, all things equal, a longer barrel will have as higher velocity (not necessarily much) and better accuracy then a shorter barrel. Not specifically with AR15's but with most rifles. So I was looking at putting a 20" upper on my complete lower. I already have 2 16" AR's and I figured I would try out a 20" for the increased accuracy. After doing some research though, it seems like the general opinion is a 14.5, 16, and 20 inch upper will all have the same accuracy (all other things equal). Is that true?

tomd1584
02-19-2012, 8:32 PM
More Velocity yes, more accurate not necessarily.

freonr22
02-19-2012, 8:41 PM
After having 5 ars, my next will be a 1/8 18"...

tanda10506
02-19-2012, 9:56 PM
And why is that?

russ69
02-19-2012, 10:09 PM
...all things equal, a longer barrel will have as higher velocity (not necessarily much) and better accuracy then a shorter barrel...

No. A short and stiff barrel has more accuracy potential than a thin longer barrel. The key point being barrel stiffness.

tanda10506
02-19-2012, 10:12 PM
I understand, that's what I meant by all things equal. It will be an HBar upper either way, made by the same company and same materials.

3GunFunShooter
02-20-2012, 2:04 PM
Longer does equal more velocity. Had a friend use PMC Bronze 55Gr in his 16" barrel and it would not make minor power factor at a major match. With my 18" it does.

pat4wd
02-20-2012, 4:07 PM
At what point do you start to lose velocity on barrel length? Once powder is burnt and pressure starts to fall? I have heard many different opinions on this.. Or I guess my Question could be what is the ideal length not too long or too short to get the most out of your rifle cartridges powder

TheHammerOfTruth
02-20-2012, 4:41 PM
No. A short and stiff barrel has more accuracy potential than a thin longer barrel. The key point being barrel stiffness.

This is partially true, but OP, dont think that you will get superior accuracy from a 10" bull barrel over a 20" barrel. Barrel length does come into play.

CIV Tactical
02-20-2012, 5:30 PM
you get more velocity out of a 20 inch barrel because your propellant gases are given more time to expand and build pressure. This in turn gets your round to its target at a faster rate which provides less time for error. In the end of the day accuracy comes down to shooting skills and understanding your firearms function.

Drivedabizness
02-20-2012, 5:51 PM
you get more velocity out of a 20 inch barrel because your propellant gases are given more time to expand and build pressure. This in turn gets your round to its target at a faster rate which provides less time for error. In the end of the day accuracy comes down to shooting skills and understanding your firearms function.

+1

Also -
Length corresponds to sight radius. The longer the sight radius (with irons) the greater the potential accuracy. Note that many target pistols or even national match AR's have an extended front sight so as to achieve that longer radius.

russ69
02-20-2012, 9:03 PM
At what point do you start to lose velocity on barrel length? Once powder is burnt and pressure starts to fall? I have heard many different opinions on this.. Or I guess my Question could be what is the ideal length not too long or too short to get the most out of your rifle cartridges powder

The 22LR is finished at 16 inches. Centerfires will still have an increase in velocity with any reasonable length barrel. Reasonable meaning any length including the longest barrel target rifles.
The perfect length is compromise of velocity and barrel weight.