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View Full Version : is there a huge difference on longer barrels?


peter95
02-21-2011, 11:26 AM
I've talked to a few people about differences in longer and shorter barrels.
Some said that there is no difference between 20" and 24" barrels and some said that there is a huge difference between them.

I tried searching and did not find too much info on them so I thought I'd post and see what you guys thought about it.

So what are the differences between them?

siliconphreak
02-21-2011, 11:32 AM
Velocity and sight radius if your using irons. From what I recall it's a 150-200fps difference.

Nathan Krynn
02-21-2011, 11:41 AM
It matters also on the profile and caliber.

A shorter barrel is actually inherently more accurate due to barrel whip and harmonics.

Yes longer has more velocity but most if it whips then the accuracy will suffer big time.

If this is an AR barrel for .223-5.56 never bother with 24" IMHO.

Ahhnother8
02-21-2011, 11:46 AM
50+-fps per inch

Fjold
02-21-2011, 2:11 PM
Depending upon the bore size the velocity will vary anywhere from 20fps to 100fps per inch of barrel length in identical cartridges. With a high expansion ratio cartridge like a 45.70 you'll see smaller velocity per inch increases than with a cartidge like a 22.250 which has a low expansion ratio.

Stiffer barrels will whip less but if the barrel whips the same amount everytime you'll see less accuracy issues. You can make a long barrel stiffer by making it heavier walled but the penalty is weight. Individual barrel differences in uniformity of the surface, accuracy of the dimensions and the quality of the chambering can make a bigger difference than barrel stiffness.

Kalman
02-21-2011, 2:41 PM
Severly overstated. I remember reading a page where a guy chronographed like 10 different types of 308 win match ammos between a 20" and a 26" barrel and they were within 20FPS of each other, with the 20" barrel occasionally being FASTER. It's severly overstated how much longer barrels help.

mixicus
02-21-2011, 2:45 PM
From another post on the same topic:


Assuming you hand load and have a load that will take advantage of the extra barrel length, you can expect 20-30fps more per inch of barrel. So using the same load with a 52gr HPBT and doing either 3000 or 3100 fps dependent on barrel length alone, the drop will be ~37" v 34" with a drift of 29" v. 28" (10mph full value) at 400 yards. Not much difference.

As for accuracy, if you are running an optic, considering barrel length alone, the additional barrel length will not have an effect on your accuracy. Of course the same load may not be in the sweet spot for both barrels. If you were shooting iron sights (barrel mounted front sight like a Tubbs), the longer sight radius would help you use the accuracy potential of your rifle.

If you want an idea on range, just to put some number out there, you can arbitrarily set max accuracy range for the point the round drops below Mach 1. Yeah not perfect but it'll give you an idea. Using the load from above, the range is either ~575 or 600 yards. Again not much difference.

The barrel length will effect the balance and handling of the rifle.

Coded-Dude
02-21-2011, 2:52 PM
Recoil. or is there no discernible difference between 16", 22", and 30"?

Nathan Krynn
02-21-2011, 2:56 PM
On an AR recoil has to do with gas system length and not really barrel length. The longer the system the less the recoil. Lets face it though a 5.56 is a very light recoiling round. But rifle length is the lightest and that is typically a 18"+ barrel.

I am not a bolt gun expert if you are talking that.

Kalman
02-21-2011, 7:14 PM
Recoil. or is there no discernible difference between 16", 22", and 30"?

Depends on weight. A 16" Bull barrel that weighs more than a 30" slim barrel will have less recoil, but similar profiles the longer barrel will be heavier so the recoil will feel less.

Jpach
02-21-2011, 7:15 PM
I've talked to a few people about differences in longer and shorter barrels.
Some said that there is no difference between 20" and 24" barrels and some said that there is a huge difference between them.

I tried searching and did not find too much info on them so I thought I'd post and see what you guys thought about it.

So what are the differences between them?

What caliber? THATS what makes a huge difference.

nrakid88
02-21-2011, 7:26 PM
12 ga gets all its velocity in the first ten inches. I bet 458 socom is the same. .22lr is another caliber that peaks velocity wise under 16 inches.

Then 50bmg will still be accelerating at 20 inches.

Jpach is right, depends on the caliber, mixicus was right too as the load is a big factor as well.

peter95
02-21-2011, 10:15 PM
currently running a 20" barrel with .223, bolt action rifle.
Just wanted to know if there was a difference in accuracy or not, but seems like there is really much of a difference to no difference at all.