PDA

View Full Version : 20" v 26" 308 Barrel


Benwa
October 06, 2008, 18:06
Does anyone out there know how much effect there is using a 20" barrel v's a 26" barrel.

I was looking at a used savage bolt gun in 308, it has a heavy 20" barrel and a factory folding stock, it's used but priced at $699, but I'm worried about how much effect the shorter barrel will have on the performance.

Any help would be greatful, Benwa

MAINER
October 06, 2008, 18:32
Depending on the load used, about 120fps loss in muzzle velocity. I would expect no difference in accuracy.

In general, cartridges in the 2500 to 3000fps range change approx 20fps muzzle vel per inch of barrel.

High vel/pressure rounds change more per inch and slower/lowpressure loads loose less.

No offense meant, but $700 for a used Savage? Rifles scarce in your neighborhood?

lew
October 06, 2008, 20:12
Mainer posted some good info. 20 fps./inch is a good rule of thumb.

You can get a new Savage the way you want it for less than that.

astroman2057
October 06, 2008, 20:24
I agree on price-shop around-I picked up the same rifle (Savage 10 FP LE) with a Bell and Carlson stock, Harris bipod, Nikon 4.5x14 w/rings for $800.00 in mid August. Be patient and shop-like Lew said a new one is cheaper-check out the retail pricing on the Savage website.

Regal Beagal
October 19, 2008, 20:25
Benwa,

As others have mentioned there is only about a 20 fps loss /" in velocity between the lengths. It shouldn't affect accuracy. I built up a .308 carbine off of a Interarms Mark X mauser action and added a Shilen match grade #5 heavy barrel that I cut to 20" and target crowned. Even with Winchester Super x ammo I can shoot dime size 5 round groups at 100 yrds and 200 yrds and inside a penny at 300 yrds. With my handloads I can achieve hole in hole at 100 yrds as long as I do my job otherwise they clover leaf/ overlapping. The one thing I like about the heavier barrel is that it is stiffer giving better accuracy. I also like the fact that I can usually shoot a few 5 round groups without the barrel majorly overheating and degrading accuracy. I do have Browning Abolts in 7mm mag and 300 win mag that sport 26" barrels that after 3 rounds you have to let cool down. Of course, being mag does create a good bit more heat..... Both those rifles are quite accurate.... Even with a 20" barrel my .308 does weigh more than the Abolts but it does balance quite beautifully with recoil being marginal. My Abolts are great and I use them for long range shots for deer sized game and larger but you are more likely to see me carrying my .308 on most of my hunts. It's my woods and brush carbine..... I am with the others, you can get a new Savage for less than $700.00. Personally, I don't buy new anymore and I do my best to shop for the best deal sometimes waiting until the right deal comes along. Check the auction sites to see what they are going for and if you can find an FFL in the area who will receive it and do all of the paperwork for less than $25 you can get a great deal. RB

tac-40
October 20, 2008, 03:59
Having just purchased an FN PBR with a 20" barrel instead of the 24" one, I'll let you in on my research. Basically it boils down to this: If you are going to be shooting at 600 yds or less, then a 20" barrel will suit you fine. Anything over 600 yds, go with the longer barrel. The loss of velocity due to the short barrel has an adverse effects on the long range performance of the bullet.

Will all this have any affect on you and your rifle, can't say. I know that my rifle is infinitely more accurate than I can be, so getting a longer barrel was a moot point. I chose the shorter barrel to keep the rifle shorter, lighter and handier.

hagar
October 20, 2008, 09:32
In a heavy barrel rifle, I would always get the longest barrel possible, at least 24 and preferably 26 inches. I shoot mine mostly prone off a bipod, or from the bench, and want to get the blast and noise as far away from my face as I can. The extra velocity is free, and so is the extra weight helping to steady it. Now in a hunting or carry rifle I find 22 inches to be ideal, and even 20 is fine in one with moderate recoil and blast.

If you want to buy the 20 inch version, go for it, but I would be horrified if you wanted to cut down a 26 inch barrel to 20.:uhoh:

ftierson
October 20, 2008, 13:15
Originally posted by hagar
In a heavy barrel rifle, I would always get the longest barrel possible, at least 24 and preferably 26 inches. I shoot mine mostly prone off a bipod, or from the bench, and want to get the blast and noise as far away from my face as I can. The extra velocity is free, and so is the extra weight helping to steady it. Now in a hunting or carry rifle I find 22 inches to be ideal, and even 20 is fine in one with moderate recoil and blast.

If you want to buy the 20 inch version, go for it, but I would be horrified if you wanted to cut down a 26 inch barrel to 20.:uhoh:

I agree with hagar...

Although short barrels have their place (for one example, in light, handy rifles for hunting in vegetation), it's generally better to go with longer barrels for increased velocity.

Although the general rule of thumb is about 20fps/inch loss in velocity from 24 to 20 inches in a cartridge like the 7.62x51mm, the actual loss will be somewhat greater since you can be pushing a 150gr out at around 3000fps with an optimal powder in a 26inch barrel (thus, the 30fps/inch generalization is more applicable).

Forrest

ftierson
October 20, 2008, 13:26
By the way, I should have added that accuracy is not necessarily an issue here (short vs long) if a riflescope is being used and we're not worrying about the distance between front and rear sights...

I have a friend who has a 16inch straight (no contour) barrel on a Remington 600 action in .223 Remington (he bought it, nearly new, that way). I don't have the rifle in front of me to measure right now, but the muzzle must be 1.5 inches in diameter (perhaps slightly more). Consequently, the rifle is pretty heavy. It is also one of the most accurate .223 Rem. rifles that I have ever seen or shot. Pretty minimal barrel whip, I'm guessing...:)

It's also one of the most unpleasant .223 Rem. rifles that I've ever shot, since it's still burning powder after the bullet leaves the muzzle (awful muzzle blast and fireballs).

I've never chronographed this rifle, but I have chronographed 16inch ARs compared to 20inch ones. That's why most of my ARs have 20inch (or longer) barrels...

Forrest

L Haney
October 24, 2008, 17:51
Jeez Forest, why you have to be droppin' facts and personal experience in here? :rofl: Somebody check the length of the barrels on the GAU-8 30 mm. That bitch still has a serious case of muzzle blast and flash. But it'll hit a 20" circle at 2.5 miles. Never seen one shot at paper though!

Lowell

Glock63
October 31, 2008, 20:33
you will lose about 50 - 60 fps using fed gold medal 168. If you handload, this difference can easily be made up using a slightly faster powder.