Good .308 barrel Length?

[hawk1]

Ok... so I bought a brand new (never been shot) DPMS LR308T a few weeks back. I'm planning on using it as my hunting rifle. I bought it thinking I could easily trade or sell the current 16" barrel and get a 20" barrel. But, the more I take it out and play with it, (the gun!!!) the more I'm considering just keeping it as is. So my question to the board is: At 200 yards would I be able to keep my 1" groups with a 16" barrel? Or should I just order a 20"?

What I'd really like to do is zero it in for 400 yards, but my gut is saying that's a little outside its range? Or is it?

Can someone please give me some insight into this?! I'd really like to get some quality input before I shoot it and am unable to trade or sell the barrel as NEW.

Thanks,
Hawk1

[ColoEnthusiast]

If 200 yards is on the farther end of you expected range, why not keep the 16"? You lose some velocity, but accuracy should be very close to a longer, similar profile barrel. From what I have read and seen, accuracy is not dependent on longer barrel length, but heavier profile.
Bet that is a sweet little .308 rifle!! Let us know how it does...

[Backinblackrifles]

I think more than length it is about the quality of the barrel. I would shoot it at the 400 and if it is inside 4in. than it is a great rifle if it is within 5in. it is still a good rifle and for hunting I would keep it until it is shot out. Pittsburgh police did very well in the international sniper competition with a 14in. barrel. Now personally for weight balance and so on I like an 18in. barrel but that is just me.

Long story short you will not know until you try.

[hawk1]

[quote=ColoEnthusiast;194568]If 200 yards is on the farther end of you expected range, why not keep the 16"? You lose some velocity, but accuracy should be very close to a longer, similar profile barrel. From what I have read and seen, accuracy is not dependent on longer barrel length, but heavier profile.
Bet that is a sweet little .308 rifle!! Let us know how it does...

What do you mean by heavier profile? I'm relatively new to AR style guns so I'm still learning things all the time!
Do you think, I (being a relatively decent shot) would be ok taking 400 yard shots with this gun?! I'm looking for some advice before I break in a new barrel!!!

[ColoEnthusiast]

Heavier profile is the thickness of the barrel. Thicker steel reduces harmonics and generally gives better accuracy. Other factors are involved, but it is generally true. Old school thinking was, if the barrel is short accuracy suffers. That is siimply not true. I would be happy with the 16" barrel due to the light weight and quick handling. Just personal preference.
If you can shoot 1" groups at 100 yards that is very good IMO. From that you can extrapolate that the rifle has the capability of approx 4" groups at 400 yards. To do that though, would require high powered optics and practice.
I personally like S African surplus for sighting in and plinking. I get good accuracy with it, but results vary from rifle to rifle on ammo. For top-notch accuracy though, you're going to want some premium ammo like Federal GMM, other high quality brand or handloads.
From what I understand those are great rifles. I checked one out once and it had an excellent feel. I was amazed at the weight! Very light for a .308 SA rifle..

[hawk1]

Makes sense!!! Your insight has got me thinking I will just keep what I've got and at least give it a shot! The S frican surplus ammo, where would I find that? The book says to shoot only domestic ammo and avoid stuff that is lacquered. Does it REALLY make a difference?

[Tim K]

Shorter barrels are generally more accurate than longer barrels of the same profile because they are stiffer. Velocity loss may not be much of an issue either. I read about some research LA SWAT did where they cut a barrel back 1" at a time from 24" or 26" all the way back to 16" or 18". I don't recall the specifics, but the velocity loss was so minimal that they settled on 18" length for their tactical type precision rifles.

If your current combination shoots to your satisfaction, save your money and go buy some reloading equipment. You'll be surprised how much more accuracy you can find by fine tuning a load to your individual rifle.

[spencerhenry]

sight zero at 400 yds? going to be quite high at 100 to 200yds, too high to shoot at something deer size or smaller without holding under. shooting game at 400yds with a 308, especiallly a 16" barrel is not something i would feel good about doing unless you are talking about coyotes or other varmints. 308 is a great caliber, but it is not a "flat shooter", nor is it a long range powerhouse. many studies have been done on how much performance you lose on short barrels, but a good guess is about 100fps per inch. you will certainly be down a few hundred fps from a 24". look in a reloading manual for downrange ballistics with a few hundred fps shaved off the muzzle velocity.

from my sierra manual: 165gr hpbt, max velocity from a 26" barrel is 2700 fps, just assume that with a 16" barrel you are still at 2500fps (probably less). sighted zero a 400yds, the bullet will be about 10" high at 100, 16" high at 200, and 13" high at 300. but if the muzzle velocity is say 2400fps, the mid range trajectory is 12", 18", and 15". with a velocity remaining at 400yds of under 1600 fps and energy is under 900ftlbs. i doubt any 308 caliber bullet is intended to expand at that slow a velocity.

i have shot quite a few animals at long range, and it is amazing how little power a bullet has left at 400 yds or more. a bullet capable of smashing bone at 200yds or less will sometimes glance off a bone at 400 plus.
i just shot a coyote today at 583yds. shot him 3 times at that range(missed 4 times). he was going to die, but not right away. the bullets were going too slow to expand or impart much energy on the animal. i finally got to about 200yds and finished him off.

[ColoEnthusiast]

There was a guy selling some S. African ammo awhile back for $70 per 140rd. battle pack. Click .308 (http://www.co-ar15.com/forums/showthread.php?t=21536) for his ad. It is brass with berdan priming, so not reloadable, but no worries for that rifle of yours.
Realistically, most people have no real need for extreme range shooting other than for targets and recreation. Totally preference, but IMO, I would love to have a .308 AR with either 16 or 18 inch barrel. I would put a red dot, like an Aimpoint or Eotech on it and co-witness it with flip rear sight.
Speaking of 18" barrels, HK91's are also 18" like the SWAT rifles mentioned above... Little longer than yours, but not by much.

[hawk1]

sight zero at 400 yds? going to be quite high at 100 to 200yds, too high to shoot at something deer size or smaller without holding under. shooting game at 400yds with a 308, especiallly a 16" barrel is not something i would feel good about doing unless you are talking about coyotes or other varmints. 308 is a great caliber, but it is not a "flat shooter", nor is it a long range powerhouse. many studies have been done on how much performance you lose on short barrels, but a good guess is about 100fps per inch. you will certainly be down a few hundred fps from a 24". look in a reloading manual for downrange ballistics with a few hundred fps shaved off the muzzle velocity.

from my sierra manual: 165gr hpbt, max velocity from a 26" barrel is 2700 fps, just assume that with a 16" barrel you are still at 2500fps (probably less). sighted zero a 400yds, the bullet will be about 10" high at 100, 16" high at 200, and 13" high at 300. but if the muzzle velocity is say 2400fps, the mid range trajectory is 12", 18", and 15". with a velocity remaining at 400yds of under 1600 fps and energy is under 900ftlbs. i doubt any 308 caliber bullet is intended to expand at that slow a velocity.

i have shot quite a few animals at long range, and it is amazing how little power a bullet has left at 400 yds or more. a bullet capable of smashing bone at 200yds or less will sometimes glance off a bone at 400 plus.
i just shot a coyote today at 583yds. shot him 3 times at that range(missed 4 times). he was going to die, but not right away. the bullets were going too slow to expand or impart much energy on the animal. i finally got to about 200yds and finished him off.

No this is the S#%@ I'm talking about!!! My research can't compare to good ol' fashion discussion!!!

So in your opinion, with a 16" barrel, 165gr hpbt, with a 1:10 RHtwist, what would be a good distance to sight in at?

[spencerhenry]

if i were using a 308 for hunting, it would be sighted zero at 200yds. with a 200yd zero, there is no need to aim low, or high out to about 250yds. puts you about 2.5" high at 100, about 11 low at 300. for deer or smaller animals the 308 even with short barrel velocities is plenty powerful out to 300, with proper placement it is enough for elk and moose too, though on the edge of underpowered. the key at the longer ranges is PLACEMENT.
my ar-10 is currently sighted at about 200yds, i bought it for long range coyote hunting and intend one of these days to actually use it for that. when you start to look at long range ballistics (over 500 yds), the 308 doesnt look so good. the drop of the bullet in the 500 to 600 yd range is dramatic. range estimation has got to be right on, equipment has to be top notch, and shooter skill has to be great. even with all that, a coyote size target is a very tough shot. a man size target at that range in my estimation is easy.
since i am a long range type shooter i want the most i can get out of a caliber for trajectory which is why i have a 24" barreled ar-10, and a 26" barreled bolt rifle. both shoot the same load into one ragged hole, if i really need to shoot something flatter, i will get out a different caliber.

[spencerhenry]

my 50 bmg is actually sighted zero at 800. but it only gets shot at targets over 600 yds. sometimes up to 2000yds. to hit at 100yds, i have to aim about 5 FEET low.
my point is, sight your rifle so that you dont have to think about aiming high or low in the ranges you are most likely to shoot. i used to sight my coyote rifle at 3 to 3.5" high at 100. with that zero i didnt need to hold over out to about 325 yds. unfortunately when a coyote or fox was at 100 to 150, i would occasionally shoot over. my calling skills got alot better, and now most of my shots are at 200yds and under. with my new lower zero, i rarely miss out to 300.

[ColoEnthusiast]

Good advice from spencerhenry. I was thinking a 200 yard zero would be the ideal range as well, especially for your barrel length.

[Marine24]

One option is sight in three inches high at 100 yards. With a 165 gr bullet, your maximum point blank range would run close to 300 yards.

Within that range, not a lot of dialing in your dope is needed, since you'll be within a six inch circle out to that range.

Very effective when the shooting is fast or the targets are moving.