Barrel twist and lengths?

[KBScobravert]

I am about to purchase a barrel for an AR build. I am looking at DPMS 20"-24" in .223 for a varmint/target gun. I have roughly 1000 Federal .223 match grade 69gr and some (200+/-) 75gr Honrady TAP stuff.

My question is I can never remember what twist for what weight. I don't see myself shooting anything less than 69gr through it so what twist should I run?

As far as barrel length I know that a 18" will be just as accurate with me shooting as a 24" but I am leaning towards either 20"-24". This thing will be a safe and case queen probably never seeing bush unless I go prairie dog hunting off the back of a truck so length = weight is no bid deal.

As far as DPMS barrels selection goes it is inline with my price range. I am not wanting to drop $500 for a Shillen, Noveske, etc.

Give me your thoughts and opinions.

[FRider]

I shoot those 2 bullets, albeit in reloads, in my 20in 1:9 twist barrel. Accuracy is 1/2MOA. I do get slightly better accuracy with 52gr SMK.

[CJ]

I am about to purchase a barrel for an AR build. I am looking at DPMS 20"-24" in .223 for a varmint/target gun. I have roughly 1000 Federal .223 match grade 69gr and some (200+/-) 75gr Honrady TAP stuff.

My question is I can never remember what twist for what weight. I don't see myself shooting anything less than 69gr through it so what twist should I run?

As far as barrel length I know that a 18" will be just as accurate with me shooting as a 24" but I am leaning towards either 20"-24". This thing will be a safe and case queen probably never seeing bush unless I go prairie dog hunting off the back of a truck so length = weight is no bid deal.

As far as DPMS barrels selection goes it is inline with my price range. I am not wanting to drop $500 for a Shillen, Noveske, etc.

Give me your thoughts and opinions.

My target AR is a built with a 24" Sabre Defence 1:8 410 stainless steel super bench barrel. It took me a year with different loads, but I am dialed into sub 1/4" MOA, optics limited. I think it's capable of all rounds through the same hole at 100 yards if I had the optics. At 200 yards it shoots 1/2" MOA, and at 1000 yards w/ low wind I can hit a dinner plate 7/10 times. I could probably do better if I breach loaded 90-110gr VLD's - wind is a killer on such light bullets with that kind of range. The plate is covered up by the cross hair center at that range - really need some better optics.

There is a hell of a lot to know when it comes to target AR barrels, I can vouch for that. But, maybe I can lend some insight from my experience. I decided on a 24" barrel for several reasons. This AR was built as a long range target rifle. If you plan on shooting 600+ yards you need as much velocity as you can afford. The 24" is the last weight/whip/stabilization that makes monetary sense. As for twist rates, the longer the barrel, the less twist you need in a general sense. Also, the faster the twist, the more velocity you bleed off. A 1:9 barrel 20" in length should be okay up to a 70gr, I've heard some say a 1:9 twist will stabilize a 75gr - it may prevent a flier, but it sure isn't going to be consistent as it could be with a faster twist. I personally think anything over a 69gr in a 1:9 twist is unrealistic. I can easily stabilize 77gr BTHP in my 1:8, and that's as quick of a twist as anyone would ever need. It also will fire down to a 42gr without scattering the projectiles. Now, here is something I've come to learn, which I hardly ever seen anyone else mention. There is no need for a 20"+ 1:7 twist barrel. Anything over a 75gr hornady HBPT (with the exception of the Sierra 77gr) will not fit into a standard magazine because it's OAL exceeds 2.265". So, why the hell would you want a barrel with a faster twist than 1:8 if you can't load the rounds into a magazine? Breach loading is for bolt actions, not for AR's. So, in my opinion a 1:8 24" barrel is the absolute best barrel for a long range AR-15, it can easily stabilize the largest magazine rounds made, and it doesn't suffer for excess twist which lowers velocity, and furthermore the extra length increases the velocity even further - to about as fast as a .223 can fly without exploding. On average i measure between a 100-160fps increase in velocity from a 20" barrel to my 24", and of course tighter groups 300yds+.

It's worth mentioning also that barrels over 20" benefit greatly from considerable increase in diameter. Anything over 20" with a standard bull barrel diameter will most likely lose some degree of accuracy due to barrel whip. If you do plan on purchasing a 22 or 24" barrel make sure it's a bench barrel. So, in summary I would suggest a 1:8 twist in any barrel 20" or longer, primarily because it allows you to shoot the larger weight bullets which you will want if you plan on putting your target AR to the test. Also, you might want to set aside some scrilla for a press, because you're going to need hand loads to achieve the accuracy your rifle will be capable of.

P.S. Did I mention they are long?

[KBScobravert]

My target AR is a built with a 24" Sabre Defence 1:8 410 stainless steel super bench barrel. It took me a year with different loads, but I am dialed into sub 1/4" MOA, optics limited. I think it's capable of all rounds through the same hole at 100 yards if I had the optics. At 200 yards it shoots 1/2" MOA, and at 1000 yards w/ low wind I can hit a dinner plate 7/10 times. I could probably do better if I breach loaded 90-110gr VLD's - wind is a killer on such light bullets with that kind of range. The plate is covered up by the cross hair center at that range - really need some better optics.

There is a hell of a lot to know when it comes to target AR barrels, I can vouch for that. But, maybe I can lend some insight from my experience. I decided on a 24" barrel for several reasons. This AR was built as a long range target rifle. If you plan on shooting 600+ yards you need as much velocity as you can afford. The 24" is the last weight/whip/stabilization that makes monetary sense. As for twist rates, the longer the barrel, the less twist you need in a general sense. Also, the faster the twist, the more velocity you bleed off. A 1:9 barrel 20" in length should be okay up to a 70gr, I've heard some say a 1:9 twist will stabilize a 75gr - it may prevent a flier, but it sure isn't going to be consistent as it could be with a faster twist. I personally think anything over a 69gr in a 1:9 twist is unrealistic. I can easily stabilize 77gr BTHP in my 1:8, and that's as quick of a twist as anyone would ever need. It also will fire down to a 42gr without scattering the projectiles. Now, here is something I've come to learn, which I hardly ever seen anyone else mention. There is no need for a 20"+ 1:7 twist barrel. Anything over a 75gr hornady HBPT (with the exception of the Sierra 77gr) will not fit into a standard magazine because it's OAL exceeds 2.265". So, why the hell would you want a barrel with a faster twist than 1:8 if you can't load the rounds into a magazine? Breach loading is for bolt actions, not for AR's. So, in my opinion a 1:8 24" barrel is the absolute best barrel for a long range AR-15, it can easily stabilize the largest magazine rounds made, and it doesn't suffer for excess twist which lowers velocity, and furthermore the extra length increases the velocity even further - to about as fast as a .223 can fly without exploding. On average i measure between a 100-160fps increase in velocity from a 20" barrel to my 24", and of course tighter groups 300yds+.

It's worth mentioning also that barrels over 20" benefit greatly from considerable increase in diameter. Anything over 20" with a standard bull barrel diameter will most likely lose some degree of accuracy due to barrel whip. If you do plan on purchasing a 22 or 24" barrel make sure it's a bench barrel. So, in summary I would suggest a 1:8 twist in any barrel 20" or longer, primarily because it allows you to shoot the larger weight bullets which you will want if you plan on putting your target AR to the test. Also, you might want to set aside some scrilla for a press, because you're going to need hand loads to achieve the accuracy your rifle will be capable of.

P.S. Did I mention they are long?

CJ excellent info once again as usual. Thanks. I just ordered a 24" Saber 1:8 in .223. I was hoping to gas piston this build but I can not find a kit for a .920" barrel that I like. The adams arms kit is for a .750", unless I have it opened up. For now it will have to be a DI gun.