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Discussion Starter #1
I thought a PSA upper with an 18" SS barrel with Wylde chamber might achieve good enough accuracy for a PD hunt coming up in June. The first one I received was achieving only 5-6 MOA with Lake City 55gr and 3-4 MOA with Fiocchi 50gr polymer tip extrema ammo. So I returned it and PSA happily swapped barrels without any questions.

Now however it is achieving possibly 3-4 MOA with LC 55gr, and about 2-3 MOA with the Fiocchi. It is a 1:7 twist and I have not tried heavier ammo, but it is pretty obvious this is not an ideal barrel for varmint hunting.

I'm ready to cut my losses and get a great barrel for this setup because the trip is coming up in June, and honestly I don't get to the range enough to play around with this too much. What barrels can anyone here recommend? I've been considering:

  1. Shilen 223 Match S/S Heavy 24" Varmint 1:12 twist 6 grooves
  2. Bartlein Wylde chamber S/S 22" (also available in 20, 24, 26") Varmint 1:7.7 Twist 4 Groove

These are just the first I've come across in my research. Price for those is about the same. I would of course get a matched bolt to go with them. Any other good options for consideration? I am not afraid to spend money if I think it is worth it.

Thanks!
 

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I've been very happy with my Krieger/Wylde heavy bbl 7.7 twist. I took a recommendation from my brother's success with the same bbl (only shorter) and both of us are shooting sub 1/2 moa center to center! Couldn't be happier!

.
 

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The GI or NATO 55gr FMJ ammo is only spec'd for 3 moa. You need to test the barrel with some good commercial bullets, like Sierra 52gr SMK or Hornady 50 or 55gr VMAX. That will usually cut group size in half or less. The bullets make all the difference, especially if you use a scope and it is >9x or >10x power.
 

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I had a Bushmaster chrome lined M-4 that would shoot 3/4 MOA with 55 grain soft points, cannot remember the brand.

The problem with a carbine length AR is the chamber size in some cheaper made barrels. Most are over gassed with the impingement system because of the short gas tube. The cartridge is still up in case expansion when the gun starts to unlock and the chamber has to be Nato or larger for reliability.

Some Barrel people like Green Mt and others have figured out the compromise and tend to be more accurate.

I think If I were all in AR for predator hunting I would go with the full-size rifle and have a barrel chambered for 223 exclusives.

I know there is not much difference in 223 and 556 but we are talking not just chambers but how much throating etc.
 

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One of our gurus on the board is "was skruske" from Michigan. Years ago I built an AR and wanted a barrel that was not top-competition grade, but good quality. He pointed me to White Oak Armament and I found what I wanted. Honestly I don't remember what kind of accuracy I achieved. I checked to make sure White Oak is still in business and indeed they are. They have a broad range of high quality barrels, including some built from Krieger blanks.

As someone else mentioned, the barrel is only part of the equation, but I sense you already know that.
 

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One thing I've also noticed about PSA barrels... They take a bit of shooting to settle down. I've seen many that don't shoot that well, but after shooting them for awhile they settle into nice groups for a factory barrel.
Do some plinking with it with the ball ammo, cleaning it often. Then after you've shot some thru it, clean it again and shoot some ammo of known quality thru it for groups.
My first PSA barrel surprised me with the amount of tiny burrs that came out on the patch after shooting it. Once I had plinked around a bit with it, broke it in some, it settled into nice groups with the first load I tried.

Steven
 

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Discussion Starter #7
Thanks so much for all the replies.

The GI or NATO 55gr FMJ ammo is only spec'd for 3 moa. You need to test the barrel with some good commercial bullets, like Sierra 52gr SMK or Hornady 50 or 55gr VMAX. That will usually cut group size in half or less. The bullets make all the difference, especially if you use a scope and it is >9x or >10x power.
I tested with a variety, counting on the higher quality stuff tightening up more than the bulk stuff. The bulk stuff was Lake City 55gr 5.56 and some Wolf Gold, and those were outrageously bad, like 5-6MOA. But there was some Fiocchi 50gr VMAX that is shooting very well from a friend's rifle, and some PMC X-Tac, and both were getting about 2-3MOA at best. I transferred the scope to a known-good Rem700 308 to eliminate the optic as a cause and, predictably, was shooting sub-MOA.

I had a Bushmaster chrome lined M-4 that would shoot 3/4 MOA with 55 grain soft points, cannot remember the brand.

The problem with a carbine length AR is the chamber size in some cheaper made barrels. Most are over gassed with the impingement system because of the short gas tube. The cartridge is still up in case expansion when the gun starts to unlock and the chamber has to be Nato or larger for reliability.

Some Barrel people like Green Mt and others have figured out the compromise and tend to be more accurate.

I think If I were all in AR for predator hunting I would go with the full-size rifle and have a barrel chambered for 223 exclusives.

I know there is not much difference in 223 and 556 but we are talking not just chambers but how much throating etc.
I am leaning toward a Bartlein, and spoke with them about chambers and said there should be no problem feeding 556 into their 223 match chamber. I will be going with a rifle-length gas system.

I've been very happy with my Krieger/Wylde heavy bbl 7.7 twist. I took a recommendation from my brother's success with the same bbl (only shorter) and both of us are shooting sub 1/2 moa center to center! Couldn't be happier!

.
The Bartlein I am looking at has a 1:7.7 twist; will there be any issues getting accuracy from 50-55gr v-max ammo from this twist?

One thing I've also noticed about PSA barrels... They take a bit of shooting to settle down. I've seen many that don't shoot that well, but after shooting them for awhile they settle into nice groups for a factory barrel.
Do some plinking with it with the ball ammo, cleaning it often. Then after you've shot some thru it, clean it again and shoot some ammo of known quality thru it for groups.
My first PSA barrel surprised me with the amount of tiny burrs that came out on the patch after shooting it. Once I had plinked around a bit with it, broke it in some, it settled into nice groups with the first load I tried.

Steven
That is something I had not considered. The trip is still 5 months out; I may make a last ditch effort to put a few hundred rounds through it and clean thoroughly (I use Dewey exclusively) before opting for a custom barrel.
 

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I bought a Kreiger for my Premium build. Once I got the gas block issue fixed it is shooting 3/8th groups. I am just loving it. 12 twist for the lighter 50g bullets.
 

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Discussion Starter #9
I bought a Kreiger for my Premium build. Once I got the gas block issue fixed it is shooting 3/8th groups. I am just loving it. 12 twist for the lighter 50g bullets.
I've been wondering about this. The Bartlein is only available in 7 and 7.7 twists while the Shilen and Krieger are available in 12. When I spoke with Compass Lake Engineering (Bartlein) they said 7.7 should be fine with 50 and 55gr bullets. But it seems from everything else I've read that 12 would be the way to go.
 

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I agree with 1/12 for light bullets! I swear by them for anything 60 grains and lighter. My first AR (in 83) was a Colt with a chrome lined 1/12. It had the carry handle, but back then I could shoot peep sights well and would shoot 5/8" groups consistantly. Heavier than that and they would group erratically.

Steven
 

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Discussion Starter #11
It just occurred to me today something that I did that may have contributed to my problems. First thing I did with the Wylde upper was swap out the BCG with one I prefer from a different rifle. However I should have kept the bolt that came with the Wylde upper and swapped out only the carrier. Potentially the headspaces are different and that could have contributed to the problem. Still, if accuracy doesn't improve after a couple hundred rounds and a few thorough cleanings, I'll be looking to a custom barrel.
 

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I have both bolt actions and ARs in 223/5.56 with barrels from 16 inches to 26 inches in length. They are both 1:9 and 1:12 twists, but don't have any in 1:7 (yet). The 1:9's will shoot anything from 40gr to 69gr bullets, typically 0.40MOA for 5 shots at 100yds. I have 1:12s that will shoot 63 and 64gr SPs, but will not stabilize the 69gr SMK, let anything longer/heavier. My longest PD .223 kill has been 481yds (with a 40gr NBT) and a 1:9.

What else do you want to use the AR for after the PD shoot?

Have you done a barrel break-in on your rifle? The classic shoot/clean and repeat process does wonders to break-in a barrel fairly quickly. You might try that also before changing barrels.
 

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Discussion Starter #13
I have both bolt actions and ARs in 223/5.56 with barrels from 16 inches to 26 inches in length. They are both 1:9 and 1:12 twists, but don't have any in 1:7 (yet). The 1:9's will shoot anything from 40gr to 69gr bullets, typically 0.40MOA for 5 shots at 100yds. I have 1:12s that will shoot 63 and 64gr SPs, but will not stabilize the 69gr SMK, let anything longer/heavier. My longest PD .223 kill has been 481yds (with a 40gr NBT) and a 1:9.

What else do you want to use the AR for after the PD shoot?

Have you done a barrel break-in on your rifle? The classic shoot/clean and repeat process does wonders to break-in a barrel fairly quickly. You might try that also before changing barrels.
I'm definitely going to try more break-in before I change barrels. Most of the barrel options I am looking at right now go from 1:7 to 1:7.7 to 1:8 straight to 1:12. Not seeing a lot of options in the middle. I would probably leave this as a dedicated varmint upper, so I am leaning toward 1:12.
 

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At issue: "Over stabilization"

I've been wondering about this. The Bartlein is only available in 7 and 7.7 twists while the Shilen and Krieger are available in 12. When I spoke with Compass Lake Engineering (Bartlein) they said 7.7 should be fine with 50 and 55gr bullets. But it seems from everything else I've read that 12 would be the way to go.
At issue is (so-called) over stabilization (from various benchrest periodicals - authors known). Ideally, the bullet axis remains in line with the line of flight*. IIRC, it was an article (or was it a post?) by Walt Berger who said (in response to ideal twist rate question) that the ideal twist rate is that which just stabilizes the bullet. And, apparently so. Otherwise why such variation in twist rates, e.g., twist rate calculators (offered on-line by many bullet manufactures).

Minimum twist rate varies by bullet shape, construction, caliber, and muzzle velocity. Round nose bullets require less spin than do spire point or VLD (read: very tapered) bullets.

Can light (e.g., 50gn 223 cal round) bullets shoot well in (say) a 8" twist bbl when a 12" twist is all that is necessary? The answer is "it depends..."

Without getting into all the science of ballistics, e.g., precession, Coriolis effect, etc., the immediate (primary) forces acting on the bullet angle of flight are gravity (as a function of time), the tendency of a pointed projectile to follow the flight path (think of a thrown football), and the gyroscopic effect trying to keep the axis of the bullet in line with that of the barrel.

At "short range", the time of flight is small and so the angle of flight due to gravity is small enough that the (arrow-like) tendency to follow the line of flight mostly overwhelms the gyroscopic "attempt" to maintain the initial (barrel axis) line of flight. As result, bullets spun much faster than necessary for stabilization can be reasonably accurate at short range where time of flight and gravity have had minimal chance to affect the initial spin axis angle. But, that all changes as time of flight (i.e., longer ranges) increases.

The bottom line is: "just enough" spin to prevent tumbling, yet allow the bullet to point into the wind (angle of attack) is best. For shorter bullets, that means less spin is best, whereas a longer bullet from the same barrel might not be stabilized and end up tumbling, evident by erratic POI and eventually "key-holing".

(I used to have a really nice graphic that explained the phenomenon very well, but alas it got lost in that Photobucket fiasco a couple years ago. It showed how the over spun bullet holding its initial angle of attack, in spite of the gravitational affect on trajectory. Air pressure pressing on the side of the bullet instead of the point deflecting the bullet path, deflection made even worse by the gyroscopic precession pointing the bullet at right angles to the direction of the force applied. The combination ads to the total error in the point of impact - especially as range increases.)
 

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I doubt an accuracy issue, I'm thinking wrong bullet weight for the twist rate. Bartlein can claim all they want but I've never seen a 1:7" twist ever shoot 55gr bullets at varmint hunting accuracy. Like everything else, accuracy means different things to different people but I've never seen that combo work at sub 1" groups at 100yds. Very few 1:8" will work that combo together either. I'm assuming you don't handload and are looking for factory ammo to cure the problem. I'd be looking at 62gr bullets in factory ammo. Might find out it goes to a near one hole shooter. I'd certainly try that LONG before spending more bucks on a barrel that's going to do the same thing.

Think long before going to the 12" twist. While it works great at light bullets, that about all it will shoot. I'd be more likely to have a 1:10" twist barrel and I have a 223 in a 700 varminter 1:10". Handles anything from 35gr to 62gr ammo at varmint accuracy. Won't be many 12" twist barrels handle that wide of bullet weight choice.
 

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Discussion Starter #16
Thanks to all in this group for the wealth of information!

I have on order from Compass Lake Engineering a 24" Douglas varmint barrel, 6-groove (4 was unavailable) 1:10 twist. Including a matched bolt. When it came to choosing barrel brand, turnaround time was a consideration (trip is in June). I think this barrel should do nicely for what I need.
 
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