AI barrels, 1:10 or 1:12
- Thread starter remington patriot
- Start date
Both my 308 barrels are AI AW border barrels and both in 1:12. I shoot 175's and they both shoot very well. I have a 20in and 26in. I think the tighter twist would suit a heavier bullet.
1:12 is the best all around twist rate for 308's. It's ideal for everything from 150gr to 190gr and some people are even running 208's with them. 1:10 really only shines if you're planning on shooting subs.
My AIAX is a 1:10 and I wish it was a 1:12.
My AIAX is a 1:10 and I wish it was a 1:12.
I've had accuracy issues in general with 1:10 twist barrels with bullets lighter than 175. It just spins them too fast and I really like the 155 scenars so I know I can't run them in my AX. My main gripe with my AX 1:10 barrel is that it's slow as shit which is common with Bartlein barrels. 2550FPS in a 24" barrel with 168gr FGMM is just pathetic. I'm actively searching for a 1:12 lothar or border from an AW or AX swap it out with.
all kinds of incorrect here, the AX Bartleins are not slow, it's probably a LW at 2550fps unless it is hand marked, if it has a proof mark it's LW or Border. I want to see a pix of the markings.
My AX is a 20" Bartlein and it shoots 175s at 2645fps it's a 1-10. As are most of my 308s, the Gladius 1-10, hammer goes 2605fps. The 1-10 is awesome especially for shorter barrels.
Bartleins described as slow makes no sense, they run much faster than LW which are the slow barrels. I'm not buying it, my bet is incorrect understanding of what you actually have.
The reality is for a 308 Winchester a 12, 11.25, 11, 10 or anything in between does not matter. They all will do the same thing with 150g up to the 190g bullets shooting supersonic.
My barrel is a 1:10 24" Bartlein chambered by Dave Tooley. Your experience may be different but mine and several others has been that Bartleins are notoriously slow compared to others. The two Lothars I had were the fastest barrels I've ever had. My AI AE 24" ran 3050fps with a 155 Scenar in a lapua case with only 46gr of Varget. It doesn't get any faster than that.
At the end of the day I'm not happy with the barrel on a rifle that I paid a lot of money for.
Edit to add: my barrel has no England proof mark, it is only marked "AINA 308 WIN".
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With my AIAE 1-12 UK barrel I'm right at 8.7 mils to 1000yds. That translates to 3000+ with my 155 scenars in front of 47gr varget. Never chronoed the load before.
My AE is a 1-10 Bartlein at 22" and it's well over 2650fps, and I don't reload I just shoot all factory ammo.
If you think you got a slow one, buy a new one, but your limited experience doesn't warrant blanket statements. I have Proofed over a dozen AIs and they hammer. The Bartleins are definitely the best of the bunch, including speed wise.
Even more so, the results coming back from the PSRs which are Bartleins from Tooleys are phenomenal.
Seems like you might want to look at your chrono it's probably off causing you to have gass over it.
If you think you got a slow one, buy a new one, but your limited experience doesn't warrant blanket statements. I have Proofed over a dozen AIs and they hammer. The Bartleins are definitely the best of the bunch, including speed wise.
Even more so, the results coming back from the PSRs which are Bartleins from Tooleys are phenomenal.
Seems like you might want to look at your chrono it's probably off causing you to have gass over it.
If I buy another it will be a lothar. I had the same experience with the Bartlien on the used GAP I had and I have seen first hand results of others barrels so I don't see how I'm making any blanket statements, just passing on my experience. The chrono I was using is dead nuts on, my buddies rifle the same day was reading exactly as it should as well. It's the barrel and it's slow. I'm happy with the accuracy though, it groups like a high end barrel should. I'm going to start load development and I hope to find a velocity I can be happy with because thus far I haven't been.
I don't think you can say brand X or brand Y is fast or is slow, there are too many variables. A lot of the barrel makers today offer different twist, different land and grove diameters, you have different rifling styles with different amounts of groves, and most barrel makers have different ideas on what their internal finish should look like. All of this is controlled at the barrel maker level and all of this has an effect on velocity. There is also the chamber and how it is cut that will play a huge roll in velocity for a given round. But all of this is assuming all the ammo variables are controlled very carefully (which they should).
If you are unhappy with the barrel you have then that is fine but also don't blame it on the barrel maker first thing. Also if you are defending a different barrel maker I don't think you can say all of their barrels are "faster" than anyone else with out knowing the specifics, like I mentioned above. Honestly many of us have owned and shot MANY different barrels from a lot of if not all of the top barrel makers over our life and have developed an idea of whos barrel we like for one reason or the other, but can you recall the exact specs of each barrel to make a fair comparison between them? I know I cant. My point is I think any of the premium makers are just as capable of making a accurate and fast barrel as the next. For example I had a factory Remington 40XB that stands out in my mind as one of the best barrels I have ever owned as far as accuracy, speed, and ease of cleaning it was perfect. OH and it was a 308 1-14 twist and hammered with 155g up to 175g. So don't do yourself the injustice of thinking you must have brand X to get a good barrel.
If you are unhappy with the barrel you have then that is fine but also don't blame it on the barrel maker first thing. Also if you are defending a different barrel maker I don't think you can say all of their barrels are "faster" than anyone else with out knowing the specifics, like I mentioned above. Honestly many of us have owned and shot MANY different barrels from a lot of if not all of the top barrel makers over our life and have developed an idea of whos barrel we like for one reason or the other, but can you recall the exact specs of each barrel to make a fair comparison between them? I know I cant. My point is I think any of the premium makers are just as capable of making a accurate and fast barrel as the next. For example I had a factory Remington 40XB that stands out in my mind as one of the best barrels I have ever owned as far as accuracy, speed, and ease of cleaning it was perfect. OH and it was a 308 1-14 twist and hammered with 155g up to 175g. So don't do yourself the injustice of thinking you must have brand X to get a good barrel.
Notoriously to slow? Bullshit! (I'm not picking on ya so don't take it that way) but there are many variables that can cause a barrel to be slow as it's being put and some of the variables we cannot control!
One variable is what chamber reamer is being used/spec. in the rifles build. Different throat specs. on the chamber reamer can cause pressures to be different and that in itself can cause differences in velocity.
What spec. are the bore and groove dimensions? Changing the groove size will have a greater impact on pressures and again this can cause a barrel to be slower/faster. The old saying is looser is faster / tighter is slower does play somewhat of a part here.
Twist? For the most part I'm going to say no. The difference between a 1-12 and a 1-10 is going to be basically nothing.
A 1-10 twist not good for the lighter weight bullets in terms of accuracy? Yes and no! The two most important things with running a faster twist barrel and lighter weight bullets are the quality of the ammunition/bullets and the run out of the loaded ammo. Any run out the ammo has the faster twist will amplify it and it can cause your groups to be bigger. The run out the ammo has basically your already starting a premature wobble on the bullet and when the bullet makes the jump into the rifling the more off center if you want to say it that way the faster twist will amplify it. This applies to any factory ammo as well as you guys handloading. Check your run out on your case necks and the bullet seated into the case. Guys don't check the die set ups and how it's effecting the case during sizing etc....
I've got a factory AI built rifle (here for a shop rifle so any of the guys can take it out and shoot it and or if we go with customers to the range as well as a back up gun for local LE when we work on local stuff) with our barrel on it that Dave Tooley did all the finish work on. I primarily shoot 155 Lapua's in my .308win. guns. that gun will pound consistently right around 1/3moa all day long. Where I point it that bullet will go and it's a 1-10 twist barrel. I haven't clocked it for velocities. Out of curiosity maybe I will take it out this weekend and run some rounds thru the chronograph.
Later, Frank
Bartlein Barrels
