260AI Criterion Barrel, match or standard chamber?

[Trapper458]

Hello,

Is anyone shooting a Criterion 260AI barrel with a match or standard chamber? I'm planning a 260AI on a Savage Model 12 with detachable magazine and am wondering if you stay with a cartridge OAL of appx 2.80", how close to the lands are you able to seat 139/140/142 gr bullets? I spoke to Jim at Northland Shooters Supply and he recommended the match chamber but after reading a post in this same forum by "capreppy", I'm concerned the match chamber with 0.160 leade will be too long and maybe better to try the 0.98 leade on the standard chamber. Anyone have any experience with this barrel in either the match or standard chamber?

Regards,
Traper458

[Billch]

Standard chamber? As far a I know there is no such thing in 260 AI. If memory serves correctly, Ackley never did a "260 AI". It's easier to say than 6.5mm-08 A-Square, Improved, 40 degree shoulder. That's why everybody calls it a 260AI. Not to quibble but it sounds like Jim just has two different reamers that he uses. Nothing wrong with that. There are so many different ones out there though.

If you want to use your rifle as a repeater with the 260AI you'd be better off going with the shorter, .098, freebore. I don't think you'll be able to get close to the lands and be under mag. length with the .160 freebore. Fore example, if I'm doing my math right, a .160 freebore would put a Berger 140gr. VLD at the lands with an OAL of about 2.972. With a .098 freebore you'll be at the lands at 2.882. (or there abouts)

If you want to maximize the case capacity and shoot the heavies you'll have to single load. If you want to shoot the 140gr. class bullets from the magazine you'll be giving up some powder capacity do to the bullet base protruding into the case.

Something else to consider is your bullet choice as it relates to OAL. A 140gr. Nossler Accubond will seat .184 shorter OAL to the lands than a 140gr. Berger BT Target LR. The difference in the length of those two bullets is .013. It's the shape of the nose, or ogive, that makes the difference.

You're going to have to compromise somewhere.

I don't have a Criterion barrel but I do shoot a "260AI" of my own spec.

B

[alphapygmy]

I'm using a Criterion 260AI with the match chamber. I currently use the barrel on a long action but put a couple rounds in a short centerfeed mag so you can see about how long they run. The shorter round is a 142 SMK .020 off the lands and runs 2.895" the longer is a Berger 140 LR BT .020 off the lands and runs 3.005." My short action centerfeed mags have 3.00" to use so the Berger is a tad too long. Even if it ended up at 3.000" eventually you would end up chasing the lands and have round too long to work. The 123 Lapua Scenar is short enough to work in my mag also, no pic though......

[Trapper458]

Thanks to both of you for your responses. As I will be using the short action with the detachable mag, I've decided to go with the "standard" chamber and see how it works for me....thanks again,
Regards,
Trapper458