New AI AT or AXMC - Set Up Questions - Barrel Length and Spuhr Scope Mount

[Monk Medic]

So I think it's finally time to break down and get the Sage Green AXMC .308W that has been on my mind.
I picking .308 as I've got a ton of it, it's readily available, cheap to shoot, and works in my range space.

AT vs AXMC?
Not sure I'd ever want to change caliper, did consider the AT series, but owning a AXMC already I like the adjustability of the stock.
The AT is considerably less costly, if I was going to keep this just a .308 gun is it work moving to the AXMC?
Thoughts on this?

Barrel Length Choice?
I see the AI offers the 20, 24, 26" barrel lengths.
I'm strongly considering the 20" barrel for reasons of being compact, lightweight and the distance I'll be shooting out to, 1,000 yards, actually most will be between 300 and 750 yards.
Anyone have any muzzle velocities (MV) for their own rifles on these barrel lengths?
Thoughts on the 20" over the longer ones, other than losing MV?

Mount Question?
I've picked the Nightforce ATACR 5-25 Mil-C as my optic, have that one of my other rifles and love it, but my question relates to the mount.
On my other AI, I used the Spuhr one piece mount, have been very happy with it.
Anticipated range here with this rifle is 1,000 yards and in.
I understand that the AI AXMC has a "30 MOA" rail inclination, do I need to consider a Spuhr mount with inclination built in, or just choose the 0 MOA one?
The ATACR has 120 MOA adjustment, and shooting out to the range I anticipate, am I good to go with the 0 MOA Mount?

Anything Else?
Anything else I've overlooked, that you'd suggest, etc?

Thanks much!

 

[Commander Shepard]

AXMC is the long action (for 300WM, 338LM etc). It can still run 308 but what I think you're after is the short action AX308, which is what I have. As far as chassis adjustability goes AX308 and MC are the same.

With my 20" AI barrel I get 2620fps using factory 175gr FGMM, and right at 2720fps with a 26" Bartlein. If you're shooting PRS or some other type of competition I'd try to get every last fps I could, otherwise 20" is fine. I am using my 20" as a burner practice barrel and 26" for comps.

You'll be fine with a flat 0MOA Spuhr.

 

[PBWalsh]

I’m basically only going to be shooting .308 when I buy my AT. However, I am in Alabama and will probably never shoot past 1,200 yards. If I had access to a mile, I’d consider just saving more for the AXMC. For MY needs, the AT is just fine (plus I love thumbholes) and do not NEED the adjustments and features on the AIAX.

Picture below is some estimated 20” velocities based on information gathered here in the reloading depot. The ballistic data is using JBM outputs using the average velocity at sea level with default atmospheric conditions. Prices are from Midsouthshooters.com and the WTC Flatlines are from their site. I did not include Berger and Sierra offerings in the data because I thing the Hornady projectiles offer greater BC per penny spent across the board until you step up to the WTC Flatlines.

From what I can see here and using the berger twist rate calculator, the 155 grain ELD-M gives better to best results with the 1-12” twist from a factory AI barrel. Personally, I’ll after I burn out the factory barrel, I’ll go with a 1-9” to use the 225 ELD-M and 180/198 WTC Flatlines.

I include cast bullets on here because I’d like to use those as a trainer barrel because AI does not offer .223 bolt faces. Probably cast after I burn out my factory AI barrel. Buy a 1-9” for the ELD-Ms and a 1-10” for cast. Run a 230 Lee casted bullet at 1050fps and never wear out the barrel for some solid and cheap practice under 250 yards.

Anyways, if you buy ANY AI rifle, its a sound decision. If you only want to shoot .308 or its offspring and do not need or want the features of the AIAX, buy the AIAT and save 3-3.5k.

 

[hollowoutadime]

AI is selling new AT's with 6.5cm barrels. I think you should go that route. Loaded ammo cheap plentiful, better ballistics, less recoil. Just bought a second AT with this barrel two weeks ago. Pulled the 6.5CM barrel (it's worth more than a 308 barrel), and am running 6br. I have the short action AX as well. Folds nicer (right folding vs AT's left) enclosing the bolt fitting in a drag bag easier. The AT is a good value.