My Stag 10 parts finally shipped and should be here tomorrow.  I have to have a barrel with no muzzle threads (state law) and it looks like a custom barrel will be the path of least resistance to get what I want & need, which opens up some options.

I handload, so that isn't an issue.  

I already have a M1A in 308 and a bolt gun in 243 (and loading supplies and tools for both).  

My instinct is to just go with a plain old 308 barrel, but given the options I thought I'd do some more thinking about it since the cost of the barrel itself will be the same either way.  2nd instinct is 6.5CM, but kinda lukewarm on that caliber.  

99% of my shooting will just be for fun at my clubs 100 & 200 yard ranges, although there is/may be some opportunities to go longer.

100-200y?  At those distances, it really isn’t going to matter much.  Some may offer less recoil, but stuff like 6CM is going to have extremely short barrel life.  

I’d say 308 just due to cost and longevity.  6.5CM as the alternative.

308, and 2nd choice would be 6.5C.

I really want to say 7-08.  The one I had shot lights out, but nothing I tried could get it to stay on target.

After each shot, my crosshairs would be 4-5 feet off target when it settled.  They guy I sold it to loves it, but has the same problem.

If you are going to build it like a long range gun then cm.  If not then 50/50 between cm or 308.  They are equally at 200 yards. Cm outshines 308 out past 400. So if you ever want to bang steel at 800 then cm is the way to go.


As far as effective hunting ranges...they are again pretty equal. They drop under that 1k ft/lb of energy mark around 800 yards.

Get both.... I'd probably do a heavy barrelled 6CM upper for varmints and a lighter 6.5CM upper for larger game.

If I was going to build one, it would be in 260 Remington, because I already have some 260 Rem components.   However, the 6.5 Creedmoor has gained enough popularity and most especially AVAILABILITY that I would recommend someone else building on go with that cartridge.  

Due to the great ballistics of the full size rifle cartridges in 6.5mm (260 Rem, 6.5 Creedmoor, 6.5x47 and in long action the 6.5x55) they begin to surpass the energy of the 308 loads at around 300-400 yards, and from then until going transonic, retain more energy than the 308 rounds.  

If someone has an immense quantity of 308 ammo on hand, or has special access to 308 ammo (such as military access) then I would go with 308, but otherwise the 6.5 mm cartridges I mentioned have less recoil, better ballistics, better wind resistance, longer range, and from 300-400 yards, more energy than the 308.

What about 243? You are already loading for that caliber, plus I always though a 243 semi auto would be an interesting gun. That's my suggestion. If not, 6.5 Creedmoor like everybody else.

Always wanted a 7-08, easy to form 308 brass. Also have one in 260 never got around to playing with it before prices went nuts.