Yeah, I know, there's the AR10. But the 10 is bigger, bulkier, has many non-standard parts. If you weren't concerned with magazine capacity (and non-NATO standard ammo), could something like the .50 beowolf be necked down to a .30 or a .270 and get balistics similar to their longer cousins? I realize you'd only get 10 rounds in a mag but that would be acceptable for a very compact rifle with that kind of power. Also, anyone know if the OAL and case diameter on any of the new WSSM, would lend itself to this?

[url=http://www.olyarms.com/usa.html]Olympic Arms[/url] is finishing work on .223 WSSM and .243 WSSM uppers.  Not the same terminal ballistics of a .308, but looks to be very accurate at longer ranges.

You could probably neck a .50 Beuwolf down to a .30 cal or .270, but you would be getting the ballistics of a 7.62x39 if they were to be magazine fed.  You would have to get one craft gunsmith to chamber a barrel for that case dimension.  

Check my answer over in the post on the 223 WSSM and 243 WSSM uppers.  The Oly Arms WSSM platform opens up many new approaches, but the 308 Win remains hard to rival.

Marty ter Weeme
Teppo Jutsu LLC
Home of the .458 SOCOM

An AR-10 carbine (A2 or A4) weighs nine pounds.  

How much weight are you going to save after you change the barrel and bolt on that wildcat upper you speak of?

A full length Bushmaster rifle weighs 8.27 pounds. A carbine weighs 7.22.

But then, even if you look at a carbine, the barrel will weigh more in a larger caliber, so you might save what, a pound?

Edited to add, now you can get light weight barrels on the AR-10, so the weght savings just shrank a bit more.

I live in the PRK. Otherwise I'd just buy an AR10.