Bushmaster Varminter .223, want .243 upper & barrel for deer any recommendations?

[Ridge Runner]

Originally Posted by 308

Another possible option, that I think will fit your current platform is Remingtons new 30 AR cartridge. Its a 30 cal that is getting dang good ballistics for a ar 15 frame 30 cal, about 80% of full power 308. That would be a much better option than 22 or 24 calibers for deer. Just my lowly opinion of course: 308

80 % of a 308 win. is the 7.62x39 russian or the 30/30 win.
RR

[Varmint Hunter]

Some very helpful onfo can be found here.

Remington Introduces new 30 Remington AR Cartridge « AccurateShooter.com Bulletin

[ConservativesUnite]

Yes, I was talking about .243 WIN. I want a caliber that I can buy off the shelf ammo, no custom stuff. Maybe I will just stick with the trusty ol' Win 94 30-30 or get a Browning X-bolt in 270 WSM.

[sambo3006]

I'll second the 6.8 SPC. It will drop right on your .223 lower. I don't know about smaller towns but ammo can be had at places like Bass Pro Shops or Cabelas. I have a Rock River Arms upper on order for deer hunting right now. Figure on putting a red dot sight on it for still hunting and deer drives. Even out of a 16" barrel it has fairly impressive ballistics on the AR platform. The 6.5 Grendel is a proprietary round and really suffers when used with a short barrel. Unless you are talking long range shooting, it offers nothing that the 6.8 SPC doesn't. (I would like to have one with about a 22" barrel though, but kind of pricy.)
The 7.62x39 is certainly another option. Not quite as flat shooting but would be great on deer at moderate range.

[msalm]

6.5 grendel Wolf Gold ammo 120gr sp's are still $12 a box of 20 thru Midway... Cheap enough to buy a bunch. Out of my 22" Grendel they shot 1 1/4" or so. Loads with the 120gr Nosler's and Sierra's went sub 3/4 MOA. I built my Grendel off a worn-out 30" Krieger 6.5-284 barrel. It's amazing how GOOD that last 24 inches of barrel looks like after you trim 6" off the chamber end and one at the muzzle, and all for $50.

[puppezed]

If you need to use the same lower I´d take 6.5 Grendel but take note what sambo3006 said previously about the barrel lengths.

IMO best solution would be to buy a new gun. DPMS has various models for example in .243 Win, .260 Rem and .308 Win calibers. Armalite makes AR-10 in .308 Win.