More serious than my last 338 Lapua post; what about 300 Ham'r? It is not super common but is slowly gaining acceptance. It works well and is reasonably efficient in short 16-18 inch barrels. It is a very compact cartridge using the same case head overall length as 223 Rem. Bullets are easy to get as it uses standard mid to light weight .308 bullets. Recoil would be mild and yet it is proving fairly effective on hog and deer size critters. It was designed for the AR-15 platform but you should be able to turn just about any action chambered in 223 Rem to 300 Ham'r with a barrel change (and maybe some magazine work).