Home Forums Hunting & Shooting Africa 6.5 Swede for Plains Game

As you're talking about a backup rifle, rather than a second rifle intended for a different purpose than your -06, IMO the backup should be effectively similar in terminal ballistic efficacy as the primary rifle.

Any of the cartridges you mentioned, with the appropriate bullet weight and construction, are functionally equivalent for the range of PG you mentioned.

I would have no hesitation to use a 6.5x55, with modern loads and a bonded or monolothic 140 grain bullet for all the PG you intend to shoot - either as a backup or a primary rifle. Straight line penetration is important for killing power and few of the cartridges you're considering, including the -06 with 180s, is likely to outperform the 6.5 with 140s in that task.