What left action best for making a Left Hand 6.5 creedmoor
#4

For hunting, the type of hunting you're doing will matter also. If you're shooting rather long ranges, then the action you pick might be different than that for hunting where you're WALKING long ranges. Hunting DOES, however, in general dictate that you want a repeating action, rather than a single shot action, which would be favored on the firing line.
Remington 700 and Savage 10/12 actions are available enough, with substantial aftermarket support to make them viable options. The Savage would be easier to build yourself, while the Rem easier to have built. Drop in barrels are available for the Savage that you can install yourself with under $200 in gear. I wouldn't venture that you'd ever cross over into a long action with the 6.5CM, as even heavy for cal bullets should fit in a short action mag box. Plenty of 700 clone custom actions are readily available on the market that often save money over buying and blueprinting a Remington factory 700 action, but if you're just hunting deer at 200yrds or less, all of that is a waste of money anyway. I built a 284win on a Stiller Predator a few years back that I was quite fond of, which run just under $1,000 for the action - considering MSRP on a Rem 700 action right now is $550-600, you could get it blueprinted and built for that much. Start with a $377 Rem ADL from Walmart, and you can get it done for less still.
For target shooting, the action type would wholly depend on what type of 'target shooting' you'd be doing. If you're shooting 1,000yrd benchrest, the action would be different than if you're shooting 100/200yrd benchrest or 600yrd F-Class or the hot craze of tactical rifle matches. A blueprinted 700 or Savage would hang at any of these matches, at least at a local level, but repeaters aren't the norm in most bench rest matches, and there are better suited custom actions available for those applications. What 'weight class' you want to shoot in also dictates what action you might want to shoot. I wouldn't hazard to speculate on what action would fit, since it's such a broad category, without knowing the specific type of target shooting you might have in mind.