Changing calibers has several considerations. First is the action long enough and strong enough. Will the bolt work as is or will it have to be opened up to accomodate brass with a larger base. Keep in mind you cannot add metal back onto your bolt for a smaller base. Is the magazine long enough.

Lastly, Will the magazine feed lips feed the new cartridge. This can amount to the biggest headache of them all, and few gunsmiths really know what they are doing in this department. With this said, try to stick to something that uses the original case.

Jeeze guys...you want hitting power at 1000 yrds and BEYOND???
.50 BMG.....
(Blowing tin horn here)....Its a Canadian that has the world record for a sniper kill.
It was either Iraq or Afghanistan where one of our boys took out some dude at about 3400 meters.
Now THATS a long shot. Plus...even if you hit an extremity and not a vital organ, you can be assured the target will be dead right quick after its leg gets blown off.

Long actions have been used for short action rounds. Namely one famous but missed example is the M24 Sniper Weapon Systems the US Army fields. They are Long action rifles chambered in 308Win, due to the Army's desire to upsize to the 300 Win Mag when the rifle was being copied from the M40 Marine Sniper Rifle also a Remington action, but in this case a short action.

Currently Rick, the current record with a 50BMG using a MacMillian TAC-50 rifle ( the C15 per the Canadian Forces ) is 2,430 meters or 2,657 yards by Rob Furlong. The shot had a flight time of about 4 seconds over the mile and a half distance.

Shamefully both him, Arron Perry (who had a 2,310 meter hit) and the rest of the unit were accused of something they never did and were forced out of the military shortly afterwords. Why because it was politically incorrect for Canadian Troops to kill anyone anymore apparently. And these fine men paid the price for it .... but that is enough ranting.

Dimitri

Long actions are definitly the way to go, even when using short cartridges. if you seat a Berger so its in the neck and not the case you'll need it. And Berger's like a JAM fit for the best groups. I'm sad to hear you're not doing a 6mm in a fast twist. on a 6mm rem ack. or a 6-284 recoil is so nice. probably still o.k. w a 6.5 and it will be easier to find stuff for. but I still like the 6's

The Savage is the accurate gun you can buy today so good choice .