or any of the other NE calibers? off the top of my head i remember a Heym bolt action in 600NE thank you for your time

Welcome!

For the costs involved you might as well buy a double rifle.

Possible? Sure.
Expensive? Yes.
Worth it? not realy.

Alf here found a refference to a bolt action version where the 450-400 rims were turned off and an extractor groove was put in to work on a bolt. aparently it was the precursor to the 404 Jeffery.

If you get a 404 Jeffery you will have about the same thing on a bolt action from the same era.

Have an old single square bridge mauser in this caliber, by Rigby, but the barrel is buggered. Need a full magnum action and one of the special sloped magazine boxes that all the brits makers used for rimmed rounds eg .303 in standard mausers and .400/.360; .350 Flanged etc (also have a .350 Rigby flanged but some bastard has re-barreled it- badly!)

Can it be done, without altering the round? As long as the rim is smaller than the bolt diameter, it CAN be done.

However, lots of rounds a made to duplicate the NE's effects, but in a bolt gun

in this case, the 404 jeffery (and 416 taylor) are one for one replacements.

Today, there isn't a NE round that can't be duplicated in a bolt gun.. but they will never be double rifles.

Here is an example of a bolt gun chambered in a Nitro Express round.

http://www.champlinarms.com/Default.aspx?tabid=30&mid=3...StyleID=2&GunID=1306

My Cogswell and Harrison "Certus" magazine rifle is a 450-400 3 1/4" NE. The Certus was the only bolt action designed for the long rimmed NE rounds. The rifle was only offered in 450-400 3 1/4 and 450 NE. They have a long magazine the extends from the bottom of the stock.