300 RUM to 300 NM chamber

[Taylorbok]

I've got a barrel chambered for a 300 RUM I'm no longer using and buddy is needing a barrel for a 300 NM he is building.
From what I can figure if he set's back the barrel about 0.5" that should be enough for the NM to clean out the RUM chamber.
Here is the drawings I was referencing.
Let me know what you figure.

 

[lancetkenyon]

What is the shank diameter on the barrel? I like the 1.250" for the NMs. If your RUM barrel has the 1.250" shank you should be OK.
Also, how many rounds down the barrel?
Personally, I would just start with a fresh blank unless it is a really low round count carbon fiber barrel or a direct swap pre-fit he would not have to mess with.

 

[Taylorbok]

Yes it is 1.25" shank. Shank isn't super long, I'll have to analyze that a bit.
It's got 450 ish rounds through it. Normally I wouldn't suggest using it either but he's wanting to shoot a match early May with it and we can't seem to find a barrel he wants in stock in Canada

 

[lancetkenyon]

Same action/tenon/threads? Maybe just spin it on and shoot the match with the RUM while waiting on the right barrel?

 

[Taylorbok]

Barrel was off a Rem 700, He will be using a Cadex action.
I just realized the Cadex is 18 TPI instead of 16 so that's out the window.