In this case a rebarrel is not practical. So, rebore and rechamber a 300 win mag to 416 Ruger? Shortening the barrel should give enough meat. Ammoguide says it is possible. What say you? Will I have to fiddle with the bolt head?

If keeping the original barrel contour and finish is important, a rebore is the way to go. I've done a few. 375 H&H to 458 Lott. 22-250 to 6.5/284. Both worked well. Feeding was fine as well on the Lott. The 6.5/284 was a single shot.
Bolt faces are the same on the 300 to 416. What action are you using?

Why do you say rebarrel is not practical? Unless you are keeping a unique shape, I always recommend a new barrel.

I'll fess up. I want to do it on a current model BLR takedown. Since the bolt locks up in a barrel extension, I do not even know if a rebarrel is possible. My understanding is that Browning will not sell the extension.

Ok, good reason. But realize you will have a thin light barrel.
The barrel extensions might be cannibalized from barrels though. I have done it on Rems.

I've seen at least two magnum BARs rebarrelled to 458Win.

I don't recall exactly how it was done, but it involved using the breech end of the original barrel and grafting that to the new barrel. The donors were either 7RM or 300W.

They worked fine.

Maybe that is similar to what dpcd has done.

Yes, the barrel extension is not part of the barrel and is threaded on.

quote:

Originally posted by secondtry:
I've seen at least two magnum BARs rebarrelled to 458Win.

I don't recall exactly how it was done, but it involved using the breech end of the original barrel and grafting that to the new barrel. The donors were either 7RM or 300W.

They worked fine.

Maybe that is similar to what dpcd has done.

First I will say never again.
I did this, 300 Win Mag to 416 Ruger.
The barrel on an aluminum frame BLR doesn't come out by any practical means.
Barrel is cut off a couple inches in from receiver, put in mill and lined up. If not straight it becomes junk and throw it away.
Bore out the barrel and thread.
Thread barrel blank to match, chamber and contour.
Having fired a BLR in 30-06 and the recoil is terrible I wouldn't never fire one in 416 anything.

Mark, I am looking at the takedown model, so it all comes out. I am really fishing for someone that will do the work. I searched through various threads, found smiths that have done the work, but none interested and doing it again, but they did not start with the factory takedown model.

I think the takedown makes it more reasonable, but I am not sure where to start: 7mm to 375R or 300 win mag to 416R. I will just have to part with some cash and buy one or the other.

Yes, the TD is a completely different animal from what MC describes.
And yes, you will get way more recoil than you might want if you go to 416.

You could try Regan Nonneman at leveractions.com, I spoke to him a few years back about a similar BLR project (450 Marlin to 458 WSM) and he was interested.

Also measure the muzzle OD, could be too small for a 416 bore.

If you don't mind reloading and case forming just rebore to 416.

I would just get a 30-06 and make it a 400 Whelen; plenty of power without creating drama.