On Guns America I see a 9 pound Hammerless 500 BPE 3 1/4" double by Webley & Scott

built very late in the nineteenth century. Assuming it is mechanically sound, could

a second set of Bbls be used on this rifle in 375 flanged magnum NE or 450/400 NE 3"

Jeffery with no ill effects?

Possibly. Maybe even probably.

But if it fails proof, you've just shot both cats.



I think we can safely assume that the much thicker chamber walls of modern steel in the proposed new barrel-group would be safe, so the weak point will be the action, specifically the bolting system, and the junction of the action bar with the standing breech.

Let's start by putting it to the test on paper:

The .500 BPE has a case-head diameter of 0.58 inch and turned up 11 tons of pressure.
Doing the sums, we find that equates to 2.9 tons of back-thrust on the standing breech.

The .375 Flanged Magnum has a case-head diameter of 0.50 inch and produces 18 tons of pressure.
That equates to approximately 3.5 tons of force on the standing breech.

The .450/.400 NE has a head diameter of just over 0.54 and a pressure of 16 tons.
This gives around 3.7 tons on the standing breech.

As you can see, the .375 Flanged Magnum chambering will increase back-thrust on the action by some 20%, and the .400 Nitro by closer to 30%.

That's like firing a proof-load every time you pull the trigger.

Of course, if it passes the new proof, done properly, then all is well.

Is it worth the risk? Only you can decide!

Note: Those figures are for comparative purposes only, they don't account for case-web strength, brass 'grip' in the chamber, the rim recess at the rear of the chamber, or a myriad of other minor variations.

Hope you find this helpful.

Thanks, yes it is helpful. I enjoy gainning knowledge about DR's very much.