I found very interesting topic "Thoughts on sleeved barrels", and few posts mentioned rebarrelling doubles. Since I would like to discuss rebarrelling only, I started this thread.

Considering that I know for at least 3 Brno Super model 575 combination guns (7x65 R, 12/70), at very reasonable cost, that gave me an idea for rebarrelling combination gun into double barrel rifle, in one of 8x… R or 9,3x74. Frankly, I would prefer more than any other caliber 338-74 R Keith https://loaddata.com/Cartridge/338-74-Keith/1560 . But, since I am in EU, this one is not listed in C.I.P. just an awkward 8,5 x 75 R Scheiring https://bobp.cip-bobp.org/uplo...5-r-scheiring-en.pdf , with very short neck and very steep transition cone.

Ideally, this reworked double barrel assembly should have stainless barrels and possibility of adjustment. To have matched finish on barrel assembly, it should be coated with Cerakote or something similar.

However, according to posts in "Thoughts on sleeved barrels” thread, looks like that the best way to rebarrel double guns is to use one of those with monoblock design.

Considering all that and, as far as I know, Brno Super isn't monoblock, looks like I am talking about an idea that isn’t doable. Anybody knows better?

Rather than rebarreling, what about using an Einstecklauf liner barrel in the shotgun barrel. I have done this in my Ferlach built 7x65r / 16 bore, with an einstecklauf in 7x65r. This turns it into a goid handling double rifle. I can tune the liner barrel to shoot to same point of aim as the main barrel. Accuracy is two shots from each barrel into an iphone sized target at 75m. More than good enough.

If I want an accurate longer range shot, I use the main barrel as before.

And it’s easier to remove, so I go back to having a combination gun.

Mine was made by Zimmerman, but they have retired. Have a look at https://www.keppeler-te.de/pag...e-insert-barrels.php

Onty:

I have custom pistol in .460 Rowland made in Germany. It is not CIP caliber too. I live in Czech Republic. It is proofed as any other firearm, but gunmaker or you must provide ammunition for proofing what I know.

It will be more work, but it can be done.
Jiri