As I understand the monobloc arrangement, the barrel shank is pressed in and either pinned or spot welded in the monobloc. Either method can be "disabled" and the barrel pressed out. I have heard, second hand mind you, of a fellow who replaced the welds with set screws and made it into an interchangeable barrel system. Dunno about that.
The barrel shank is a very tight fit and inserting a replacement would require freezing the barrel and heating the monobloc in order to press the barrel in.
IowaDon on Graybeard Outdoors(original version) has had a few done but I don't know if his gunsmith(s) are still with us. Deaconllb on Graybeard has been frustrated trying to find a currently working "smith to do a barrel swap. I believe gunsmiths with precision machinist skills could do the job, but there is little interest because if something goes south, replacement parts are not available. A barrel swap from a .530" to a .473" base cartridge would require making the extractor leg a little longer by welding buildup and machining to the smaller cartridge base diameter.
From another web site: "The magnum barrels required a magnum receiver as both were different to the rifles chambered for standard rounds. Magnum barrels had an extra pin in the face of the breech that fitted into a groove in the locking bolt for additional strength. Magnum receivers were stamped T/C MAG on the bottom of the receiver behind the barrel pivot pin. Standard barrels for both the M83 and M87 would fit the magnum receivers but not vice versa."
Check to see if the 7mm barrel will fit the action. If there is a pin in the way and the barrel won't close and lock up, try to purchase without the mag barrel, or bargain the price down and either sell the mag barrel or have the pin removed and handload the mag cartridges with reduced charges to 7 x 57 or .280 specifications.
Let us know how it works out.
Last edited by Aagaardsporter; 12/26/20. Reason: add
