canon6
The original CETME rifle was made for a shortened cartridge ala the 8mm Kurz. When it was decided to adopt it to 7.62 NATO the German engineers (working in Spain) enlarged the action. Severe problems arose with reliability of extraction. The pressures of the 7.62 NATO had the cases still gripping the chamber walls when extraction started. This caused malfunctions as there was no primary extraction in the delayed roller locking system with it's non rotating bolt. The solution was a milder pressured cartridge, hence the 7.62 CETME. That cartridge was developed for the CETME rifle not the FR7 and FR8. The German engineers then discovered that by fluting the chambers the extraction of 7.62 NATO ammo in the CETME rifles was reliable. All issued rifles were recalled and their chambers fluted. The German engineers returned to Germany and the H&K G3 was born out of the CETME design. All this is well documented in numerous books such as Small Arms of the World, etc. Concurrently the Spanish had a lot of M93/M1916s in 7x57 and M98s. They rebarreled them with .7.62 barrels and reissued them to police and border guards as FR7s and FR8s. The Spanish manual for these rifles lists 7.62 NATO as the standard ammo for them along with the remaining supplies of 7.62 CETME ammo. 7.62 NATO is standard.
There is a considerable amount of "published" pressure data, both old and new. My point was that many times the modern piezo measurement of psi is confused with the older CUP measurement of psi. They are different. As an example of the error in your quote of the 7.62 NATO being "proofed" at 50,000 psi. That is not correct. &.62 NATO has always been "proffed with the "Cartridge, 7.62 Millimeter NATO, test, High-Pressure M60 cartridge" which develops 65,000 to 70,000 psi based on a case mouth transducer which is what the Arsenals use for 7.62 and 5.56 NATO ammuntion testing. Another difference between "published data is that for the 7x57. The CIP (Europes equivelent to SAAMI) says it is 57,000 psi.
None the less you very nice scout conversion is made for 7.62 NATO ammuntion and should do well with it or equivelent handloads. If the rifle is still a "work in progress" you might consider a cock on opening conversion. I've done several (including my M1916 Ovido action) and they are a worthwhile conversion. BTW; how well does she shoot?
Larry Gibson