Are these safe to shoot with modern ammo? Milsurp ammo (I have some). Hand loaded only? I read in Mechanical Variations of the Mauser Bolt Action Military Rifles by James A. Wingate, P.E. pg 27-28
9. 7.65 x 53 mm Rimless smokless power cartridge (1889 Belgian Contract)
This cartridge is a rimless bottleneck metallic case number with a round nose metal acketed bullet of 211-216 grains bullet weight. The case is 53 mm in ength, and the overall cartridge is 78 mm long. The 7.65 mm caliber works out to .30 inches caliber, quite a change from the 11mm black powder job it followed. It originally packed about 39-41 grains of smokeless powder, and delivered a muzzle velocity around 2034-2132 feet per second from a standard long rifle barrel (which was 30.67 inches long in the Belgian M89 and 29.13 inches long in the Turkish M90. The Argentine and the Turkish long rfile modle barrels were of the same length. The Turkish/Argentine was the hotter round.)
Today, it is commonly called the 7.65x53 Argentine, and is loaded a good bit hotter then the original 19th Century version. The last box of commercial 7.65 Argintine I bought is loaded with 180-grain jacketed soft-point semi-ogive projectiles, with an advertised 790 meters per second muzzle velocity (about 2600 feet per second), which puts the loading in the same energy class as the .308 Winchester / 7.62 mm NATO round. The military loading for the 7.65 Argentine in later years was 44.7 grains of power behind a pointed 154grain full metal jacket bullet, and it gave 2.755 feet per second at the muzzle of a Fabrique Nationale barrel of 23.2-inch length. Compare this to the 7.62 NATO and you will find no practical difference. Now.... However, you should be very careful regarding chamber pressures, and shoot only hand0loads with pressures less than 37,000 CUP in the "old" ones (1889-1918)
What say the masses?