Love the old razor. Without being able to see the head stamp on the casings it is hard to guess the date. No measurements hurt as well. Betting they are 30/06 casings. The cartridge has been around since 1906 thus the 06. It was our primary military cartridge for approximately the next 50 years and to this day is considered the benchmark for comparing hunting cartridges. I, as many, still regard the 30/06 the perfect compromise in power vs. recoil. The age could be any where between it's 1906 intro to current day. Yours look they have been in the ground many years. Congrats.