I have an old sporterized GEW 98 model dated 1918 Amberg on it. I last shot the gun in 1976. I truly don't remember if the gun is a 7 or 8mm, as I cannot find the old box of Remington shells that I used back then, although I know I still have them somewhere! :-) Any way to tell without killing myself? Also, I see some talk about the use of lower pressure shells in older guns. Can anyone tell me what that is about?