The cartridge is a military cartridge, but not all rifles in 30-06 are military rifles. Mausers, 1903s, M1s, etc are military rifles that can be chambered in 30-06.

I looked through their catalog, the only one that comes close to a match is the M18, which was only made as a hunting rifle. Never marketed as a military arm. This is somewhat of a sillty splitting hairs argument, but the "must reply" bug got into me. ...

The only reason this is an issue at all is what it tells us about the possible shooter. If he used this gun, then I may push back on the idea that he's a far right guy, particularly not an accelerationist. It's a thin read, I admit, but those types of guys get fetishist about their guns

The term "military rifle" muddies that water

I severely doubt a fetishist into far right stuff would use a low quality sporterized Mauser. They typically want to be true to form and use actual Nazi stuff.

It is worth noting that the Mauser M18 is not actually a Mauser, it's actually a rebadged Sauer 100. The Mausers I am referring to are actual, Mauser designed CRF rifles.