Gew 88 Questions (Not Mauser but closest board I could find)

Today I will be purchasing this rifle for 100$, I've done a fair bit of research on it but the one area I've had trouble with is the bore sizing and what I should chamber in it. Overall just some suggestions on anything would be super helpful!

I'm new to this old of firearms collecting as I normally stick to classic mil-surp firearms from the cold war, I currently have a P01, Makarov, SKS, Mosin, CZ82, PM-63 and a few other entry level collector firearms.

Thank you again for any assistance, after I purchase it ill post some better photos than the ones I was sent. Even if its hard to chamber or not safe to do so without making the rounds myself 100$ for a antique wall hanger cant hurt.

Edit: Buying from a friend so not a sketchy price as would be assumed!

Attached photos, I got of the rifle. All matching parts serial number wise. Pretty good deal for 100$

You have a Gew-88/05 rifle . It went to Turkey near the end of WWI or a few years after . The rifle shows to have it's original barrel still on it . The stamping on the rear sight shows some land wear . Your groove should not be any smaller than .3208 and the lands are shown at about .312 on the sight when the rifle was measured during the 05 conversion . You can slug it to make sure . So any of the standard US made 8x57mm ammo [ older is better as they are .321 bullets for sure ] should still be loaded with .321 bullets and will shoot fine in your rifle .

There have been previous posts about these rifles. A search should help you with more information.

That is a very good-looking Gew.88. Better than anything I've seen up to now here in Mauserland! $100 was a steal.