Have a few 7mm military mauser rifles and while hardly match rifles, they'd be just fine for deer hunting. Actually, a couple of my 7mms shoot pretty darn good for a military rifle. As suggested, I'd give the barrel another good cleaning and probably do a crown job on the muzzle before replacing the barrel. I've improved the accuracy of a number of mausers or other military surplus rifles just with a crown job, something you can do yourself. Just something as simple as a carriage bolt or a large brass screw using valve grinding compound on the head of the bolt or screw and using it in a drill to lap the end of the bore may be sufficient to correct a damaged crown.
By the way, you can buy a sporter replacement barrel from Midway for around $80 that is prethreaded for a mauser action and short chambered. There are a number of cartridges you can choose from, including the 7x57 mauser. Since they are short chambered, someone will need to run a finishing chamber reamer into it to set the proper headspace when installing the barrel.....a relatively simple task, but recommend using a gunsmith to do this since he will have the expertise and tools to replace a barrel. Now if you want a new replacement military contour barrel, they can be found, Walter Lothar barrel company makes one and Cole distributing still has some new Norwegian 98 mauser barrels, but they are threaded for only large ring mausers and available only in 7.62x51 (308Nato)