I have a 7x57-1895 Chilean Mauser that was my Dads, and it very accurate, 3/4 to1inch groups with my hand loads. But here's the thing, many years ago he had the barrel cut and recrowned, had the sights removed, the bolt fixed for a Winchester type safety and drilled and tapped for scope base. Then dropped it in Reinhart Fajen wood stock. Now I have it and further had work done, recrowned with a target crown, glass bedded, and a better trigger installed.
Also I have found with many Mausers they like a heavy long bullet to get your best accuracy. I shoot a Sierra 160 gr. Spitzer B.T. out of mine.