I have been happy with my M-48, got it about 3 years ago, have around 800 rounds through it, mostly surplus. My initial complaint was the sticky bolt problem, and the bolt face would rub on the cartridge heads on most ammo. Those problems are all gone after it got broken in, took around 150 rounds before it smoothed out. The gun appeared new when I purchased it. Put it through the traditional break in procedure for all my new center fires to help the barrel in the long run. I also use a bore guide device to clean it from the action, this protects the muzzle area.
It is very reliable and exceptionally accurate, shoots well offhand too. Some of the surplus ammo that I have used has had case and primer splits, when that happens I field strip the bolt and run WD-40 into the bolt body to get the corrosion out. I do clean the barrel immediately after shooting the same day with black powder cleaner in the bore, and on the bolt face. I then use Hoppes #9 inside the barrel and action, let it soak over night with the rifle in a horizontal position, then clean it again.
It is amazing the amount of copper and powder fouling that will seap out of the bore the next day, even if I cleaned it the initial day properly. I do the two day clean with all my centerfires.