Thats one of the unissued M48's
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I found one like that still NIB in a pawn shop. These are awesome 8mm mausers. There was a run of the well used m48's for a while too. I believe these had the shortest bolt length of the 8mm mausers.
On the sks make sure you disassemble the bolt and remove the firing pin to clean it out good so slam fires won't occur. Just make sure its dry and clean when you reassemble it.
There was a difference in the american manufactured 7,62x39 ammo. It was .308" diameter and had soft primers. It made the imported rifles in 7,62x39 very inaccurate because they had .310"..311" bores and some had slamfires because of the soft primers. I shoot mainly new wolf ammo. But i'm sure any russian or european ammo will be ok to shoot. If you reload the 7,62x39 make sure you use the CCI nato primers there made for the floating firing pins.
SKS Warning; Once you shoot it, it can cause you to buy more sks's, shooting the first one and seeing how much fun it is to shoot can start the disease beaware......it could cause a feeding/buying frenzy and you may go looking for a Russian, an Albanian, a Yugo and a Romanian sks soon after. Don't smell the cosmoline for too long too. This can cause you to reach for your wallet everytime you smell the cosmoline too. Trust me i know......