With the advent of the CMP GSM Vintage Sniper Rifle Matches, Hornady is making match ammo for the 7.62X54R. I haven't seen any as yet but I understand it will be available for the CMP Eastern & Western Games as well as Perry.
Personally I wont shoot surplus ammo in mine. It (91/30) has a good bore and I load Sierra .311 bullets with Winchester Brass. It shoots quite well in my rifle.
I put on a CPM-GSM Clinic and Match yesterday, there were three Mosin's in attendence, the surplus ammo gave fits to two of the Mosins. I loaned mine out, with my ammo, and it produced no problems.
Yes surplus ammo is cheaper then quality reloads, but I'll take accuracy over cheap any day.
A good 91/30 will shoot as good as a finish model if one learns to shoot it, and takes care in the loading of ammo for it.