Shooting surplus ammo in my bolt guns

I wouldn't. M80 ball can be produced with steel jackets, which may contribute to accelerated barrel wear. It's also not exactly famed for accuracy. Why practice with something that's going to leave you questioning if that miss was you or the ammo?

If you want to practice for cheaper, start reloading. The tools needed will pay for themselves over time.
 
+1 what Hollywood said. I tried surplus and the Tula route for awhile in 308 and 223 but soon figured out I was wasting time and money. Get some factory Stuff from Wal Mart; at least you'll have some decent brass to start with once you start reloading.
 
not even worth practicing with. You can’t practice with ammo that isn’t accurate. You’ll never know what was you and what was the ammo.
If you want cheap match ammo I had good luck with the PMC XTAC Match 308

it was a couple dollars cheaper than fgmm