I'm relatively new to old military surplus shooting but from what I've heard the general rule of thumb is that military surplus (older stuff, not modern) ammunition is corrosive or at least should be treated as such since it may not be really known whether it is or not.

At the Oaks show last weekend I came upon a table that had an ammo box or two filled with zip-lock baggies of loose ammo and a price sheet. The line on the sheet that caught my eye was "Portuguese 8mm non-corrosive - $13/50 round bag." I know that newer factory non-corrosive production (like Prvi) can go for around $15 or more for a box of $20 so the price really caught my eye. I was sort of skeptical about it being non-corrosive surplus but thought I'd take the gamble anyway. To look at it I wasn't even sure it was 8mm because I wasn't familiar with the head stamp and it looked like he had other calibers on his price sheet also in baggies all in the ammo can. The table "owner" was busy doing like 3 different PICS checks and his helper wasn't too sure about it either but he thought it was a good price too if it was right. I bought two bags for 100 rounds total at $26 ($.26/round).

After I got home I did some searching online and sure enough I found info on 1970s production Portuguese 8mm non-corrosive ammo made at the FNM plant which would explain the head stamp: FNM 71-9. I believe the 71-9 means 1971 production year lot #9 based on my research (funny thing, out of 100 they were all 71-9 except for one 71-4). The research also suggests that this is very good, consistent, accurate ammo and possibly worth much more than I paid. An auction on GunBroker back in June was for 180 rounds sold for about $120 shipped ($.67/round) so I'd say I did good. Apparently it's also pretty rare to find anymore. The only thing I regret now is not buying all he had. I think he only had maybe two more bags, but still. When I get time we'll see how they shoot in my K98.