Congratulations! I've had a Yugo M48 for quite a few years, mine looked new when I got it. A well made rifle using the Mauser M98 pattern. Not completely identical to the German Kar 98k, but many parts will interchange. I don't know anything about the M48-B, but it can't be much different.
The safety being "stuck" is PROBABLY an easy fix. Can you disassemble the bolt?? (do you know how?) I can walk you through it, if you don't and I'm sure there are Utube videos that do.
What you need to look at is the EDGE of the "notch" in the safety that cams the cocking piece back when you put the safety ON. You may need to touch it with a file, or a stone to put just enough more slope on it that you can operate the wing with finger strength.
But FIRST, strip the bolt and clean it well. Always make sure that the problem isn't crud, crap, dirt, oil turned to glue over time, etc., BEFORE touching any metal work.
Also what is the cheapest non-corrosive 8mm ammo I can feed it?
After you get past the start up costs, the cheapest non-corrosive 8mm ammo you can feed it is your own reloads. If you don't want to go that route, then just watch the market for deals. I don't bother anymore, since I bought a few bandoliers of Turkish ball, back when it was dirt cheap, for my "war reserve" and over the course of a summer bought several boxes of Remington ammo (one box a month or so,
, and a few bags of new brass at gunshows, so I shoot handloads for plinking and practice.
It is true that the Remington stuff (and other US factory loads) are not as powerful as the European stuff, but they are enough for regular big game hunting, and an excellent source of reloadable brass. And, if, for some reason, you can't get 8mm Mauser brass, you can make it out of .30-06 fairly easily. (another plus, if it matters, is the US ammo doesn't kick the snot out of you as badly as the European stuff does...
)
There are a lot of stories about 8mm Mauser rifles and the change in bore size. Some are conflicting. Part of the reason for some of it might be translation of the German Fraktur script. The "I" and the "J" look nearly identical.
The change from a .318" bore to the .323" bore happened well before WW I. The Spitzergeschoss bullet was the reason. What happens after depends on who is telling the history, and I, personally can't say, but some versions seem more sensible than others. Here's some of the things I've heard, judge for yourself..
When the bore size change was made, the rifles in German service were (all?) converted for the new round.
a) they were rebarreled
b) they were rebored
c) neither, but the chambers were relieved to allow for the larger bullet. Shooting a .323" bullet down a .318" bore is no big deal, IF THE CHAMBER is cut to allow release of the larger bullet without raising pressure to dangerous levels.
d) most were converted, some weren't
(you pick what seems like what they would have done...
)
Rifles in civilian hands were NOT converted to the new round's bore (unless the owner personally had it done), and civilian rifles in the .318" bore size continued to be made for some time, as well.
The Spitzer bullet ammo was designated with an "S" Some say the "I" for
Infantrie, (.323) and "J" for
Jaeger (hunter, .318"), some say the I is supposed to be a J, some say the J is supposed to be an I, and its misreading German script, some say other things, it gets very confusing.
The main thing is, in agreement, however, German 8mm Military rifles made after WWI will have the larger bore diameter. Your Yugo, made after WWII, will also have the now standard larger bore diameter.
Any ammo you are likely to run into will also be the larger .323" diameter, .318" 8mm ammo still exists (I'm pretty sure
) but you'd have to hunt it up special, I think. Not that I ever specifically looked, but I've never seen any casually, and I've seen a lot of ammo over the years.
Take apart your bolt and clean it, see if that doesn't solve the "stuck" safety. STIFF is not the same as "stuck" Some of them are VERY stiff.
If your M48 has the metal disc with the hole in the stock (mine does) you have all the tools you need to take the bolt completely apart.
Good luck, let us know how it goes, and how we can be of further help!