That's how I started reloading my '93 MAUSER Carbine. I brought home 60+ ISRAELI 8mm cases as a souvenir from a trip to ISRAEL IN 1968.
I found a 1893 7X57 carbine in 1975, in a barrel of 1888 "Commision" Mausers. $40.00 at BIG5 Sporting Goods. Bore was BRIGHT & SHINY, metal & wood 90%. LUCKY find. I bought the one box of ammo they had. I bought HORNADY bullets & dies at BOWERS WHLSE. No brass on hand. Then I remembered the box of 8mm brass. I lubed bodies & inside the case neck and passed them through the 7mm sizer. Trimmed the few that needed it and loaded a starting load with H4895 & SIERRA 150gr HPBT MK Rejects, that I bought at the old Sierra Bullet factory in SANTA FE SPRINGS, CA. A dollar a pound. Great plinking loads, you bought what ever rejects they had on hand.
Brass worked great, no neck thickness problems. I brought the brass home with the hope I would be able to use it someday. I went to the Rifle Range with my Cousins when in ISRAEL. Had a chance to shot the DWM K98KAR my Cousins Father had used in the WAR FOR INDEPENDENCE. I was surprised to learn ISRAELI AMMO was boxer primed.
I must have reloaded them a dozen or more times, never lost a case, never had a primer pocket expand, trimmed twice, I think.
So go ahead and neck it down. I can't speak to Prvi Partisan rifle brass. I did have a problem with some 9mm years back when it first came into our country. TIGHT primer pockets. Haven't tried any since.
I turned it into a SCOUT RIFLE a few years later by removing the sights & dropping it into a E.C. BISHOP stock. Had a GOOD GUNSMITH cobble up a SCOUT SCOPE base for it & stuck on a BURRIS SCOUT SCOPE. BOY HOWDY did it shoot. I'd loaded some light lead load with the LYMAN#287405 over UNIQUE for 50yd shooting with the iron sights. I got 2" 5 shot groups from the bench with that load & 3 shot 1 1/2" groups with JACKETED loads.
Now with the scope at 100yds I was getting 5 shot Cast groups of 1 1/2" & 3 shot JACKETED groups under an inch. With that 2 3/4X scope I was tumbling jackrabbits at 100ydsyds+.
That is a gun I WILL NEVER SELL. A blast to shoot lead all day long, 14.5grs over that #287405 sized .285, cast of straight Lino & lubed with WLL BAC. Rifle has a true groove diameter of .284, a real surprise to me. A VERY LUCK FIND.