The original 8x50R used a 244-grain RN bullet: just TRY finding them! As well as Austria-Hungary, the ammunition was used by the Kingdom of Bulgaria in their Model of 1903 rifles: identical to the Austro-Hungarian rifles except for the DATE on the left-hand Receiver Rail and the Royal Bulgarian crest on the Receiver Ring. Sporting ammunition was made in England for a short time, also.
There were none of these rifles built after the end of the Great War.
In the 1930/31 period, the successor states of Austria and Hungary both adopted a new cartridge, the 8x56R. Bulgaria followed suit, modifying their own older rifles to handle the new ammunition.
So the new ammunition, in the old rifles, was used by THREE countries.
Also in the 1930s, many of the older "long" rifles were modified into shorter, handier, "short rifles". This is what you have. They were completely rebuilt to "new" condition and then, when the War came, they were not used at the Front because every effort was made to keep rifles in the combat zone all using the same ammo: it was hard enough to supply 8x57.... without throwing in the supply problems of adding 8x50R, 8x56R and 7.35x52 and .303 (remember those 130,000 rifles they got at Dunkirk? They used them doing guard duty!).
These rifles were kept in storage for a long time and then released very late, accounting for the good condition of most of them. Prices have been kept low by the facts that most folks don't know much about them, that very little military ammunition ever was surplussed and that sporting ammunition was unavailable in Canada until a few months ago.
But they are genuine rifles which were used in the First World War and again in the Second. They ARE History.
Austria-Hungary had been a major industrial Power before the Great War, but the successor States were flat broke, hurt badly by the War (utterly horrendous casualties) and definitely were second-rate Powers. They just did not have the money to re-equip, so they did the next-best-thing: shortened all those old rifles, reamed out the barrels and rechambered for a new cartridge which required reaming the chamber large enough to get rid of any rust which might have been in there. The new bullet diameter was to be .330" rather than .323", weight was to be 208 rather than 244 grains and a Boat-Tailed design was adopted to extend range.
Trade-Ex has FMJ AND sporting bullets and brass, LEE makes dies (about $40 and they work okay: RCBS are more than double). To keep muzzle-flash and NOISE to a bearable level, load with the quickest powder you can get away with. These are a bit of a cannon, but they WILL drop your Moose (and likely gut, skin and quarter him with the same round!) if you hit him.
These are an excellent if little-known rifle, solid, reliable and very tough. Featuring Steyr quality workmanship on the best Poldi steel, they were the final straight-pull design to come from the Ritter Ferdinand von Mannlicher.
There: I have told you what little I know. Go blast a Moose! Post a good picture of the crater! Make a stew!
Have FUN! That's what it's all about.
PS: my family used Rosses and Lee-Enfields, dirk-and-broadsword in the old days.