Can't tell you much that isn't obvious. Inexpensive SxS made in Spain with 3" chambers and a Greener crossbolt action. Should be safe with all modern shells BUT (the big butt), it will kick like crazy with 3" magnums because it is relatively light AND it probably wasn't made for steel shot. Shooting steel in it isn't dangerous per se but if it has tight chokes as many Spanish doubles do, it may peen and bulge the choke area,especially in the left barrel, which is usually the tighter choke.
The chokes are marked on the barrels in mm. of constriction ("Choke 15.1" etc) but I don't know how to translate that into American chokes. Somebody here or at
www.doublegunshop.com/BBS should be able to tell you that, and also the reputation/value of Loyola doubles. I have heard of them, but know little. Is there an importer's marking on the barrels? Should be, and that will tell you a little more.
Clearer shots of the markings on the barrel flats and water table of the receiver would tell us more. I'll look up the date-of-proof code (M1) and let you know when it was made.
Edit: it was made in 1967.
Looks like a nice little Spanish bird gun!