Welcome to the Forum.
Most of the old CVA rifles that have Jukar marked on them were made back in the 1970's.
They were made by Ardesa in Spain and unlike the Italian guns which mark a date code when their proofed the Spanish guns have no date markings.
That makes guessing the age of your rifle just about impossible except to say it is probably between 30 and 40 years old.
Back in those days there was little if any thought given to shooting elongated bullets from these guns so the rifling is usually too slow for anything over 220 grains.
As we don't talk about the modern plastic stuff here on the forum we can still talk about lead slugs or patched roundballs.
Don't be fooled by a patched .440 diameter roundballs 128 grain weight. They are quite capable of taking deer sized game as long as the range is kept under about 80 yards.
With a 60 grain 3Fg powder load they will have a muzzle velocity of around 1720 ft/sec and unless they hit bone they will often pass completely thru a deer.
Because the .45 caliber guns start to develop some pretty high breech pressures with the larger powder loads I don't recommend going over 90 grains max. (16,200 psi breech pressure), but a 80 grain powder load of 3Fg will give a muzzle velocity of around 1770 fps with a patched roundball.
As with all muzzleloaders, accuracy is the key ingredient to a successful hunt.
Many people find that the maximum powder loads are not as accurate as the smaller loads but each gun is different. Some guns like the heavier powder loads so the only way to find out what yours likes it to shoot it for accuracy changing the powder load (and the target) every 5 shots.
By the way, many of those Spanish guns have very accurate barrels on them.
Have fun.
