Hi,
A fun gun has a few factors to consider, not in any particular order.
(1) recoil, little is better than a lot (2) cost to shoot .32 is cheap, .58 is not(3) availability of components (4) ease of loading ( .32 are more difficult in cold weather, .36 are better, .40 easier again, and so on. (5) bullet back stop .32 doesn't need much, .58 needs a lot. (6) style of rifle, a slender swamped or octagonal to round .32 or .36 is a true joy to carry ( all day ) , where as a ponderous Hawken style or heavy Jaeger is not a carry all day gun.
I am almost 71 yrs. old and most of my guns are .50 cal. and bigger, no particular reason.
My favourite plinking gun is a .45 oct. to round Bucks county long rifle. ( easier to load with fat fingers, and little recoil )
Does that help?
Fred