nononono - not even remotely close to a .338. I would liken it's killing abilities to being very similar if not identical to a 20" barreled .356 or .358 Win.
Both will shoot a 250gr. bullet in the 2,000fps to 2,100fps range from the carbine barrel. The .358" bullet has the potential for greater penetration and the .357 has a size advantage with greater striking surface this also matters.

I've found the 220gr Hornady bullet to produce excellent results on 800 pound ungulates, but would prefer a 250gr. bullet, myself. I would not hesitate to shoot a moose at 200 yards with that rifle, and it will easily handle a grizzly at 10feet. I'd just rather have a .338 for that or better yet, something even bigger.

The longer bullets really impinge on case capacity due ot the 2,55" functioning length for the magazine. It might be 2.6" OAL, but that's not much help.

It is a North American ctg. for North American game. It will handle any of the medium to smaller antelope, I am sure - probably leopard (not by me). Even though it will duplicate the JDJ.375 Pistol's ballistics, it is not an elephant or buffalo gun & neither is the JDJ, IMHO.