Step 1: Have the "Hand Loader" Perk
Step 2: Find http://fallout.wikia.com/wiki/Jules_(Fallout:_New_Vegas) and pass his two skill checks.
Step 3: have a 75 repair skill
Yes, it's worth it. Trail Carbine with the Cowboy perk and this ammo is one of the best overall weapons in the game. Short range VATS and long range sniping. Killing NPCs, geckos, Giant Radscorpians and deathclaws. A huge amount of item HPs making repairs a rare event.
Wonderfull weapon even if bugged to hell on PC. That reloading bug can be fixed with a simple mod the family pet can install.