@saphirekosmos Hard to say. In our reality firearms obviously are very dependent on an ammo supply, which can be a big weakness in a tough spot. So, it would be an attractive feature to be able to reload using versatile energy sources. At the same time, though, if the rifle already has a capacity of 1000 shots between reloads, it might render the issue somewhat unimportant. Getting stranded on some godforsaken planet and still being able to reload probably wasn't discussed when the government contacted the gun manufacturers.
Still, if it was possible and the dude had a 100W foldable solar panel, it wouldn't be that bad. If we assume his rifle punched with the power of a Lapua Magnum calibre snipe rifle to be able to stop those bug bastards, that is, about 6.9kJ, and the reload was only 50% efficient, it woud only take a couple of minutes to recharge a single shot. It would be worth it since he doesn't spend most of his time shooting.