You're going to be an idiot to officers regardless of what you do, because the military's still classist as fuck, even in intelligence.

If you really want to become good at the type of shooting you'll need for qualifications, any accurate .22 rimfire rifle will get you there (e.g. CZ 457 and some of the Savage rifles are nice). If you want to actually be good in case you get sent to a brigade combat team and get sent out for whatever they're calling COISTs these days and you don't want to get their people killed if you have to be one of the people making entry on houses and shit - assuming you're gonna be a regular ol' all source analyst here based on your three year contract - pick up a halfway decent AR15 and dryfire the thing for five or ten minutes a day doing the types of drills you'll find in Ben Stoeger's Dryfire Reloaded, except because you're doing them with a rifle you should scale the targets back way further. But that route is exceedingly rare for all source dudes and dudettes, along with SIGINT analysts. More common for HUMINTers and cryptologic linguists in th'Army side of the house, especially if they've shown the maneuver element that they're not total dogshit and can pull security and can actually help them do what they want to do without taking as many casualties.