"No, like this." He removed the rifle from your hands and demonstrated. You were working on trying to disassemble and reassemble the gun quicker but you'd gotten stuck. You'd been chewed out by Solidus for exactly this reason, being reprimanded and informed that you'd be killed or abandoned by the unit for being "dead weight" if you couldn't get your act together. Afterwards your older brother had pulled you aside during your down time and worked on teaching you how to do the task faster