hey not nice doing storytime with no pics lol
Hex driver, 1/4" socket/bit driver, and even a Torx driver are alternatives you could try. T27 should fit in 5mm hex.Also, curse those who think it's funny to put a 5mm Allen screw down an A2 pistol grip. There is a reason I cut a slot in all of my pistol grip screws for this type: it's way easier to just grab a flathead and do things.