Micro screwdrivers - usually a reasonable price - precision screwdrivers will do the job plus maybe this: http://www.ebay.co.uk/itm/DRAPER-40-Piece-Ratchet-Screwdriver-Socket-Bit-Set-DIY-comes-in-plastic-case-/270841491740?pt=LH_DefaultDomain_3&hash=item3f0f69311c
Got a nice Stanley 40 piece screwdriver set but is like £17 !!! but nigh on everything needed to strip out a gun - draper is a half decent cheaper option that nearly does most stuff
indeed but still £16 more than Poundland. Mind you I've used Bic pens to undo special bespoke bolts on GameCube's - it bloody works