There some not-to-forget notes for gunsmith of any sort:

>> There numbers of replacement parts (Stocks, Foregrips
   etc) for guns of any sort. All can be easily obtained
   over Internet.

>> There are full Conversion Kits even -- Desert Eagle .357
   can be converted into Desert Eagle .50 and so on.

>> Number of modern machineguns allow to replace its' over-
   heated barrel on a fresh one.

>> Some optical scopes and electronic sights can be combined
   into one multi-purpose aiming module.

>> Intratec TEC-9 pistol can be 'extended' to a full-auto
   variant, no sophisticated tools, minimum efforts:
   Improvised Conversion = [Tool Kit + Spring + Steel Pipe]
   They say the similar improvement is possible of:
   * Calico M-900
   * Winchester Model 1907
   * Ruger Mini-14
   * Ruger Mini-30
   * M1 Carbine
   * Dragunov SVU

>> A very simple (but not obvious) way to get full-auto in
   Beretta 93R:
   Beretta 93R Full-auto = [Rubber Band  +  Beretta 93R]

>> To get an Improvised suppressor, make an 'auger' first:
   'Auger' = [Spring  +  Duct Tape]
   Than combine it with a barrel and casing:
   Improvised suppressor = [Steel Pipe  +  'Auger'  +
       Chromium-plated steel tube + Duct Tape + Quick Glue]
