[dingaling]

Even the hallowed 'automatic sear' is just an arrangement of small metal shapes and springs. The annual volumes of Jane's Infantry Weapons used to have diagrams and detailed descriptions of the sears' operation. It's only penalties of law that prevents people making or distributing them, not complexity or wizardry.

On the other hand the majority of NATO training emphasises rapid single shots, with bursts only for initiating ambush or breaking contact ( and usually only when authorised by the NCO ). Being limited to single-shot isn't therefore too much of a restriction.