Seen metal selector plate on a D-Boys PDW v2 box
& think I've seen a metal selector on a micro switch v2 box
But tappet plate ???
more weight - slower return/chamber
more hammering at gearbox front (increase of cracking)
Selector plates do break but tappet plates normally just wear at fin
Only broke one M4 selector refitting back in receiver
and heard/told selector on G36's are easy to break too if not careful
If you have a Cyma v2 box they have a clear tappet plate which is quite hard/brittle
(Cyma v3's have a white more flexible tappet)
Guess these clear cyma v2 tappets can break if you are not careful
(or if you tread on one)
They have a cut out up or taper up front, due to internal strengthening - so a tiny mod req
(nothing major)
But think you have to go some to bust a tappet unless really unlucky me thinks