Deer stalking expert
Muntjac are deer and are therefore protected by the Deer Act which prohibits the use of shotguns except in very specific circumstances.
Even though its a small animal the muntjac deserves to be treated properly and to this end you should use a proper deer rifle.
In England and Wales this means at least a .240 calibre and in Scotland, where no calibre is mentioned, a bullet of at least 100 grains which effectively also means .240 minimum.
There is no close season for muntjac but general thinking is that bucks can be shot at any time but does should be shot only when visibly and heavily pregnant.
This is because they are mated again almost immediately after giving birth and will have a dependent fawn until only a month or so before the next one is born.