Needing another 120mm mortar for a Motor Rifle Battalion, I set about this 82mm(?) from a cheap Chinese-made set. Having removed the bipod I 'sharpened' the end of the barrel and added a length of plastic tube.
A new bipod was made by bending a bit of brass tube which was then drilled into the mdf base.
Behold the ensemble - and indeed the tools which were used in it's creation! I know the barrel is way too long for a 120mm, but as they say in the Forbodian Peoples' Army "if you're going to have a mortar, have a big 'un!" That probably sounds better in the original Forbodian.