All the more reason to keep the 4.2" w/longer barrel and beefed up base plate- some experiments had the old warhouse plunking rounds in at +10 klicks. It's jeep portable, packs a punch...and without fail that particular weapon system somehow attracts the best, the brightest, and the most handsome of all military personell. Don't why that's so...but it's true.
(creaking noises as a fat ex mortar maggot tries to pat himself on the back...)
By all means, give the infantry all the mortars they can take with them. But when things get busy, there's nothing like having some 155mm tube artillery to really take care of business.