The RM-40 is the 2nd USSR mortar. It unlocks at the end of tier 3 on the research tree and counts as BR III.
It has no stat advantages over the BR I RM-38.
And yet this mortar uptiers you in matchmaking, costs several days worth of playtime to unlock, and 6x as much silver as the RM-38.
This weapon needs some redeeming qualities at least. And we can assume that these qualities will not be attributed to the mortar itself for historical accuracy, so my suggestion is unlock a new squad with better soldier unlocks together with this mortar.
The RM-40 squad uses the same upgrade tree as the RM-38 squad, with the following changes:
The 3rd “+25% of squad experience” node adds a branch that unlocks +1 assaulter, sniper or engineer
The 4th and last “+25% of squad experience” node replaces its unlock branch with +1 mortarman or MG gunner
Actually its RPM is not 60 as stat shows
The rpm of RM40 is the level of ordinary 50mm mortar
RM38 is a slower 80mm mortar level
You can refer to my test results
Yes, I agree the RM-40 fires a little faster. Though that only really makes a difference at the start of the match where you need to fire quickly to cover all possible enemy routes from the spawn.
During a match, you find good mortar targets too infrequently to make use of the fire rate - especially on the densely obstructed parts of several USSR/Wehr maps. I don’t think that alone is an outstanding trait of the RM- 40 (and I do have one since you’re forced to unlock one to unlock the research after it) and it needs more to be a resource of its own right.