We've been crunching numbers to update the spreadsheet resource, and, to summarize, the HM-38 quite literally takes more time to fire a barrage than a howitzer.
In terms of barrage completion times, the HM-38 quite literally stands out in its category.
Where 4-shell barrages from conventional mortars finish in 13-20 seconds, it takes more than twice that time to finish a 6-shell barrage. Quite literally comparable to a conventional howitzer, with none of the power or range.
Naturally, we tested the values. Assuming that the weapon to be used is both already set up, is firing in its firing cone, and that the timer only begins after the command is issued, and ends after the last shell is launched, the numbers you see are accurate, with a minor delay of <1 second due to input lag and trying to run a timer using the in-game clock (which doesn't exactly have milliseconds for us)
Stat-wise, the closest equivalent to the the HM-38's performance (in terms of AoE) is the USF Pack Howitzer.
However, the Pack Howitzer is non-doctrinal, has a longer barrage range (100 vs 120), is more accurate on said barrage and has multiple offensive utilities. It also executes its 4-shell barrage in less than half the time it takes for the HM-38 to finish its barrage, and both have the same autofire range of 80. For autofire performance the HM-38 has even worse accuracy than its barrage. Shell flight time is also shorter for the Pack Howitzer due to non-mortar trajectory.
In a way, the HM-38 can also be somewhat redeemed with its veterancy accuracy bonus, which puts its accuracy on par with the Pack Howitzer's (Which doesn't have any accuracy bonuses on vet whatsoever), however, it still retains its terrible fire rate.
For what the HM-38 is, its vet1 ability is available non-doctrinally at vet0 on the PM-41, and comparatively, with how accurate the PM-41 is (Second-most accurate mortar, after the LeiG), the HM-38's performance probably only comes from the fancy sound effect when the shell does land. There's almost no merit to getting the HM-38 if you already have a PM-41. The only thing that the HM-38 has over its competitor is the ability to fire smoke at longer distances.
In my opinion, the reload value needs to either be lowered so that it's literally not howitzer level, and hopefully, the vet1 ability will be changed to a different niche. That or a different rework entirely.
Thoughts?
The sheet where I got the images from is currently labeled Sheet12 in the spreadsheet I shared in a different thread. The primary contributor wants to add more usable numbers (along with tedious testing) before finally renaming it and considering it "released"