Those rounds in the foreground don’t seem to be “lightweight”......
I was never around artillery, couldn’t tell ya!
I commanded a M198 battalion a while ago and I was always struck by the incredible size/weight/bulk of the 155mm and its required crews, trucks, support. It just didn't seem "Marine-like" or expeditionary. Really hard to pack the things into ships or transport them and their huge footprint ashore and then to carry them any distance. Also found that emplacement required huge areas of flat ground and it took a while to get in and get ready to fire. I fought a mostly single-handed fight to get the Corps to look at smaller, faster-moving fire support which resulted in a few batteries of 120mm rifled mortars but we still have the behemoths as our main direct support system.
We have several generations of artillery leaders who stubbornly insist on mirroring the army in all things. They still can't figure out why artillery is being used less and less and that planners have difficulty accommodating the bulk and slow speed of movement associated with the 155..