I was in the first pilot program for Marine non-NCO’s to be trained for an M110 Self Propelled ( 8 inch )crew.
I have no idea how that program turned out.
I was in an engineer battalion at Ft. Hood in the mid 70s and we used to ride the tank trails (in M-113s) all over the place.
I felt the most sorry for those poor bastards who had to ride the M110s out in their exposed tractor seats in the dust and rain. Hopefully life went uphill for them after they ETSed.
8 inch guns are badass, though. (175s as well).