Nothing like an 8" howitzer. When I was in R&D at Sill, working on the cannon launched guided projectile (copperhead) and the designators for it, the motivating idea was said originally to have been combine the accuracy of a well-registered 8" howitzer with a moving target.... I have actually seen demonstration batteries put an 8" inert round in a 1 m by 1 m window at 10k (admittedly with a fresh met, 1st order survey, absolutely accurate powder lot information and temperature and a fresh registration, but still....). An old brownshoe guy told me that in the '40s they put them into the blockhouse on Signal Mtn.