While I wouldn't call .62 a girly-man calibre (my .54 bucks just like my 4" M29)
I tend to think of hand-Howitzers as being of much larger bore & carrying a ball of
close to or over 500gr.
It's quite a piece, just the same, and a charge of 65gr. 3F would likely make it bark.
My .54 uses 55gr. 3F.