[fourdeuce82d]

If you compare the relative volumes (taking the cube of the diameters to approximate the mass and volume of the projectile) it is 1.50 to 1.

Impeccable reasoning & calculation...shot down by an inconsiderate reality! *grin*

it would seem like that should be the case, but it's not- the 120 mm rounds are about 30 lbs, the 4.2" are ~26. The thing is, the two rounds are shaped differently- the 120s taper back to a fin assembly, whereas the 107/4.2" rounds look like artillery rounds with a small tube sticking out the bottom to hold the "cheese charge" propellant.

IIRC, some 120mm rounds actually have less explosive filler than the 'deuce. But the greater diameter of the 120s, plus their lack of spin, would be an advantage if you wanted to use them to deliver a shaped charge warhead.

[neverdem]

How timely, I was just about to ping you. Check out the links in comments# 55 & 61, especially the links within 55. Here's a link you might like:

http://riv.co.nz/rnza/hist/mortar/mort17.htm

[edwin hubble]

"Impeccable reasoning & calculation...shot down by an inconsiderate reality! *grin* "

Thanks.

It was a long time ago, but I have dropped rounds down the 4.2" mortar tube (Quantico, 1966).
I haven't ever seen a 120 round.
Semper Fi.