[FreedomPoster]

>>Is a 20mm projectile as fast as a 105mm round???

Probably faster. Hmmm.

I Googled a table that claims 3500 fps for the 20mm. I can't imagine a 105 is anything nearly as high.

[Cannoneer No. 4]

3380 fps for 20mm M56 HEI. Several sites I have searched give 105mm howitzer velocities between 400 and 600 meters per second. I am not sure which gunship took this footage. AC-130H Spectres have 20mm, the AC-130U Spooky II has 25mm.