Shortround6
Major General
Effective in what way?
15mm simply describes the diameter of the projectile. Not it's weight or velocity. The German 15 X 96mm round (15mm dia projectile and 96mm case length) was rather high velocity but while bigger than a 12.7mm/.50 cal bullet it was quite a bit lighter than a 20mm Projectile.
From Tony Williams most excellent website. BOOKS BY ANTHONY G WILLIAMS
The AP projectile went about 72 grams at 850 m/s but the HE only weighed about 57 grams compared to most 20mm HE projectiles going about 95-130 grams with HE content to match.
Against unprotected troops a solid bullet is pretty much a solid bullet (dead is dead), against trucks, parked aircraft, small boats (small meaning fishing trawlers, motor torpedo boats and landing craft), trains and even small buildings the 20mm HE is going to more effective. Against armored vehicles the 15mm may be more effective against light armor ( light tanks, armored cars, APCs and SP artillery.) 25-30 ton tanks are NOT going to be taken out by 15-20mm aircraft cannon except by lucky hits.
The 15mm AP round is more effective than some 20mm ammo and less effective than others.
15-20mm AP ammo isn't really much good against concrete bunkers or even heavy old stone buildings.
15mm simply describes the diameter of the projectile. Not it's weight or velocity. The German 15 X 96mm round (15mm dia projectile and 96mm case length) was rather high velocity but while bigger than a 12.7mm/.50 cal bullet it was quite a bit lighter than a 20mm Projectile.
From Tony Williams most excellent website. BOOKS BY ANTHONY G WILLIAMS
The AP projectile went about 72 grams at 850 m/s but the HE only weighed about 57 grams compared to most 20mm HE projectiles going about 95-130 grams with HE content to match.
Against unprotected troops a solid bullet is pretty much a solid bullet (dead is dead), against trucks, parked aircraft, small boats (small meaning fishing trawlers, motor torpedo boats and landing craft), trains and even small buildings the 20mm HE is going to more effective. Against armored vehicles the 15mm may be more effective against light armor ( light tanks, armored cars, APCs and SP artillery.) 25-30 ton tanks are NOT going to be taken out by 15-20mm aircraft cannon except by lucky hits.
The 15mm AP round is more effective than some 20mm ammo and less effective than others.
15-20mm AP ammo isn't really much good against concrete bunkers or even heavy old stone buildings.