What we're probably not seeing is the velocity / charge stack for each set of rounds. So less than LOS even, nowhere near the 1.6x mm suggested by WW2B. The dip at 45° suggest less force is needed to go through an x mm plate than through a 1.41x mm plate at 0°. Question: WWII Ballistics: Armor & Gunnery Post by Tarrif, 21:20 I just found my old copy of 'WWII Ballistics: Armor & Gunnery' by Lorrin Rexford Bird and Robert Livingston (Overmatch Press 2001) which is held in fairly high regard for its penetration data. The curve having a dip at 45-degrees makes sense, because you'd expect that the thicker the steel and the more slope, the less penetration. What I think they're looking at there is partial versus full penetrations.į seems to show the force needed, or the velocity needed to penetrate.Īnything above 1 is a full penetration that maybe tumbled?Ībove 1? F seems to be numbered in tens of thousands. Well, yes, why would it give us the thickness? We can determine the thickness from the provided e/d (T/D ratio) given the shell used (3'). The M5 was issued exclusively to the US Armytank destroyer battalions starting in 1943. The gun combined a 3-inch (76.2 mm) barrel of the anti-aircraft gun T9 and elements of the 105 mm howitzer M2. It's just the ratio thickness of the hole and the penetrator. The 3 inch Gun M5 was an anti-tank gun developed in the United States during World War II. Not sure where else to ask.į (e/d,0) doesn't give us the thickness of the RHA (rolled homogenous armor the standard used for armor testing and production). I'm not sure what to make of this, so I'm hoping that maybe someone here has researched the topic a bit more and can help me understand it better. But Fig.2 from AD309986 suggests that with these parameters, the plate would perform worse than the equivalent thickness at 0°, so somewhere under 1.41. A rough estimate based on the WW2B charts suggests a modifier of around 1.6 instead. LOS for 45° would be 1.41 times the thickness at 0°. The M72 was replaced by the 6.63 kg (14.62 lb) M61 armor-piercing ballistic capped high explosive with tracer (APCBC-HE-T) shell. I took one example, a T/D ratio of 0.5 and 45°. Here's a chart I took from it with some comments by me: EDIT: chart context It looks at the penetrative capabilities of the 3' M79 AP projectile against various T/D ratios and slopes. However, I've since been show a declassified study on slope multipliers done by the US army (I assume at around the time of the war or shortly after, its code is AD309986 for whoever is interested) and it contradicts WW2B. These two charts from WW2B defined a lot of my assumptions for a while: I've been following the math in WW2 Ballistics: Armor and Gunnery for a while now, particularly that for slope multipliers and how against certain T/D ratios, some sloped armour plates offered significantly more effective protection that LOS would imply (for example, 100mm at 60° could offer up to 300mm worth of protection instead of just 200mm).

Hopefully this isn't too technical a question for this sub.

Wwii ballistics armor and gunnery