FYI: Penetration Mechanics

I put some of these in this thread and I figured they were largely common knowledge, but apparently this isn't the case because I keep seeing people get them wrong over and over and over again.

• APCR does not necessarily have less penetration dropoff over range than AP. In many cases the opposite is true. Penetration dropoff stats are readily available in tanks.gg and in the game itself, they are easy to look up.
• APCR is not more likely to autoricochet than AP, assuming equal caliber. The 20 degree autobounce angle is a flat number that exists independently of shell normalization unless your shell caliber is more than 3x as thick as the armor. In other words, autobounce angle is 20 degrees for both AP and APCR, it's not some deal where it's 18 degrees for APCR and 15 degrees for AP because APCR has 2 degrees of normalization and AP has 5. This is why 90mm guns still bounce off the STRV S1 even though the bonus to normalization from 2x overmatch would otherwise result in an angle calculation of >20 degrees.
• On the flip side: Shell normalization is still a thing for normal armor thickness calculation, which a lot of people either neglect or don't even seem to know about in the first place. 340mm HEAT is not meaningfully better than 326mm APCR for penetrating non-autobounce armor in most conditions, and it suffers considerably when hitting spaced armor before the main hull (which tanks.gg does not accurately adjust for). In this case the 340mm pen HEAT shell's advantages are its reduced autobounce angle (5 degrees vs 20 degrees) and to a lesser extent its lack of any penetration dropoff whatsoever, but the increased nominal penetration at close range is of little practical consequence.

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