Such issue was first pointed out two days ago when I posted the datamined results of Gaijin’s slope effect modifiers on a Chinese WT forum. Commenters below my post quickly noticed that the APDS shots have a sketchy penalty curve. To understand such issue, we must first have a look inside Gaijin Entertainment LLC’s black magic of how their slope modifiers work: Here are some extracted codes from damagemodel.blk:
"slopeEffect0deg": [0.0,20.0], "slopeEffect5deg": [5.0,17.0], "slopeEffect10deg": [10.0,15.0], "slopeEffect15deg": [15.0,10.24], "slopeEffect20deg": [20.0,7.2], "slopeEffect25deg": [25.0,3.72], "slopeEffect29deg": [29.0,2.76], "slopeEffect30deg": [30.0,2.46], "slopeEffect35deg": [35.0,2.24], "slopeEffect40deg": [40.0,2.064], "slopeEffect45deg": [45.0,1.8], "slopeEffect50deg": [50.0,1.4], "slopeEffect55deg": [55.0,1.2], "slopeEffect60deg": [60.0,1.024], "slopeEffect65deg": [65.0,1.0], "slopeEffect70deg": [70.0,1.0], "slopeEffect75deg": [75.0,1.0], "slopeEffect80deg": [80.0,1.0], "slopeEffect85deg": [85.0,1.0], "slopeEffect90deg": [90.0,1.0]
The [X, Y] values in the brackets are where magic happens: X value determines the angle of the armor (0 degrees meant that the shell is parallel to the armor plate, while 90 degrees indicate a perfectly flat plate. This value basically means how many degrees off from parallel is the shell with the plate.), while the Y value determines the penetration penalty to such slope. For example, an APDS shot undergoes a penetration decay of 2.46 times when it hits a plate that’s angled 60 degrees, or 30 degrees away from the parallel position. Pretty logical, huh? Let’s see it in action.
For example, the 10m penetration of Royal Ordnance L7’s DM13 APDS at a vertical plate (90 degrees against the angle of incidence, 0 degrees construction slope) is 303mm. At 30 degrees against the AoI, such calculation kicks in:
The shell undergoes a penetration decay of 2.46 times as stated before, therefore, DM13 APDS can penetrate 303÷2.46=123mm of rolled homogeneous armor angled at 30 degrees from 10m away. Pretty logical, eh? Not when the shell hits it one degree off. In actual combat, the angle will vary due to suspension, terrain, ballistic curves of the shot, and most importantly, angling. Therefore, it’s extremely rare that one can penetrate a perfectly 60 degrees armor plate. T-54, for example, has a UFP of 100mm with a construction angle of 60 degrees, which equals to 30 degrees against the AoI. According to the stat card above, DM13 APDS can penetrate such plate all the way up to 2km away, a historical figure that has multiple real-life examples to back it up. It all looks “historical”, right? Wrong. What Gaijin did not show, is what happens to the slope penalty after 30 degrees AoI. Most shells in the game have a subtle curve that goes up by 5 degrees, but APDS is an exception. After 30 degrees AoI, we find an extra entry in the code:
Yes, just one degree off, and your penetration penalty increases from 2.46 times to 2.76 times! That means if a T-54 angles itself for only one degree, your L7’s APDS would have just barely penetrated it from 1km away. At 1.5km, it can only eat through 93mm out of the 100mm found on typical Soviet armor.
Right after 30 degrees AoI, the curve took a sharp turn and heads toward the eternity of Russian Bias. At 25 degrees AoI (Which happened to be a construction angle of 65 degrees, also typical on Russian tanks like IS-6), the penalty skyrockets to 3.72 times. When facing IS-6’s 100mm UFP angled at 25 degrees AoI, its penetration dropped to a whopping 81.5mm. Yes, a post-war shell designed to kill T-54s from 2km away, cannot penetrate an abandoned tank project in the forties! Ironic enough, Gaijin introduced this mechanism in 2015, with the hope of bringing more realism to the game, while denying the most basic historical facts that players submitted in bug reports for three times in 2015 and 2017, all proving this BS penetration curve is wrongfully wrong! Gameplaywise, the heaviest users of APDS are everyone but USSR, while the nation with mostly thick, 60-65deg UFPs are—you guessed it, USSR. So, I posted it on the WT subreddit, backed by the calculations done by the Chinese forum users (Asian math, da) and the confirmation of a well-known dataminer, u/_mike10d. In just one day, my post gained 400+ upvotes and nearly 300 comments, with the community outrage that was about to be brought to the game’s official forum. The forum post currently has 6 pages of discussion.