Here’s something you might find interesting.
100mm 3BM-8 APDS penetration calculated using demarre and using 17 pounder APDS as reference
According to ‘Сустьянцев Колмаков Боевые машины уралвагонзавода танки Т-54 Т-55’
The penetration is
290mm @ 1900m at 0 degrees
~80mm @ 1900m at 60 degrees
I am a bit angry that 3BM-7, 8 and 11 are considered “gen 2” APDS simply because they have big nose pads.
Even from their own explanation, 3BM-7, 8 and 11 do not qualify for gen 2 slope modifiers.
It is also important to note the influence of the penetrative nose pad of the APDS shells on armor penetration. A massive nose pad made of tungsten alloys reduces the denormalization of the APDS shell in the front layers of an armor at large angles, and also helps to reduce axisymmetric forces when penetrating into an armor. But the use of a nose pad leads to an increased consumption of kinetic energy in the front layers of the armor, which is spent on its deformation.
The Russian 100 mm and 122 mm APDS rounds just have a big soft steel jacket in front of the core, not tungsten alloy. On top of that, the L28 nose pad has more than just a big tungsten nose pad. It has a double conical, blunt tip on the core, and the tungsten alloy nose pad specifically tilts to improve performance against angled armor. The Russian APDS rounds lack both of these qualities, on top of missing the tungsten alloy nose pad to begin with.
Definitive evidence for 77mm can get could very fast lol
It says the 17 pounder APDS goes only 3680 ft/s? That’s 1121.664 m/s.
3675 shows up a fair bit
Interesting.
It says 1120m/s for the 77mm on comet
I noticed, I was pointing out the speed on the 17 pounder APDS though. It says 3680 ft/s.
could potentially be an older charge maybe
Bold of you to assume Gaijin would ever not give Russian ammo entirely unreasonable buffs.
It’s just a coincidence rounds used primarily by Britain are awful whilst rounds primarily used by Russia are very good. Honest!
Not just England but also the USA. US HVAP should be using APCBC ballistics and sloping modifiers on account of it being an APCBC shell that just so happened to use a subcaliber penetrator instead of being treated as the standard arrowhead-style APCR round everyone else used.
Ballistics are not that simple.
While the 90 mm M304 HVAP has a generally similar outside shape to 90 mm M82 APCBC, it still weights a lot less, only 7.62 kg compared to 10.91 kg. This is inherent to HVAP/APCR rounds, they are precisely overall lighter so that they can reach higher speeds while using the same propellant charge.
This also means that they will lose speed faster, as even if we assume that M304 HVAP has the exact same drag force as M82 APCBC at the same speeds, Newton’s 2nd law of motion, F=m*a, tells us that the same force applied on an object with lower mass will experience greater acceleration, or in this case, greater deceleration.
In fact, this is pretty much the whole reason why APDS rounds even exist. APCR rounds have a lot of additional “useless” weight and volume that adds unnecessary drag, and therefore additional speed loss, which APDS fixes by just discarding that additional weight and volume once the round leaves the muzzle.
And also this is not the reason that APCR has poor slope modifiers. These rounds use tungsten carbide as the material for their cores which, while a dense and hard material, does make it so the core turns away from the plate when hitting angled armor. In fact, the slope modifiers that we already see in the game are based on the M93 and M304 HVAP rounds. On top of that, M93 and M304 don’t have a cap, so this wouldn’t apply either way. They just have an aluminum nose plug that holds the core in place.
And again, using APDS as an example, this is why later APDS rounds use tungsten heavy alloy instead of tungsten carbide for their cores. The first APDS rounds also use tungsten carbide and similarly have poor slope modifiers comparable to APCR.
I didn’t say anything about weight. Just that due to its shell design it should be treated for the purposes of ballistics calculations as if it were an APCBC round instead of APCR.
And if these were Russian shells that would be more than enough to qualify as a cap, especially since TM-9-1300-203, Artillery Ammunition, mentions a nose plug that is aluminum or cast iron.
Would you look at that. Are you really going to say this projectile didn’t have anything resembling a cap?
All shells are treated equally for ballistic calculations. Their ballistics depend on their weight, velocity, and Cx value (a fixed drag coefficient), and the M304 HVAP actually has a lower Cx than M82 (0.28 compared to 0.33). So in that sense there’s no complaint to be had. So long as the projectiles reach their documented speeds at difference distances, there is no issue. If you do find that M304 loses speed too fast or too quickly, make a bug report.
That it somewhat resembles a cap? You could say that. However that is besides the point of what it actually does.
I said that it does not have a cap and that is indeed true. The nose plug is made of aluminum or cast iron, but that is not a cap. The sole purpose of the nose plug is to keep the core inside the body instead of exiting through the front of the body. The body is made of aluminum, and the “windshield” is just a hollow, aluminum ballistic cap.
On a side note, bringing up Russian bias for the sake of mentioning Russian bias does good to no-one here. Specially since rounds like 85 mm BR-365P APCR have a large, completely solid aluminum ballistic cap that could be seen as a cap yet it gets the exact same slope modifiers as every other APCR round.
