Russian and U.S. Uncapped AP Performance

[rexford]

When we did the background research for our book, we did not have access to Internet and assumed Russian uncapped AP would penetrate about 10% less than Allied rounds.

The 122mm APHE round at 2600 fps would penetrate, by DeMarre from U.S. 75mm M72 AP (solid shot), 257mm if it were exactly the same as M72. Multiply by 0.88 for HE burster in 122mm APHE, for 226mm. Multiply by 0.87 for "quality" relative to M72, to obtain 197mm penetration.

Russian Battlefield figures for 122mm AP converted to 50% success result in 173mm penetration at around 2600 fps, 173/226 results in 0.77 "quality" multiplier.

Above analysis suggests that Russian AP penetrates about 23% less than Allied AP, after adjustment for HE bursters. Russian projectiles had lower nose and shoulder hardness than Allied uncapped AP, which appears to account for some of the difference. Differences in projectile metallurgy may also be a factor.

Interesting aspect of figures on Russian Battlefield, which are similar to those presented by Vasiliy Fofanov on Yahoo!Tankers site, is superior penetration of blunt nose APBC compared to uncapped AP.

Russian 122mm uncapped AP penetrates about 173mm at 0m and 0 degrees when data is extrapolated, 122mm APBC penetrates about 206mm under same conditions. Russian Battlefield has a curve where 122mm APBC penetrates over 210mm at point blank

See: http://www.battlefield.ru/library/archives/weapons/weapons6.html

Russian Battlefield figure for 85mm AP at 0m/0 degrees is about 125mm extrapolated, prediction from 122mm APBC data and curve on Russian Battlefield shows about 144mm for 85mm APBC.

The above suggests that APBC could significantly outpenetrate uncapped AP rounds, which is not what we would have expected (standard rule of thumb gives sharp noses better penetration performance at low angle than blunt nose). The "battering ram" appears to be better than the lance, at times, when it comes to defeat of thick armor (and castle doors).

Lorrin

[Croda]

:eek:

[Grisha]

Very interesting. Thanks, rexford.

[Redwolf]

Shouldn't this be heavily angle-dependent?

If they are that bad, I would assume they break up even more under very low angles, but less difference to better AP for moderate angles.

[Foreigner]

AFAIK, blunt-nosed AP rounds have a lower tendency to ricochet from sloped armor - the cap "anchors" when it touches the armor and helps "turn" the round closer to meeting the armor plate "head-on".

Also, nose caps were made of softer metal covering an extremely hard and sharp core tip. For whatever reason having a thin layer of soft metal between the striking core and the armor plate increased penetration ability (IIRC, the theory goes that in the microseconds after the cap first touches the armor, during which time the core goes through the soft cap, the heat generated in the process is enough to warm up and "soften" the tiny spot on the armor plate where the core utlimately strikes).

[Redwolf]

Originally posted by Foreigner:

AFAIK, blunt-nosed AP rounds have a lower tendency to ricochet from sloped armor - the cap "anchors" when it touches the armor and helps "turn" the round closer to meeting the armor plate "head-on".

Yes, that is not contrary to what I implied and asked about.

I meant that for very low angles (unsloped) the bad effect of bad uncapped shells must be worse than for medium sloped hits.

[kipanderson]

Rexford, hi,

Yup, it is interesting that the Soviet APBC round does, indeed, appear to be quite affective overall. When discussing the Soviet APBC rounds it must always be remembered that they far out-perform western/German APCBC rounds against sloped or angled armour. Given how often strikes will have been at a compound angle greater then, say, 40 degrees on a real battlefield, the Soviet APBC design was not too bad. Given that it is likely have been a lot cheaper too, for obvious reasons.

All the best,

Kip.

PS. Everyone always talks about the graphics in CMBB, and I too am greatly looking forward to them. However, one of the biggest challenges for Charles will be to get the modelling of Soviet APBC rounds correct. They are very different from German APCBC rounds. He will have to do a lot of tweaking of the penetration equation. However, I am 100% confident Charles will have done this. However, there is nothing easy about it.

[ March 09, 2002, 06:40 AM: Message edited by: kipanderson ]