Were the russian APBC shells actually APCBC shells?

[Oddball_E8]

I'm engaged in a discussion about this on another forum right now and it's hard to find material about it.

Wikipedia (yeah, not the most reliable of sources) states this: "This type of munition was also designated as APBC (Armor Piercing Ballistic Capped), in reference to the Soviet version of APCBC"

And I've also heard the notion that the russian APBC shells had a flat head which acted like an APC shell.

Anybody care to enlighten me?

(oh and I'm leaving out the HE bit in the abbreviations since it has no bearing on the subject)

[DMS]

There were two AP shells for ML-20, ISU-152

BR-540B and BR-540

Last (earlier one) has a flat head, do you mean that?

[Oddball_E8]

I was referring to the 85mm shells. I must have forgotten to write that :/

But would the flat head act as an APC shell?

[DMS]

They look same

AP - 2 and 3

But would the flat head act as an APC shell?

Well, it will give additional normalisation and reduce ricochet probability, I guess.

[Oddball_E8]

Well that doesn't give me much to go on in the discussion I was having :/

[DMS]

Well that doesn't give me much to go on in the discussion I was having :/

That head does the same, that cap does - increase normalisation. (or decrease denormalisation, I would say) What is better - I don't know.

[kipanderson]

Hi,

Soviet APBC and standard design western/German APCBC are not the same thing.

Soviet APCB is a standard, near solid shell with a small HE charge in the rear. (APCBC also as a small HE charge in the rear, unless British . ) However in the case of APCB the point of the shell has been chopped off. So it is indeed “flat nose...” as oft described.

Over this “flat nose..” there is a ballistic cap rounded and shaped to cut through the air with superior aerodynamics. BTW... “pointed...” is not the best aerodynamic shape for those who may be interested. The cap is just very thin mental that collapses away when there is strike.

The difference with APCBC is that immediately in front of the “flat nose...” shell which is still there with APCBC... there is “cap..” of extra hard mental then followed by a “ballistic cap...” as with the Soviet projectiles.

The main purpose of the hardened “cap...” is to help with cracking through hardened armour.

The Soviet view was that their flat nose design was good enough against hardened armour. Remember the west and Germans were moving from pointed AP shells to APCBC. Pointed AP shells did struggle against hardened armour hence the change of design to APCBC.

The net effect of the difference between the Soviet APBC ammo and APCBC projectiles is that APCBC has better penetration against vertical plate, i.e. struck straight on at 90 degree or zero degrees depending on how you count, while Soviet APCB coped far better with strikes at an angle.

The difference can be a reasonable amount.

To illustrate. A APCBC round penetrates 140mm at 100m head on against vertical plate. A Soviet design APBC projectile may penetrate just 120mm head on against vertical plate.

However at a strike angle of 45 degrees both projectiles would have same penetration. At a strike angle of 60 degrees, say striking down the side of a tank, the Soviet APBC has a very big advantage.

So as you move from head against vertical plate to a more angled strike the advantage moves away from APCBC towards APBC.

Make your mind up at how many strikes were at what compound angle in WWII.

Given that most strikes will have been, probably anyway, at compound angle between as 25degrees and 45 degrees there was probably very little overall advantage to either side.

All the best,

Kip.

[JoMac]

OH, Master AndersonofKip, we thank you for that informative explanation.

Joe

[Michael Emrys]

The difference with APCBC is that immediately in front of the “flat nose...” shell which is still there with APCBC... there is “cap..” of extra hard mental then followed by a “ballistic cap...” as with the Soviet projectiles.

The main purpose of the hardened “cap...” is to help with cracking through hardened armour.

Okay, I'm confused. What I recall reading lo these many years ago was that the cap (not the "windshield" ballistic cap) was made of softer metal to help prevent the round from skidding off of angled armor.

Wikki says this:

A further refinement of such designs improves penetration by adding a softer metal cap to the penetrating nose giving armour-piercing, capped (APC) design. The softer cap damps the initial shock that would otherwise shatter the round.

Which is not precisely the same thing but note that it does mention the cap being of softer metal.

Michael

[DMS]

The net effect of the difference between the Soviet APBC ammo and APCBC projectiles is that APCBC has better penetration against vertical plate, i.e. struck straight on at 90 degree or zero degrees depending on how you count, while Soviet APCB coped far better with strikes at an angle.

The difference can be a reasonable amount.

To illustrate. A APCBC round penetrates 140mm at 100m head on against vertical plate. A Soviet design APBC projectile may penetrate just 120mm head on against vertical plate.

However at a strike angle of 45 degrees both projectiles would have same penetration. At a strike angle of 60 degrees, say striking down the side of a tank, the Soviet APBC has a very big advantage.

So as you move from head against vertical plate to a more angled strike the advantage moves away from APCBC towards APBC.

Make your mind up at how many strikes were at what compound angle in WWII.

Given that most strikes will have been, probably anyway, at compound angle between as 25degrees and 45 degrees there was probably very little overall advantage to either side.

All the best,

Kip.

Good illustration for that:

1200 metres, while accordinag tables 152mm shell should penetrate 140mm at 100 metres. +t/d factor.

Don't know was it BR-540 or BR-540B though...

[kipanderson]

Michael,

This may well have been the case, things were tweaked constantly.

The initial purpose of the move from simple AP to APCBC was to overcome face hardened armour. For the Brits anyway. The way the “cap...” did this was to smash the face hardening and in the process self destruct. The remaining 85% of the shell then smashed its way through the armour in the usual way.

However... what was the other problem with “pointed..” AP shells.. they handled slope/angled strikes very poorly. For obvious reasons.

The design of the “cap..” was closer to that of a flat head projectile thus increasing the performance against slope/angles when compared to simple AP.

However.. the reason why APCBC was still very much less effective against angled strikes than Soviet APBC was that the “cap...” in front of the main body of the projectile acted as a lubricant between the main body of the projectile and the sloped armour.

APCBC did deal with slope better than AP. but still far worse than APBC. At over 45 degrees strike angle APCBC falls off a cliff when compared to APBC.

There is no right answer.. some may think the better performance against near vertical plate gives advantage to APCBC even though at over 45 degrees there is a very big difference .

All fun stuff..

All the best,

Kip.