Soviet Flat Nosed AP Ordnance

[Jeff Duquette]

Soviet Flat Nosed AP Ordnance

The following bit of information seems to explain the Soviet logic behind flat nosed APBC ammunition. It also implies that the flat nose was acting de facto as a low grade armored piercing cap with flat areas shearing away during perforation along pre-cut scribes in the penetrator.

From: Records of Foreign Weapons and Equipment, Volume I, U.S.S.R. Generated by the British Army right after WWII. This is a fairly voluminous work (some 700 pages all totaled I think) on Red Army Weapons and Ammunition. Fairly rare.

<BLOCKQUOTE>quote:</font><HR>Armour Piercing projectiles are used with and without ballistic caps and are of the solid type as well as with an H.E. content. Penetrative caps are not now used, but the Russians favour machining circumferential grooves, generally two, on the ogive so that the head will break away leaving the remainder of the projectile undamaged. This gives a penetrative cap action and prevents shattering of the projectile at the higher velocities. Arrowhead Composite Rigid Armour Piercing Projectiles are also used. These are considered to be of inferior design. Although they provide increased penetration at short ranges their ballistic shape is so poor that they quickly lose their high muzzle velocity and are considered useless above a range of 1000 metres, and for the small calibre 1+5 mm, maximum range is considered as being 500 metres.<HR></BLOCKQUOTE>

[Stalin's Organ]

This looks a bit odd. The profiles I've seen of Sov flat-nosed ammo are nothing like thus - they really do have quite a flat nose, with a ballistic cap.

I wonder if this might have been a "field mod" done to some ammo, or possibly just poorly manufactured ammo that happened to behave like this, or even a modification that the Sov's did to some or all of their "standard profile" ammo to get the effect?

[ 07-18-2001: Message edited by: Stalin's Organ ]

[Grisha]

Amazing solution, and so typically Russian

[Jeff Duquette]

yes quite simple...yet quite brilliant.

[rexford]

Jeff,

Thanks for posting that info from British report. The Russian AP grooves and the part about the nose falling off to improve angled penetration is a new one for us, and may account for some battlefield results.

The grooves in the APBC ammo seem to be there to hold the ballistic windscreen cap, where it is crimped into place. See special notes in our book after page 63, the 76.2mm APBC drawing where the ballistic cap joins the main body of APBC.

The part about the nose falling off on an angled hit to improve penetration seems to be about the uncapped AP round with a pointed nose even though the report does not state that fact.

The amazing thing about the report is that they don't mention the flat nose on APBC, and miss the extremely low slope effects which greatly improve penetration on angled hits.

The British had 76.2mm APBC ammo during the war (came with T34 and KV-I they were sent), they shot it against 0° slope armor and reported results, yet nothing in that report Jeff obtained on magnificant slope effects.

76.2mm APBC fired at 680 m/s could penetrate almost as much 60° armor at 500m as German 75mm APCBC fired at 750 m/s. But at 0° impact German 75mm outpenetrates Russian 76.2 by 123mm to 75mm.

Flat noses buy excellent penetration at angles but kill the effectiveness when target impact has small angle.

Russian Battlefield indicates that Russian 122mm AP (one with grooves so nose leaves round, leaving it "flat nosed") could not penetrate Panther glacis during initial combat. Then it penetrated at about 650m.

Finally, late 1944 found 122mm AP shattering a Panther glacis at 2500m!!!

[ 07-19-2001: Message edited by: rexford ]

[ 07-19-2001: Message edited by: rexford ]

[rexford]

In British test, German 75mm APCBC penetrated 37% more armor at 610 m/s than Russian 76.2mm APBC at 0° impact. Difference is due to nose hardness (German at 61 Rockwell C, Russian at 52), projectile weight (German round a little heavier) and nose shape.

[Jeff Duquette]

Rex:

The prefab-grooves are not the windscreen crimp grooves. These are breakaway grooves cut further down on the penetrator well below where the ballistic cap is attached. I just received some additional information from a completely different source in Austria. I will send along some of these images this afternoon as I am just headed out the door to work (gulag).

The thing that kept bugging me was the similarity in appearance between the tip of a Soviet mono-bloc APBC penetrator and a two-piece US, British or German APCBC penetrator plus penetrator cap. Again I will send along some additional info to you this evening. I may have also found a more solid lead on Soviet firing tables for 76.2 and 85mm. Hopefully this may in turn lead to some more in depth ballistic test reports as well.

[ 07-19-2001: Message edited by: Jeff Duquette ]

[rexford]

Since APBC already has a flat nose why would one want to have the nose break off to provide a flat nose?

The remainder of the round would not have enough mass left to do much of anything after the forward part broke off and bounced away.

Are the grooves you are looking at for the rotating bands?

A fellow in Australia noted that uncapped Russian AP may have had grooves to knock off the pointed nose on impact, producing a quasi-flat head round.

[Jeff Duquette]

APCR and HVAP rounds mass is quite small relative to the entire round. In addition both HVAP, APCR and SABOT lose significant portions of the projectile either during barrel exit or upon impact\perforation. Velocity is squared. Mass is just mass.

As far as it going from flat to flat...I'm not sure what you mean. My impression was that a longitudinal fracture was implied (parellel to long axis of pentrator..along nose) not a fracture perpendicular to long axis of penetrator. Analogous to petals shearing away from APCR or HVAP. At least that is the way I read the passage of interest.

And no these features are clearly not the bourrelett or the rotating band either. See images I sent over.

[ 07-20-2001: Message edited by: Jeff Duquette ]

[rexford]

Thanks Jeff.

Flat nose APBC apparently had break-off grooves just below the flat nose that would remove the nose in case of violent impact, such as a high angle hit or face-hardened armor at an angle.

In effect, this would act like a quasi-armor piercing cap where the initial damage upon impacyt is limited to a "throw away" armor cap and the main body would then be in perfect shape to pound the plate.

This break-away tendency would probably boost the penetration ability against face-hardened armor on angled hits, but might do little on hits at vertical angles.

The identification of the break-away grooves is a major find and I thank you for bringing this to our attention.

Lorrin