Gun Technical Data

French Guns

Notes:

1. TR means "Tir Rapide" or "rapid fire". Sometimes called TRP after the manufacturer Puteaux.
2. The Germans liked this gun and prodiced their own Pzgr.40 APCR for it. Care should be taken not to confuse this with the original French shells.
3. This was an anti-aircraft gun (CA=contre-aéroplanes). It was however used in a dual role against both air and ground targets by the Mobile Anti-Tank Batteries (BACA).
4. Sources differ.

Armour Penetration Overview

To be useful, armour penetration figures should specify not only the gun, range and penetration achieved, but also the ammunition fired, the angle of impact, the type of armour attacked and the penetration criterion used. 

The customary angle of impact when quoting penetration performance is 30º from the vertical (i.e. 60º from the horizontal). The French and British measure angle from the vertical, the Germans and NATO measure angles from the horizontal. It is also traditional to quote penetration against homogenous armour. Performance against face hardened plate, especially for smaller weapons firing uncapped rounds, can differ greatly. Homogenous armour plate has the same density and hardness all the way through, face harden armour has had its outside hardened or carburised.

The Germans generally tested against Homogenous Armour Plate at 30º from the vertical. Luckily for us, in 1941, the German Design Office (Wa Pruef) tested the armour piercing penetration of many French guns using their own criterion. For this reason, I have quoted the German designation of the French guns in the table above.

The French had figures for their own guns, but the rarely seem to standardise on an angle (25º, 30º or 35º) and usually use 400m which is never used by the Germans.

A table for rough conversions from sloped armour to an equivalent thickness of vertical plate is given in WO 185/118; well-sloped armour being more effective than would be indicated by a simple cosine calculation. 

Penetration tables also take no account of non-penetrating damage. The running gear of all vehicles can be vulnerable to AP or HE fire from nearly all calibres; in fact the German 37mm gunners speciallised in firing at the tracks of the heavily armoured French tanks. Extremely large calibre rounds can cause catastrophic damage without needing to penetrate the target; a 155mm shell, for example, might completely remove the turret of its target. 

Germany began using welded construction in the 1930s and France used cast armour. Riviting was still used in many British tanks as well as a few German and French tanks such as the Panzer 38(t), the AMR 33 and the hull but not turret of the B1 bis. A shot hitting an exposed rivet-head could cause the rivet shank to break off and be projected into the tank, causing damage.

The following table can be used to convert penetration values for shell sizes vs different angles of impact from the vertical:

Armour Penetration - French Guns

The following table shows a comparison of muzzle velocity (in m/s), angle of impact from the vertical and armour penetration (in mm) from different sources.

Notes:

1. The Obus perforant AL (Allongé Lefèvre) Mle 1916 (APHE) shell was heavier than the earlier Obus de rupture Mle 1910M. It contained 350g of HE instead of 90g. However this did not seem to improve its performance as might be expected. The mle 18 had 325g of HE.

Comparision between French/German/British Guns

The following table shows a comparison of muzzle velocity (in m/s) and armour penetration (in mm) against homogenous armour plate at a 30° angle of impact from the vertical for the guns used in the France 40 campaign.

Country	Gun	Ammo	m/s	100m	500m	1000m	1500m	2000m
	MG 34	SmK	785	8	3
		SmKH [1]	785	13	8
	7,5mm MAC mle.31	AP mle 29	805	6
	12.7mm Vickers	AP	785	15	9
	13,2mm Hotchkiss	AP mle 35	800	12	8
	15mm BESA	AP	884	20	15
	Panzerbüchse 39	SmKH	1265	34	14
	Boys Mk.I	Kynoch AP	990	21	11
	2 cm KwK 30 & 38	Pzgr	780	20	14	9
	25 SA 35	AP mle 34 charge forte	950	35	30	20
	25 SA 34 or SA-L 37	AP mle 34 charge normal	920	35	30	20
	25 CA 39	AP	875	30	25	15
	3,7cm KwK 36 3,7cm PaK 35/36	Pzgr	745	35	29	22	20
		Pzgr.40 [2]	1020	64	31
	3,7 cm KwK 34 (t)	Pzgr.(t)	675	35	30	23	21
	3,7 cm KwK 38 (t)	Pzgr.(t)	741	36	31	25	22
	37 mle 16 TR 37 SA 18 37 SA 17	APHE mle 92 m 24	388	12	8
	37 mle 16 TR 37 SA 18 37 SA 18 mle 37	APC mle 35	600	25	19
	37 SA 38	APC mle 38	705	29	23	16	12
	2pdr OQF Mk.IX	AP	808	66	50	35	25
	4.7cm Pak(t)	Pzgr.36(t)	775	54	48	41	35
	47 SA 35	APC mle 35	660	39	33	26	20
	47 SA 37	APCBC mle 36	855	57	50	42	36
	7,5 cm KwK 40	K Gr rot Pz	385	41	38	35	32	30
		Gr38 H1/A [3]	450	70	70	70	70
	7,5 cm leIG 18	IGr 38 H1 [3]	305	45	45	45	45
	75 mle 1897	APHE mle 10M	580	51	47	43	39	36
	75 SA 35	APHE mle 10M	470	41	38	35	32	30
	25pdr OQF Mk.I	AP-T	610	82	60	41	28
	8,8cm FlaK 18 & 37	Pzgr.39	773	120	110	100	91	84
	10,5cm leFH 18	Pzgr	470	63	59	54	50	46
		Gr39 H1/A [3]	470	80	80	80	80
	15cm sIG 33	Gr39 H1/A [3]	280	160	160	160	160
	15cm sFH 13	Gr39 H1/A [3]	460	160	160	160	160
	15cm sFH 18	Gr39 H1/A [3]	465	160	160	160	160

1. The SmKH was a very rare (less than 2%) bullet with a hardened core of tungsten. It was available until 1942 when lack of tungsten stopped its production. The Panzer I seems to have been give priority as it was expected to meet enemy tanks; it had 94 SmKH and 2100 SmK rounds (i.e. approx 5%).
2. The only Pzgr.40 (APCR) shells produced in 1940 were for the 3,7cm L/45 KwK36 or the 3,7cm PaK 35/36 which were equipped with a very small number during the battle of France. Reports by OKW show that 7,440 Pzgr.40 rounds were fired out of a total of about 70,000 (i.e. approx 10%). The 4,7cm Pak(t) on the Panzerjäger I received the Pzgr.40 only in July 1940, the 2cm Pzgr.40 was not introduced until later in the year and the other Pzgr.40, such as the 3,7cm(t), in May 1941: i.e. in time for the Russian campaign. 
3. The German GR H1 shells are HEAT. This explains why armour penetration does not drop off with range. HEAT peretration is not usually quoted over 1500m. The HEAT shells quoted here are those in use in 1940, HEAT shells improved during the war.