47mm 47/32 and tank gun EP (effeto pronto)

Webmaster

Administrator
Staff member
Posted 22 August 2003 by Eduardo

I've read that Italian 47mm were also provided with EP rounds. It surprises me. It's that true. When they started to be used by Italian units in the field.

Does anybody know its performance and availability?


Thank you.


Eduard
------------------
Posted 23 August 2003 by SM79Sparviero

Effetto Pronto 47 mm shells were available but the gunners soon realized they were much worse than usual 47 mm kinetic armour piercing shells.
EP is an hollow-charge shell, or HEAT. The power of the high-temperature high speed metallic jet that pierces the armour is directly related to the diameter of the shell, a 75 mm shell from a 75/18 howitzer could easily destroy a Sherman or a Grant but a 47 mm shell is too small!

Moreover, a HEAT shell generates an effective concentrated metal dart if its terminal speed is not too high, as in a short howitzer ( 350-400 m/sec.) .The 47 /32 mm Ansaldo Italian gun was projected to shoot hard armour-piercing shells at high speed to hit a moving target as a tank ( 700 m/s and more).
I think that an EP shell would have been more useful for anti-tank fighting at low range with the small Brixia 45 mm mortar just for the low speed of its grenades.

--------------------
Posted 25 August 2003 by Eduardo

Thanks for the information.

Even though 47mm is just a little lower diameter than a bazooka. The effect vs armour should not be so different?


Ed
--------------------
Posted 25 August 2003 by SM79Sparviero

The first Bazooka launched 57 mm ( 2.75 inches) shells.It could not seem very far from a 47 mm Effetto Pronto , but the piercing power of an hollow charge jet is related to the diameter of the shell by a QUADRATIC ratio, not a linear one.That's a jet generated by a 4 cm shell is more powerful than the similar from a 3 cm shell as 16 related to 9 and not as 4 related to 3!

Moreover, a HEAT shell can create a good armour-piercing jet if the shell is not too fast and if it doesn' t revolve around its axis.It has always been a good anti-tank weapon if used at short range.
In the more powerful 88 mm bazooka the projectile's flight path was stabilized by a sheet metal stabilizer ring at the rear of its shaft looking quite similar to those used on aircraft bombs. The propellant continued to burn even after it left the tube for another 2m , the projectile had then reached its velocity of 105m/s.

The Italian 47 mm Effetto Pronto shell was stabilized by the spin around its main axis imposed by the barrel of the gun, this spin and the terminal high speed ( 700 m/sec.)of the shell increased the probability to hit a target at long range but in the same time they made an interference with the jet of the hollow charge.
According to me a 45 mm HEAT shell for the Brixia mortar would have been more useful at short range for the low speed of the shell and for the absence of a spin.
 

Webmaster

Administrator
Staff member
Posted 31 August 2003 by taly01

I have been making PC game mods for Nth Africa desert and the figures i settled on for the 47/32 and 75/18 efetto pronto was 69 and 90mm respectively (against vertical plate). This was from guess-timating the performance from similar vintage weapons recorded performance.

The HEAT would have had consistent penetration over all ranges as it burns through the armour, but given the lower velocity required for effective HEAT rounds penetration effect they would be harder to hit a target with especially at >500m. Also poor streamlining of WW2 HEAT rounds.

The 47mm HEAT would only burn a hole through the size of your little finger! So it would need to penetrate near something explosive or crew area to knock out a tank.

I have read accounts that the WW2 German 75mm HEAT (450m/s) had a good effect but was less accurate than the conventional AP (790m/s). Also, accounts say that the early Bazooka ~50mm was not a very effective weapon (that's why Germans made their "bazooka" 88mm). So the 47/32 would be even worse.
------------------
Posted 31 August 2003 by Attilio

The hollow charge for the German 7,5 cm L /24 achieved penetrations of Gr 38 H1/A 70 mm
Gr 38H1/B 75 mm
Gr 38 H1/C 100 mm

I think that 90 for 75/18 is unlikely

In March 1942, in the Saunnu (Cyrenaica) area, the 12th Autoraggruppamento (the Italian "experimental" unit in North Africa) put the EP rounds for the WWI vintage 75/27 field gun and 100/17 howitzer to the test. Two 75mm and two 100mm EP rounds were shot at a captured Crusader MkVI tank at a distance of 550 yards. The 75mm rounds easily smashed and penetrated the side and frontal armor plates, with plate shrivelling (presumably due to the "boiling jet" effect). The 100mm rounds disintegrated the frontal armor and popped the turret out of the tank.

The overall effect of the rounds was described as being decidedly superior to that of the regular AP shots for those calibers. Considering the obsolescence of the 75/27 and the 100/17 guns, it was a remarkable upgrade. Such EP rounds should be quite effective even against Grants and Shermans. Of course, there were too few EP rounds available.

Best regards

Attilio
 
Top