#1

The 40mm with the black plastic proj is for blank firing. It is filled with sand, and breaks up on leaving the barrel. I’m not sure if any countries other than the UK used these.


#2

falcon,

The black bakelite 40mm round is more properly described as “Break-up” because a lot of broken bakelite, small lead shot (NOT SAND) and felt wads were fired at high velocity, hardly a “blank”. They killed seagulls at about 50 yards range if you aimed right.

The lead shot brought the weight of the projectile up to about 2 pounds to ensure sufficient recoil to function the gun. Wherever possible, old worn barrels were used for firing break up to save your good ones.

There was also a 20x110RBmm Oerlikon break up round in UK service.

gravelbelly


#3

I have one of these break up rounds which is filled with fine lead shot and a wadding plug.

Just weighed it and gravelbelly is spot on,it weighs exactly 2 lbs!

I also have a Bofors case with stencils on which I presume was for the break up round,the stencils are, B.U. Mk N6.

Regards,
Andy


#4

[quote=“AndyD”]I have one of these break up rounds which is filled with fine lead shot and a wadding plug.

Just weighed it and gravelbelly is spot on,it weighs exactly 2 lbs!

I also have a Bofors case with stencils on which I presume was for the break up round,the stencils are, B.U. Mk N6.

Regards,
Andy[/quote]

That is the one. The base of the projectile was open to allow the gas pressure in and help to burst the bakelite. The beach in front of the Naval Gunnery Training establishment, Fraser Battery, Eastney, Portsmouth, Hampshire used to be littered with shards of black bakelite. Sometimes pieces as big as 25% of the original projectile would survive. Occasionally a complete bakelite casing, empty, broken through the crimp groove would be found. These were the result of a fumbled load which broke the plastic, dumping the lead shot into the auto-loader. The crew usually tossed the bakelite over the fence onto the beach. Both case and projectile were stencilled, black on the brass, yellow on the projectile.

gravelbelly


#5

Dutch break-up Ammunition made by NWM de Kruithoorn
different calibers 20mm, 25mm, 35mm,40mm

NWM Break-up ammunition can be used in guns with calibers ranging from 20mm to 40mm.
The handling,feeding and firing of break-up rounds is idetical with a target practice round.
The core of the projectile contains specially treated metallic powder.
In the top of the projectile a faom polysterence cone is located.

NWM offers a wide range of break-up projectiles
-40mm MN19 for Bofors 40mm L70 guns
-40mm DM18A1 for Bofors 40mm L60 guns
-35mm MN16 for Oerlikon guns
-30mm Mn15 for Hispano Suiza HS831 and Rarden guns
-25mm MN14 for Oerlikon gguns
-20mm DM78A1 for Hispano Suiza HS820 and Rheinmetall MK20 RH202 guns
-20mm MN13 for Oerlikon 5TG and 204 GK guns
-20mm MU10 for Vulcan Air Defense System


#6

Gravelbelly, mine has a closed plastic base stamped “SX15SA” and not an open wadding base. It can be seen through the primer hole if you shine a torch into the case.


#7

Mine has the same screw in base with the same number moulded into it.

Was this base supposed to be left on during firing?
My proj is stencilled in white,not yellow.

Regards,
Andy