Cart 40mm HE-T and the various ages of components

[pedro]

Back in 1982 I was able to breakdown and recover a box of Naval 40mm HE-T. I still have the inert parts and it's and interesting exercise in the way Defence re-uses and re-manufactures EO rather than just destroying it.

The Projectile is marked as 40mm MO MK4T Lot 257 3/54 BS It is fitted (or was) with a tracer igniter and a FZ 306.

The Fuze is marked FZ 306 M121 173 80 01

The projectile would originally have had a 243/247 type fuze and probably had more than one.

The Cartridge case is a complete replacement for the original. It is marked 40mm Mk4 Lot 104 MF 1971 A^N and this was filled with Prop NQ (as I recall) in slotted tubular form.

The primer is Perc No12 MkN4 Lot 15 5/71 Me and filled MY 2/72

So the projectile was 28 years old, the case propellant and primer 11 years old and the fuze mere 2 years.. Refusing was done to a. upgrade to the Fz306 mainly as the older 243/247 sereis suffered from copper azide contamination and was withdrawn from use and no longer manufactured.

The drill round is a gratuitous pic.

 

[Darkman]

Hi Pedro,

Thanks for showing. Very interesting.

I love how the components have been updated and re-used, but I was wondering why the projectile was chrome plated? Also wouldn't the original fuze have been a 255 or 259? The projectile is crimped into the case 1940s-60s style (continuous) not the 1970s-90s segmented method. I have seen rounds done this way in later years for training purposes using the original factory crimp machinery.

It appears Australia must have developed the 306 fuze sometime in the late 1970s because as far as I am aware no other country used them. The 306 fuzes I have seen (1980s dates) are marked "AN306".

Cheers, Graeme

 

[raymeketa]

Could it be a dingbat?? That is, put together from various bits and pieces to represent a real cartridge. Not necessarily intended to deceive but simply to have one for display. Many artillery cartridges are like that.

Just sayin'

Ray

 

[HAZORD]

Actually, with the chrome projectile and the aggressive crimp, it looks like a drill round.

 

[weberoed]

Though not really; related to the content of this thread, when I was in Viet Nam, the 40mm Duster was a real life saver one night. I was attached to an armor BN scout platoon and we had met up with two Dusters that we were to escort to a Fire Support Base the next day. That night we set up our night defensive positions, the plt sgt said put the Dusters in the mix, but after dark for one of them to move to a slightly higher position inside out perimeter, and for the other one to move to a different position. Around 3 in the morning a NVA/VC unit hit us really hard. I was behind a .50 cal on a M 113 APC. I had already gone through 100 rds when all of a sudden these big ass green tracers started flying over my head and then multiple and I mean multiple explosions in front of my position. We lost 2 APCs and a Sheridan, 2 KIA and 11 WIA that night, but it was the Dusters and their 40mm that saved us. Great system wish they hadn't gotten rid of it.

 

[HAZORD]

They have a Duster as an intersection ornament on the National Guard base in Boise. They used to fire them out on the Guard range among the Shermans, M60's and everything else over the years.

 

[pedro]

All, My 40mm HE were real, not dingbats. Can't explain the inerting details here. The Projectiles were chrome-plated after inerting, (along with a few excess 36M) as this was the fashion at the time for presentation items (gold watch equivalents). Of note, at the time I had no way to professionally re-crimp the projo to the case.. but, on the following posting I moved to a Proof and Experimental range, where we had all the toys to build up cartridges from the base components; as base as making up 105mm M1 charge bags from bulk propellant, charge bags, set of scales and a sewing machine. In this location there was a roll-crimper with the relevant die for the bofors... made a professional job easy. We also had working Bofors (land AA version) still in use for Proof. For Graeme, yes 250/251/255/259 would be more correct. I plucked two fz numbers from memory (travelling with no reference material) mixing up 2pr and 40mm. P