Centurion 20 pounder Ammo

[mick whittingham]

Hi all,

I have it in my head to make a number of different 20 pounder rounds for my Cent and I'm finding it hard to come up with any dimensions that might assist other than bore of the actual barrel.

I have sourced a number of photo's from the web which show APDS and standard rounds so fashioning the shape of the round and shell case should be easy lathe work.

I just want to make them as near as possible to the right scale size. So does anyone have any dimensions or drawings for the ordnance or photos which will assist in detailing.

I bought the brass thick walled tubing to make the shell cases from but don't want to start until I am sure of the sizes as it costs £2.00 per inch!

Best wishes to all

Mick

[Stephen White]

Good call Mick. I'll see what I have. Firstly, AFV Club, who make the 1/35th Cent kits, now do an add on package of 20 pdr rounds. Might be useful to scale up:

http://www.armorama.com/modules.php?op= ... nt&id=3757

There were six types of rounds, from the left on this photo:

Shell Smoke
Shell Cannister, anti-personnel
Shell HE-T (high explosive - tracer)
Shot APCBC (armour piercing capped ballistic cap)
Shot APDS Mks 1 & 3 (armour piercing discarding sabot - an improvement on APCBC)
Shot DS Prac (discarding sabot practice (soft steel core)



Some more photos:









I've nothing on dimensions to hand but there are cutaway diagrammes which you could scale in the 20 pdr handbook at the Tank Museum. I've haven't got a copy but I'll look for something online.

All for now.

Stephen

[Stephen White]

Mick - bingo, from The Serious Modeller's Guide to Centurion Gun Tanks Vol 1 (for research purposes only):



Regards

Stephen

[mick whittingham]

Hi Stephen,

many thanks for the wealth of information. I can make an educated guess on the diameter of the shell casing and come up with something that looks right.

I think I will make a standard HE version and an APDS shell just to see how they look.

I have been working in the shop today on finishing my sheet metal brake and in completing the fabrication work on the foul weather hood storage bin. Some filling and sanding and all will be revealed.

Thanks again for the super information and I hope your build is progressing as well as usual. The gear casings are truly beautiful.

Best regards, Mick

[Stephen White]

Mick - the most amazing service from Creative Models - I ordered on Christmas Eve and the package arrived today:



Regards

Stephen

[mick whittingham]

Hi Stephen,

many thanks for the photo of the brass ammo you have acquired. A very impressive response as you said.

Would it be possible for you to measure the shell casing major diameter for me so that I can scale up from 1/35th to 1/6th to give me an idea.

The differing type of projectiles are interesting and look to be covered in your earlier posts so I will have a stab at one or two types.

Many thanks for your assistance so far,

Mick

[Stephen White]

Hi Mick

Measurements as follows (first figure the 1/35th and second the 1/6th):

Max diameter at base of case: 3.67/21.4mm
Diameter at neck of case: 2.37/13.8mm

Best regards

Stephen

[mick whittingham]

Hi Stephen,

that's fantastic, many thanks for taking the time to measure the casings for me.

I am shifting the shop round a little to make way for a tapping machine and so have not had time to work on the shells yet, I have the blanks ready to machine and will make a start soon.

Model engineers club tomorrow so I will be laying a little bit of railway track bed for them as this is the best time of year to do ground works apparently.

Chat soon and again many thanks,

Mick

[mick whittingham]

Hi all,

I have had a go at the ammunition for the 20 pounder gun and I am fairly happy with the results. I think the casing is about 10mm too short but the next version will rectify that. I have left the shells plain steel for now but will paint them ass appropriate prior to mounting them for display with the Cent.

The do look good on the mantelpiece though it has to be said, and more folk at work have asked for them as curiosities.

Just rescued a very ill little dog and so model making is curtailed while we nurse her back to strength. But normal service will be resumed as soon as she is fit to come into the workshop.

Regards, Mick

[Stephen White]

Mick

Congratulations - they look magnificent, well worth the effort, some class machining.

You rarely saw live rounds on operations - they were either in their safety packaging or stowed within the tank. We were taught that they should never be left outside the tank longer than necessary to load them, partly because of the risk of damage, partly because there was thought to be a (very small) risk from radiated energy from radio antennae.

But in Vietnam, I've seen a number of photos of both live rounds and empty cases on the back decks of tanks. The empty cases are easy to understand - if they were discarded, they could provide a very useful means for the Viet Cong/NVA to create booby traps and IEDs. So after firing, they were often stowed externally on the back decks until they could be disposed of safely. Here are some examples (the second photo is obviously bombing up):







For my Aussie Cent, I certainly think it would be good to make some empty cases.

Thanks for posting. Enjoying all your photos.

All the best

Stephen

[mick whittingham]

Hi Stephen,

thank you for the words of praise, they mean a lot to me when coming from such a committed and skilled modeller as you. And who has actual experience of the forces and practices relating to armoured warfare. Your advice on not leaving live rounds laying around sounds like common sense but I was planning on using my examples in just that way! I think I will stick to spent cases and keep the live rounds for a display stand.

I think that your Aussie Cent will benefit greatly from some spent cases to further enhance the illusion of perfect miniaturisation that you have embarked upon with this build. I will turn a new case with the longer specification and post a comparison image for you to see. Turning it from hollow tube created the problem of an open base which I had to correct by making a thick sheet brass insert and silver soldering it in place. I then used a tool post mounted centre punch to mark the firing details on the base and I will possible pre-stamp the brass disc with suitable characters before soldering it in place and cleaning the brass up.

Working tomorrow so Sunday will be my next workshop day, the new dog is doing fine by the way and will be covered in metal swarf before you know it.

Best regards as ever, mick

[mick whittingham]

Hi all,

After sorting the dimensions and a scheme of working to produce the shell casings in the most efficient way I have moved forward a good bit.

From wooden prototype to finished article

I now have three shells in their various stages of production from lathe through to silver soldering the base cap in place prior to finish machining.

Not altogether sure of the base markings but as the items won't be subject to close scrutiny I might just skip that step.

The actual projectiles all appear painted and I wondered if they were actually painted for recognition sake or are just painted now for display in museums.

All I have to do now is get rid of half a pound of brass turnings from the lathe bed.

Ciao for now, off to plan my next small steps.

Regards, mick

[mick whittingham]

Just another couple of views of the Ammo

[Robert E Morey]

Mick,
Those shells look fantastic. Lovely bit of lathe work. I like you hollow design with end cap. Are you going to cast them in resin or machine the remainder for what you need?

Mick can you recycle your chips? Here in the US a few pounds of brass or copper is worth a few bucks. Usually enough to buy more material with.

Steven - great historical photos and research as usual.

I enjoyed this post, best regards,
Bob

[mick whittingham]

Hi all,

I have completed three rounds of ammunition for display and have been pestered to make ornamental shells for friends at work but I may just field that one into the long grass so that there are not future reports of live rounds floating round the county lol.

Shorter round for comparison

shows base cap detail

I can now clean all the brass turnings up and get back to something more meaningful, I am going to make a start on the modifications to the mudguards and have completed another machine tool to assist with the bending and forming, a small press brake tool.

I will keep the group updated on my build thread.

Best regards the everyone.

Mick