APDS 17 Pounder

[Spaceinvader]

Projectile suitable for use with two different case sizes. The original 17 Pr and the later 77mm (which was actually, like the 17Pr, a 76.2mm calibre. It used the 3inch 20cwt sized cartridge case).

I have seen this as well however this older thread on the 17pdr APDS rounds user TimG mentions the shorter 77mm case formed from the 3" 20cwt cases was not suitable for use with the Canadian designed projectiles. I suppose it would depend on when that decision was made to not use the 77mm cases (before or after production of the projectiles) but seems strange they would continue to mark projectiles with that distinction.

Show your 17 PR Rounds

The drawings, if drawn correctly, just about explains it all. The Canadian APDS was screwed and glued to the case and M8’s was probably punched stabbed as well. Examination of M8’s projectile reveals there are radial weakening slots machined around the base (from the drawing it would appear...

www.bocn.co.uk

 

[Spaceinvader]

This photo is from the same thread I posted above and was originally posted by user AE501 (I highly recommend reading the thread as he posted far more information), showing the Canadian design of APDS projectile fitted OVER the case mouth and also mentions the use of adhesive to secure the projectile to the case. This is the only cartridge that I can think of that uses a design like this, I have also never seen one of the special "coned" cases for these in a collection. Ive just been using a regular 17pdr case to display mine.

Also attached are 2 photos of I believe DJ's fantastic cutaway cartridge.

Show your 17 PR Rounds

There is no mention of an APDS shot in Bonnex's document which is dated 1945. What does that mean? My APDS is dated 1943. They should be in this manual.

www.bocn.co.uk

 

[Gspragge]

The Canadian 17pr shot is quite different from my British example, it wouldn't fit like this one at all.
Though with the casing ending just under the rotating band it could well be coned in at that point
which is not nearly as extreme as the Canadian example, more like an exadurated 18pr squeeze.
Just add some goo to seal it perhaps rather than actually glue it (unless there were issues of it loosening if it wasn't coned at all ?) .
Maybe the glue issue was really a sealant issue that held to well ? Like the good old Pettmans cement
that was used liberally in the past.
Now I'm a little unclear on this, does the casing end with the threaded screw in area or does it go up further coning inwards.
At any rate it's a different attachment from the British example. I must ask though do any of the Canadian projectile examples
have the internal threading to screw onto the casing ? Having never seen one I have to ask.

 

[RichardB]

in the clip, it shows a very similar projectile, and which would seem to corroborate the notes on your drawing about the projectile being M331, using the normal Walker Bulldog case. (with possibly different crimping)

So the question now is, were these projectiles ever fitted to a 17pr case, Or did the designers borrow experimental 17pr projectiles during the design process for APDS with the Walker Bulldog. I guess I’m a little hung up that these projectile don’t fit in the 17pr case, but could be wrong.

Rich

 

[Spaceinvader]

The M331 was never fitted to a 17pdr case as far as I’ve ever seen, if that’s what you mean? The M331 projectile also lacks the extended skirt that the Canadian 17pdr projectile has to attach it to the casing. I have both projectiles in my collection so I will try and upload some examples soon.

As for the Canadian 17pdr APDS design the inside of the projectile skirt is indeed very finely threaded to help attach it to the coned cartridge case.