20mm T3

[bacarnal]

While going through my junk storage, I mean my workshop, I was shifting boxes around and discovered this. I don't have much to go by on it and being lazy, haven't done a search here yet, but thought I'd post it anyway. Length of case is 9.25" (23.5cm) and the base is at 1.965" (5.0cm). Found it in a pond along with some .60 cal casings (elec and percussion) and some other oddities about six years ago. Cheers, Bruce

Okay, THAT didn't take long. The search provided OODLES of 20mm, but no T3. That would beg the question then of what the heck do I have? Base reads "20MM T3, LOT 22065-1 (small ord wheel) FA 1942". Primer reads "LS-6-285 45, M38B2". The primer on the only other case I have that is neck less has a greenish phenolic substance around the center which makes me think of electric primed, but I could be wrong. Ideas? Comments? Cheers again, Bruce.

 

[SG500]

Hi NICE case thanks for showing it.
The only information I have is in the book "Von Flanschengeschossen und Wolframkernen by Manfred Stegmuller" I attach the page. Perhaps one of our German friends could help translate?
Dave.

 

[kahu1]

Looks like a USN 1.1" case necked down to 20mm , possibly a development/proofing round?

Bob

 

[bacarnal]

Dave, Thanks for that picture.
Bob, That's what I thought, but when I got a 1.1 beside it, it was obvious that wasn't the case. When I measured the base of the 1.1" it came to 1.715" (4.356cm). Well, another mystery. Cheers, Bruce.

 

[HAZORD]

@SG500,

Dave, the previous page (214) mentions U.S. developments. The English translation is on page 217.

I'm wondering if EODGuy has about 3 of these cases. Bob, are you out there?

 

[kahu1]

Dave, Thanks for that picture.
Bob, That's what I thought, but when I got a 1.1 beside it, it was obvious that wasn't the case. When I measured the base of the 1.1" it came to 1.715" (4.356cm). Well, another mystery. Cheers, Bruce.
View attachment 76348

Yeah, checked the size of 1.1" case.Was going on visual rather than dimensions!. Now looks more like (?) a necked down 37mm M17 case,pressure testing?....someone will have the exact answer!

 

[pysall]

Following SG500's request.....

"After the capture of a 28/20 s.Pz.B 41 in North Africa, several experiments were carried out in this caliber. Apparently they wanted to check/compare the performance of the taper-bore weapons against cylindrical bores with the same end-calibre and powder charge. For this purpose appropriate cartridge cases were produced"

Picture 231. "American cases 28 mm x 188 (28/20) - US designation 20mm T2 (above) and 20mm T3 (below - further development of the T2 for taper-bore) both manufactured by Frankford Arsenal (FA) in 1942".

Hope this helps,
pysall

 

[EOD]

It also says that the 20mm was not for conical bores.

The 20mm case has no relation to the 1.1 inch as it uses the 28mm as a basis which is of German design.