I ran across a bucket of fired .308s with some metal links at a garage sale one day. The guy gave them to me so I went home and started to cull through them when I ran across several on these cartridges that I have never seen before.

NOTE: The original pics were 1MB each so I resized them down to 30-40K.

The first pic is a comparison between the unknown{left} and a .308 Winchester{right}.

Pic1

Next is a comparison between headstamps.

Pic2

Next is a cutaway of the unknown case - I used a dremel to slice it in half.

Pic3

Last is a pic of the inside cartridge.

Pic4

The headstamp reads: RG 83

Dimensions:
Length: 2.007
Caliber: .355 - .360
Diameter @ Rim: .471
Diameter @ Shoulder: .457
Diameter @ Neck: .394

Inside Cartridge Rim Diameter: .344
Inside Cartridge Case Diameter: .293

These measurements are approxiamte because this is a fired case and has some slight dents and dings.

The fullsize pics can be seen at:
Case01
Case02
Case03
Case04
Case05
Case06
Case07
Case08

Thanks,
Brandon

What you have seems to be the 9mm SMAW spotter; basically, a self-loading gun firing this ammo was attached to a shoulder-fired anti-tank weapon. On sighting a target within range, the 9mm was fired until the target-marking bullets flashed to register a hit, whereupon the main weapon was fired.

It was an amazingly complex cartridge. Somewhere in my disorganised filing system I have the full details, but from memory it used a high-low pressure system with a .22 (Hornet?) cartridge acting as the high-pressure element, inserted in a 7.62x51 case necked out to 9mm. That's why the base of the case looks so odd.

In this pic of spotting rounds from the photo gallery on my website, the 9mm SMAW is the sixth round from the left: http://www.quarry.nildram.co.uk/Spotter.jpg

Tony Williams: Military gun and ammunition website and Discussion forum

As fate would have it , I have a photocopy of some information on the 9mm SMAW / LAW 80 . I picked up an example of the spotter tracer at the weekend , previously owned by a Gurkha regiment , but we wont go into details on that here ....

If you want I can scan it and send it , contact me through the pm system . Its only two pages and has a great description and diagram .

Definitely the 9mm SMAW. Loaded round featured a blunt, round nose projectile with red laquer on the tip. Headstamp is Radway Green, the primary British arsenal.