US Experimental cases

Today I acquired a ziploc bag of cases labeled simply “US XPTL CASES”. here is a photo of what it contained: Please could I have more info on them. All are brass, all are rimless except no. 6.

Descriptions: (From left to right:)

  1. NUPE, OAL 63.3mm, Appears to be .30-06 necked down to 7mm, headstamp “W C C 6 3”. Definite step in shoulder from necking down.

  2. NPE, OAL 56mm, internal neck diameter approx 6.5mm. headstamp “F A 30” . Case taper has a definite point where angle incresed around halfway up case.

  3. NUPE, OAL approx 52mm, inside neck diameter approx 5.5mm. Headstamp “F A 7 1”. “SAW” written on case. Is this a 6mm SAW?

  4. NUPE, 48.3mm OAL, inside neck diameter approx 5.5mm. Extremely thick rim (2mm). No headstamp.

  5. NPE, OAL 44.6mm, inside neck diameter approx 5.5mm, no headstamp.

  6. NPE, OAL 44.6mm, inside neck diameter approx 5.5mm, no headstamp, rebated rim

  7. NUPE, OAL 43.6mm, inside neck diameter approx 6mm, headstamp “F A 7 1”. appears to br 5.56 NATO necked out to 6mm with slightly shorter shoulder.

Any info that helps identify these would be welcome.

Falcon, well done! Some wonderful cases here.

  1. Not sure. Sniping round I think.

  2. .256 Double taper. Also known with a FA 28 headstamp. Experiments related to the necking down of the the (experimental) .276 Pedersen. A wonderful case.

  3. 5.56 x 52 SAW prototype case. Only known as NUPE.

  4. I think this is actually a Swiss 5.56mm Eiger case.

  5. don’t know.

  6. .224 E5 case. Rare.

  7. 6 x 44 Pre-SAW (Squad Automatic Weapon)

If #6 is the .224E5 Winchester, then #5 is probably the .224E4 Winchester.

Thanks for your help. Can someone post a photo of the .224 E4 round? When would be the approx. date of manufacture for the .224 E4 and E5 and where were they made, as they have no headstamps.

There is a photo of a 5.6mm Swiss Eiger round on Tony Williams’ website, I think it is safe to say that is what No. 4 is looking at the photo. Can anyone post any more info about this round?

Anyone have any ideas on the .30-06/7mm?

I compared #1 side by side with a commercial .25-06 round and they were identical. I think someone put some .30-06 Brass through .25-06 dies to load .25-06 ammunition for shooting and one found its way into the hands of someone who thought it was a US experimental because of the US Military headstamp. The inside neck dia. is closed to 6.5mm than 7mm. Thes step in the neck that looks to have been made by a resizing die also backs up this theory.

@Paul: Can you give any more information on your “sniping round” suggestion?


Here’s a photo of an E5. I stole this image off the Forum. I can’t remember who posted it. Paul?

The E4 is the same but with a standard rim. Both are basically the 25 Remington case necked to .224, shortened, and with a 23 degree shoulder. In fact, there is an old wildcat from the 1930s and 40s, made from 25 Rem brass, that is nearly identical to the E4. So nothing is really new.

All of these cartridges are from the 1950s and 1960s. I beleive the Woodin Lab has several with various headstamps.


Cheers Ray, that is definitely what I have. Neither of my E4 and E5 have headstamps.