I picked up two all steel blued Colt 30 round magazines. They are the full continuous curve type. A 1.90 OAL M200 blank is too long, but an early 1.70 OAL XM195 grenade cartridge or the 1.70 OAL MARS cartridge should fit fine. All I have to test is a M200 blank.
I have seen a photo of a 601 with a full curve magazine and several rifle grenades setting on the same table. Hardly proof. But at least shows them together.
Is it possible the magazine was used to test the MARS round in a full sized M4 carbine for performance before the shortened receiver and mags were made?
The follower is too heavy to be aluminum and is probably pot metal, the body and floorplate are also steel.
So what do the great minds here think? 30 round early XM195 grenade cartridge magazine,  MARS cartridge testing magazine, or something altogether different?



left, early 1.70 OAL XM195 grenade cartridge.... right, M200 blank


full curve on left..      standard 30 mag on right

Thats what it looks like! its way shorter than a standard blank cartdridge.

Well I know just what you have and its not good news.

Those are mags for the Japanese MGC replica M16A1. They fire short cap blanks. See the links below...

http://www.mp40modelguns.com/mgc_m16a1.htm

http://www.mg-props.co.uk/m16a1mgc.htm

http://www.mg-props.co.uk/m16mgc.htmhttp://www.mg-props.co.uk/m16mgc.htm

http://www.mg-props.co.uk/images/mg/mgcm16e.jpghttp://www.mg-props.co.uk/images/mg/mgcm16e.jpg


Sorry its not good news, but thats what they are.

Thank you very much carbinekid.
That solves that mystery in a hurry!
No great loss, now that I know what they're for I can unload them and move on.

That looks right, but I'm surprised they have Colt baseplates.

That's what they'll be saying 10-20-30 years from now when they find one of our clones.

The Japanese replica guns often had very accurate markings. I believe colt did raise a dispute at some point and I've seen some that had the markings milled off.

Although it wouldn't be hard to swap out the floor plates.

I think it is interesting that they copied an early fully curved Colt 30.....