Iceni

The GR300S is Magnesium as well.

Very light, Very Strong. It'll fizz if you pop a drop of vinegar on some bare metal.

Ahhhh I always did wonder about it.  I remember thinking back in 2004 when I got it they've sent me a plastic version haha.  So light

Those bodies are by far the best M4 bodies ever produced.

They don't have any of the issues of later production, and I've never heard of one cracking.

The only issue is the bolt release scratching the body.

You should get yours rebuilt. Drop one of those E&C boxes into it with a basic fet and use it to confuse and upset M4 experts who will tell you off for the stock

The only thing you can do with magnesium if you want to spruce it up is paint it. I have no idea what they use the blacken it, but I would avoid the ALU black as it may eat into the metal.