You can also DIY hi-caps from Uzi mags - the internals slip right into the MP40 mags.
Bone question ... the internals from any Uzi mag or is a particular brand recommended?
Cheers
Marui Uzi hi-caps!
check this thread for a pictorial how-to: 
viewtopic.php?f=13&t=2104
“I wanted to come to the Volga at a specific location at a specific city. By chance it carries the name of Stalin himself. So don’t think I marched there for this reason – it could carry another name – but because there is a very important goal... this goal I wanted to take – and you know – we are very modest, we have it already."
Adolf Hitler, November 1942
"Comrades, Red Army men, commanders and political workers, men and women guerrillas! It is on your perseverance, staunchness, fighting skill and readiness to discharge your duty to the country that the defeat of the German-fascist army and the liberation of the Soviet land from the Hitlerite invaders depend! We can and must clear the Soviet land of Hitlerite vermin."
Joseph Stalin, November 1942
Available from eHobbyAsia for $26. Cheaper than the locals even when express shipping is included.
Cheers guys
