What is this magazine?

[DB2]

I am still trying to figure out some mags. This worked very well on the rifle mags. So I figured I'd try with the handguns.

What is this for? It has a different base than the Lugers did.

[Rone']

I think it is a Jap Nambu mag. Ron

[Demophilus]

Might be a Nambu.

[sorensen440]

looks like a nambu

[pottymouth310]

it's a Nambu