Unusual Mark On Cartridge Counter

[cirelaw]

I wondered is the mag started out as a Swiss and added a Powell device?

[Ron Wood]

Originally Posted by cirelaw

I wondered is the mag started out as a Swiss and added a Powell device?

It is possible, but in addition to the slot and indicator you have to modify the follower and the spine of the magazine at the top. It is difficult to do it right and most attempts so far have not been done well.