I got an MGC68 magazine; same external dimensions as the magazine above, but was used to hold the PFC cartridges shown in oic above...MGC
[Model Gun Corp/Japan] also made a steel MP40 replica...
Here's a comparison of the 'real' mag with the MGC68 mag...
They would be easy to pass off as original at a gunshow unless you knew what to look for
(of course, the stamped 'MGC68' is an easy tip-off)...
The MGC69 mag is about 1/8" shorter that the 'real' one, and the 32 rd indicator holes are located differently...(The MGC68 PFC cartridges were oversize so as not to feed in a real MP40 and vice versa)...The backstrap is also a separate piece of steel sheet spot-welded on...And the 'real' MP40 mag has the back of the feed lips butt welded (the MGC68 is not)...
The spring is shorter but interestingly is the same wire diameter.