Old Mags from the 60s

[alkyal]

Have looked @ many OLD vintage mags from the 60s. They all seem to have some sort of additional rectangular addition on the rear of the main body. Cant tell if they were made that way or that was an addition put onto an existing mag. What was inside that area of the mag and what was its purpose?

[Spud Miller]

 On the old Harmon & Collins and Schiefer mags, that big area on the side houses the coil. The coil wire comes out of it and plugs right on to the top of the mag.

 Spud

[alkyal]

So those Mags, unlike an older Vertex didnt have the coil inside the main body. The old AA/GD- The NITRO GASSER that I worked on in my much YOUNGER days had a Schiefer mag and Clutch in it during its life thru the late 60s. Thanks for the info.