[R-390] Differences in Slug Carriers

[JamesMiller]

On the metal carriers that hold the coil slugs, in some radios you see a rod
running from front to back.  At each end of the rod ar small cylindrical
bearings that ride on the cams.  In the S&W radio I have, the slug carriers
have this rod in them front to back.  In my Collins 390a, there is no rod.
Only a metal tab at each end that holds the cylindrical bearings.   Did
Collins never use slug carriers with this rod?  The rod seems to offer more
mechanical rigidity or stability than the "tab" type.  I would have thought
Collins would go for the more substantial design.