Chris I like it!
If I'd realized the issue with the assembly ( note carefully artful skirting of names!) when I was assembling the model I likely would have
chosen a solution such as you two came up with or my original thought of 'building in' a bearing such as I have on some of my other models:
bearing ball groove
Corresponding gear with bearing groove
I wouldn't have used a internal gear as part of the 'bearing sandwich' for the M3 but just another plate with a groove. The photos I've inserted links for were for the turret drive of my 1/10 King Tiger to illustrate the idea.
Since I had the upper hull already built and painted I opted not to disassemble it and make new holes required to mount a lower support. In other words
I didn't want to scratch the paint! However I believe your solution is the better way to go if one is at an earlier stage of construction.
John I've used those servo delay gadgets, in fact I have some. When I made the video I used another receiver and radio with just the basic functionality to test; not the radio I'm actually using for the model. With that proper radio I'm planning to use a pot to control the 75mm and for that channel's output I can define the rate to be a different curve to prevent the jerkiness seen in the video. I thought the same as you probably were: the movement is not heavy gun-like and far too jerky to purpose. "In production" it shouldn't be that way...
Wonderful to see and hear of other ways to do things, I learn something new every day!
Jerry
] is the ideal solution. But that would have needed to be part of the original design. I don’t imagine it could be retro-fitted without major work, which would certainly scratch the paint