I'm starting a new post to go along with Evildoctor235's earlier post to maybe help a few others, and maybe see what else we can discover.
He had some early .22 magazines that wouldn't go all the way into his gun. (See his post about that.)
He was kind enough to send me one to check out. His thoughts were possible counterfeit, or maybe a prototype magazine. He studied Chad's book that has a picture of several Std Auto & MK magazines.
The mags in questions were of the early Std & MKI type,, that hold 9 rounds, and have an unmarked silver plated base. They looked "normal" in general,, but why they wouldn't fit was a puzzle.
So when he sent me one of the mags in question, I took it & studied it. I then took out my earliest Red Eagle, (serial under 3000) and the mag in question, went right in & fit fine. I took out a 5 digit Red Eagle, and the mag did the same thing to me as it had been doing for him. Stopping about 1/4" or so from fully inserting.
That made things get interesting.
I started CLOSELY (under magnification) my (2) Red Eagle mags, as well as the one he sent me. I put a piece of tape on his mag to make sure I didn't mix it up with mine. I used my calipers to measure as many things as I could think of. I disassembled all 3 mags & made measurements. Only a slight difference in the followers was found.
I also tried to swap my (2) Red Eagle mags around. They both fit fine in my 5 digit,, but only one fit in my low 4 digit. It did the exact same thing as the one he sent me did. Stopping before seating.
And under my close examination, I noticed the follower button on both my mags kinda "canted" outward at the top edge,, while the one he sent sat flat. The only semi-obvious difference.
Back to the books.
I studied Chad's book a bit more,, reading about the early Red Eagles & some of the internal changes made during the very early production. (Pages 24-26 in Chad's book on Ruger Semi-auto's.) While the book doesn't address the issue directly,, there is info on some of the mechanical changes to the bolt, & firing pin etc that got me to studying things closer.
Next,,, I took the grips off both my Red Eagles,, and tried to see if I could discover any differences. Nothing I could fine with a light & my eyes.
I went back & disassembled & swapped followers & mag bodies etc around, and at one point, I got another hang-up, but then it went away.
Conclusion?
I think that during the very early years,, as Bill was developing the Std Auto, he had to "tweak" the gun to get the reliability necessary. And quite possibly, the very early frames or some other internal spot got a slight modification, that allowed the mags to work as they should. It just hasn't been closely noted. (Well, at least as far as I can uncover.)
Earlier guns, shipped & all, didn't get the internal tweaking that is obviously minor. And since it's LONG AGO knowledge that has passed with those that were there,, we may never know exactly. But the very early magazines, combined with the slight difference inside the frame can cause the early magazines to not fit in later guns.
And since most folks who have the very early Red Eagles don't shoot them much,, OR,, do not have different magazines, nobody discussed this before.
Anybody have any other thoughts, similar issues, or ANYTHING else to add?