To celebrate Ruger day this year, 10/22/25, I ordered some parts for my 10/22 rifle, and Mark II and 22/45 pistols. I already bought a pair of TANDEMKROSS Plus 1 Magazine Bumpers for the Mark II mags, which have since been discontinued. And I had more than enough TANDEMKROSS Green Springs, 2 3-packs. So I removed the magazine block retaining plungers from all 4 mags, chucked them in a cordless drill and spun them in 220 grit sandpaper to polish them up. One from a Mark II mag is a much different shape (pic 1). I also sanded the molding flash off the top, front, and back of all 4 mag followers and cleaned them off.
I think that was the mag that the bottom of the tube was squeezed in on, and I forced a very large screwdriver into it to spread it out farther. That was probably the one with a much shorter spring in it (pic 2). The Green Springs are longer than the longest of the 4 springs. One of the Mark II base pads was solid black like the ones for the 22/45, and the other one had a silver color piece stuck on, and looks kind of like a hollow rivet on the inside. The logo is upside down compared to the one molded in on the black mag (pic 3).
I replaced the Mark II base pads with the TANDEMKROSS Plus 1 Magazine Bumpers (pic 4). There were 3 different mag follower buttons on these, one was grooved and 2 others were the same size but smooth, and one was smooth but smaller than the other 3 (pic 5). I replaced all 4 with Volquartsen Magazine Follower Buttons I already had. I was working on a Gadsden Flag TekMat (pic 6) to keep everything clean, and make the parts easy to see.
https://tandemkross.com/green-springs-magazine-springs-for-ruger-mark-series-3-pack/ https://volquartsen.com/products/1236-magazine-follower-button-for-ruger-pistols