This is simply a bolt racker for the Ruger MKII pistol. These are similar to manufactured aluminum versions you can find online at various websites.
But why buy one when you can print one.
I've printed the single tab version. My prototype fit and worked, but it felt a little flimsy. The prototype only had the stop (the little bump on top of the handle by the hole) on one side. I'm hoping that having the stop on both sides of the handle will add some rigidity and prevent any give or flexibility.
These aren't meant to stay mounted on your bolt. Cycle the bolt, then put the charging handle to the side. The reason for the hole in the handle is so you could tie it to your wrist if you wanted.
The RING version of this has a 1.75" (44.45 mm) opening. I measured my index finger and middle finger together with a caliper and got 1.38" (35 mm), so there should be plenty of clearance in the ring.
I used 2 shells for strength.
If your printer is good at bridging, you might not need supports. I used support type "touching buildplate" in Cura for the stop. I probably could have gotten away with no supports.
I printed mine out of Makergeeks Maker Series Urban Fossil PLA.
I also built in some tolerance for shrinkage. Scaling shouldn't be required, but it all depends on your printer. You might wanna scale it up a little if using a high shrinkage plastic.
After you're done printing, remove any supports if you chose to use them. Mine fit nice and snug right off the printer. Depending on your printer, you may need to do some minor cleanup to get it to fit right.
When I get time I plan on designing a charging handle for the Ruger MK III 22/45 Lite.
There could be a few different styles of handle added in the future.