I don't know allot about 3D printing but know allot of the 3D items look like they were whittled with a butter knife. ( Read: Butt Ugly!)
Often that's because the maker either doesn't know how to model or uses something that's limited like TinkerCAD. Or their slicer profiles and/or machines aren't dialed very well.
I've had a few requests to print some of these CZ things from Thingiverse and usually they don't work as well as I'd like them to. If there's something I need I much prefer to model it myself. That way I can make it look and function how I want it.
IMO bore guides should be made of Delrin or aluminum but sometimes they're not available for a particular rifle. Printing one is a good option as long as it fits the action and cleaning rod properly. 3D printed items aren't necessarily leak proof either. So that's something to consider when modeling, slicing the model, and printing. You don't want solvent leaking into the trigger group. I have a really nice M-Werks bore guide for my 10X X3L but I wanted one that stops at the loading ramp like the PQP one does for my 2500X. So I made my own with two different rod inserts that fit both of my cleaning rods like a glove. It stops about an 1 3/4" from the chamber yet the rod lines up beautifully
BTW, the rifle's sitting in a 3D printed cleaning cradle
I also wanted rod guide inserts for my PQP bore guide to fit the rod a little more closely. I made a couple for my Pro Shot rod and my PQP cleaning rod. I printed them two different colors. So I know which rods they work with
A couple guys asked me to make the bolt block things for Anschutz and CZ. As a RSO I'm not real big on them but I went ahead and modified the single shot adapers. They work well but I prefer people use chamber flags so there's no chance of leaving a round in the chamber. I see people calling them ECIs (Empty Chamber Indicator) which is wrong since a round can still be in the chamber
I needed a case to put my ATS tuner in. It fits like a glove
A RFC member and popular gunsmith needed a couple trigger guards for light weight builds...
I can go on and on but the forum software says I've overstayed my welcome lol. I've posted most of what I've made in the BR chat thread and a couple other threads. You can see some other things I make in the classifieds section