Here is a small collection of thread protectors threaded 1/2-28 in multiple diameters and lengths.
No post processing necessary, if your printer is calibrated and tuned well then these should thread on like butter. If they are a tight fit on your barrel you can always quickly chase them with a ½-28 tap.
I print these out of eSun PLA+ and they have held up well for slow rimfire applications. I will also print a few for my barrels in storage and the parts bin to protect the threads. You can always print out of higher temp materials to handle longer strings of fire and barrels heating up.
These are split into three categories right now:
The file names give a quick description of the dimensions of the model:
“ThreadProtector_0.5-28_0.750D_0.6L_Knurled”
Match the diameter of your barrel and length of your threads to the best fitting model. The protectors are 1/16" longer than stated in order to protrude past the muzzle and give further protection to the barrel crown.
If there are any additional lengths, diameters, or thread dimensions you would like to see, please leave a comment and I can add more as requested.
I modeled these from scratch in SolidWorks. The threads are modeled to exact Class 1 dimensions and are a perfect fit to a barrel threaded to Class 3 dimensions. I modeled to the looser class 1 to account for the FDM process and give the best chance of an easy fit without having to chase threads with taps.
EDIT: I also just uploaded a STEP file with no pattern on the outside an a 0.75" OD for easier integration into your own models or your own remixes. Use it for blast cans, solvent traps, comps, or other stuff you need threaded to a rimfire gun.
The author marked this model as their own original creation.