First thing i would do is take the gun to a very well known (gunsmith), not just some wannabe, and have it repaired and thouraly checked out.
Next i would be reviewing my entire approach to loading, including an honest evaluation of my own ability, and what my goals are for shooting.
Despite what we read on the internet, the basic reloading dies sold by makers like RCBS and Lee are very good and capable of producing loads beyond the shooting ability of most of us with modern factory rifles. Who ever started the notion that accurate loads cant be created with full legnth resized cases should be exposed for what he is, an idiot. Read the manual that comes with the dies when you set them up and thats it.
Ive been loading since ive been 15, and im now 85. Ive never owned a comparator, and dont see the need to have one. Finding the OAL of the cartridge is as easy as closing the bolt on a partially seated bullet and adjust the die till you get the desired length.
What else is necessary for us to have than that?
I agree that a good set of calipers is nice to have, but fact is they dont have to be professional quality.
If we keep a dummy round of the load, and an empty case of the proper length, then it need only be used as a gauge to compare length.

Now if we want to become another cat chasing his tail with regard to even smaller than necessary groups, then we just dont skip over the basics and start at a higher level because of the way we go about loading ammo, like neck sizing only for example.
The old cliche of trying to create a silk purse from a sows ear still applies, and it no doubt always will.