.223 Rem. one of the best / Ruger - one of the worst ( probably the worst)
Actually Remington was notorious for this as well at one time.
Hence why there are lots of people around that can do a firing pin bushing.
That's the current cure, bushing retrofit, for the rpr 556.
Ruger is being a bunch of dicks and simply shortening the pins on guns that are returned for this issue. It mitigates the signs of the problem, but can lead to inconsistent ignition of the primers. Bigger sd on velocity, and still doesn't 100% fix the problem.
I think it'd be a great rifle if they'd fix the firing pin/bolt, and put a longer throat in it.
A full custom build in 223 is the exact same price as a full custom build in a higher performing cartridge.
If you've got the money to do two or more customs, carry on, but if I could only do one custom, I'd not waste my time with a 223.
Personally, I'd looked at picking up a rpr 223 to extend barrel life on my 6mm insite/surgeon build.
But after running the numbers and seeing the train wreck ruger qc has created there, it makes way more sense for me to roll that rifle/glass money into more barrels and reloading components for the 6mm.