I suspect the bean counters at Ruger are also the responsible for their the second rate PCC barrel liners.
Thread drift due to incorrect information. ^
I just got off the phone with Ruger.
You are incorrect. The PC Carbine has a solid, one piece barrel, there is no barrel liner. Call them yourself at 336-949-5200 and ask if you don’t believe.
Threaded barrel showing it is machined from one piece.
Rubber O ring
Stepped thread protector to clear o ring, this can be used in either direction so it is stepped on both sides.
Reversible thread protector in place.
You said something happened to a gun you own or were around. Whatever the damage is, it wasn’t because of a barrel liner.
Show some pictures and somebody here can help diagnose and get to the bottom of what happened.
As to a new pin or spring, both can work. The pin is probably the better option if you shoot hard primed rounds pretty much all the time, they were about 80 bucks the last time I looked. If you pierce soft primers you may etch the bolt face from the hot gasses escaping and over time cause damage, look for that if you shoot a lot of each.
The spring was about 6 bucks. They are in stock. The same soft-primer caveat goes with these, plus as posted above there may be an issue with broken pins from the extra whack the hammer delivers. (Anything like that is certainly possible.)
Stay safe.