Winchester brass is lighter in weight(more volume) and harder than Remington and will take more pressure.
Winchester takes more powder for the same velocity as w/Rem brass.
Plus I can get more velocity out of Win brass which tells me they are a bit tougher than the softer Remmy stuff.
Your numbers don't indicate very much expansion after firing. A good thing.
What's the measurement after resizing? Excessive resizing could be a contributor?
I'm thinkin' J E Custom may have some thoughts on this topic. He's a seasoned rifleman with years of experience. Give him a PM as he probably hasn't picked up on this thread.
Getting that number as firings out of a case isn't unreasonable for me. I get about 6 out of mine but the primer pocket is the problem.
I'd be concerned about what gas flow does to the chamber in your situation. Not good I'd think.
The erosion ring around the firing pin hole is pretty bad. J E said it was the worst he's seen. Typical for me.