Re: M1A G.I. parts vs Non GI...Does it matter?
I think it's a matter of personal preference. Some folks are simply more 'purist' than others.
I used an M14 in 'Nam, and gave it relatively tough usage. Never had a malfunction that was serious enough to recall at this late date; so USGI parts are clearly satisfactory to my limited knowledge.
I also owned a S/A 'loaded' stainless M1A, New In Box. Not sure what origin the parts were, never really looked, and I shot it a lot with handloaded ammo back when I was learning my handloading skills.
Yeah, I could make it fail, but the failures always turned out to be screwups on my own part, and not the gun's. It's my personal opinion that if you can make a part fail on an M14/M1A, it's at least as much your fault as the part's.
When I do model airplane design, failure is part of the design process, and little more than an opportunity to improve the design. I think the basic Garand/M14/M1A design is well beyond that part of the process.
Greg