Too many variables,
1 will a large heavy barrel be more accurate with a rigid receiver? YES
2 how would a less than solid rec.influence accuracy . Everyone is still working on this one but stiff is better than flexing
3 are you a good enough shooter to notice any diff, ( not to be rude but most likely not ) usually what u believe to be better product will produce better results.i have assembled military mauser shoot 5 shot groups that consistantly shot .078 @100 yards.
4.a solid top steel mount 4 # 8 screws and pinned then trued would be all most of us need.
5 axis actions are very rigid
6 to test , mount rec and barrel to solid steel bench ,attach mag laser to top ,add 20# to end of barrel,mark laser mark on wall, remove weight note laser level .amount of change? Dont expect inches ,just maybe a few thou.
It doesnt matter what action u test with the amount of flex would change with receiver design