If you don't need to take your scope on and off, I suggest Talley LW. No need for steel even on the 300wm. I have talley's on my winchester 300wsm and Kimber Montana.
I have steel weaver's on my A7 but will change them out eventually.
If you don't like the Talley's - take a look at DNZ - they have the one piece and now two piece that fit the A7. I have the one piece and am very pleased with them on the A7.