What kind of groups can you get with your other rifles off the sled? One of the worst things you can do when chasing accuracy is guess. Instead, start eliminating things in an order. It’s like working on an older vehicle that isn’t running right. Start with the cheapest and most likely things first like plugs, wires, cap, rotor, air filter. Then work your way up to the more expensive or harder to change things like distributor, fuel pump, ignition box.
In this case, I’d start with basics like visual inspection, screws, stock fit, ammunition (not necessarily the cheapest right now), torque placed on the rifle. All things you can discover and change. And then move up to the more expensive things like the scope (which you’ve eliminated), barrel fit, action alignment, etc.
Possibly a silly question, but are your bases (not rings) tight?
Another thing....When you load those 60gr bullets, try a dummy round and see where bullet contacts the rifling. You might have too much free bore.