First, yes to the question about some manufacturers SEEMINGLY have better consistency in their high end offerings. CenterX comes to mind.
When I buy a new lot, it's definitely a crap shoot, but I buy 5000 rounds. Then I open 50 of the individual boxes and take a round from each one, replacing the missing round and closing the box back up with one from a dedicated box. I shoot the 50 and pray for good groups. Sometimes it's obvious with the second magazine that this ammo is not right for this rifle. That's ok...my LGS will take the good stuff as trade and we do this sort of thing once in a while. Or I might keep it for plinking ammo...which is all i really do anyway since I don't like to compete except for beers and bragging rights. Or I might relegate it to the 10/22's or I might give it to the families youngsters to go shoot red eared sliders.
If that box of random 50 pulled from that random 5000 rounds does shoot good, I try to find more of that lot. I have never found more of that lot.
I only have 2 B14R's. Those are my accurate 22LR's. I have several 10/22's, a Ruger American, an old Springfield M2 22LR some old Remingtons and an old Winchester and 3 old Browning autos. None of the old rifles are quite as accurate as the B14R's except that Springfield and mostly collect dust. I do keep them cleaned and lubed. Anyways, I'm not that great of a shooter is my point and do not have the real high end 22's.
As for weighing rounds, there is documented evidence that measuring rim thickness is worth doing. l don't. I don't weigh, I don't reshape. I just shoot stuff. Again, I don't formally compete. Fuck that. I like to shoot so I don't want to make it competitive and start working at it too much.
There are some true 22LR experts here that have tons of write ups on this forum. One is
@justin amateur
EDIT: I mostly shoot CCI Standard Velocity. It's real consistent for me. I am shooting the heads of grasshoppers at 40 yards with 9/10 hits. Now, if I am going to shoot against my brother for beers, the CenterX comes out and he doesn't have any...HAHAHA!