zeke, you're most welcome to come over and watch me shoot those groups if you a) aren't tagged "red" because you're a dangerous gun nut
and b) can afford the air fare...
Eastern 7,62mm just isn't.
And that's what all the big boys at the range say too. Many have their Norinco 56's rebarreled with Lothar Walther pipes because of big deviations in measurements in the already over-sized bores - the Saiga barrels are more consistent but clearly bigger than western 7,62s as well, alternating according to one gunsmith between 7,94 and 7,95 mm at the bottom of the rifling. The Norinco bores tend to start up from 7,97 and go to 8,03mm. The Russians and Chinese are generous in both the reference measure and deviations from it in QC...
A local gun rag published the following test groups from their Saiga at 100 meters: Lapua 8-gram 166mm, Lapua ALS 149mm, Norinco 90mm. The bullets measured between 7,88 and 7,92mm in diameter. They also had some surplus ammo stamped LEI (where from?) that went all over the target, bullets measuring 7,84 to 7,85mm in diameter.
Think about your testing through this: with Lapua Nammo you got halfed group size from what? What if you could take yet a third off it?
You're most correct in pointing out the importance of what works in your rifle, that obviously is the point. And, in rifles not made in the third world, Lapua most definitely will work very well, often best.