I wasn't advising 55 gr. bullets or heavier in a 1:7 twist because of accuracy. Very light bullets in a 1:7 twist rifle can end up spinning so fast that the jacket completely shreds off the bullet due to centrifugal force. Sometimes it looks like a weird flash in front of your muzzle, but the way to tell for sure that the bullet came apart in mid-air is by the odd holes in the target.
An over-stabilized bullet can have issues at longer ranges. Sure, an over-stabilized bullet is a heck of a lot better than an under-stabilized one, but at longer ranges a 50 gr. bullet is going to work better in a 1:8 or 1:9 rifle than in a 1:7.
At home-defense ranges over-stabilization is isn't an issue, but the jacket separating in mid-air due to the bullet spinning too fast can be a problem. That's why I advised that if you have a 1:7 barrel you should test any home defense load that has a bullet 50 gr. and below, because jacket separation has been know to happen in 1:7 rifles using those bullets.
0331: "Accuracy by volume."