If you address the rifle and you find every time you
"Check" the bubble on your rifle (for those that use one) and it's off or canted, that is a setup and training issue, something we like to call a clue.
for the proponents of levels, imagine this, Every time you sit in your car, the mirrors are off, you can't see correctly out of them. Do you set them or move you? That is the issue with a level, if every time you view the level and you are off, that a fundamental issue going wrong, and not something you just fix by shifting your body. Clearly, you are seeing it off more often than not, so that should tell you something about the set up the rifle.
These are cheap ass $6 levels with barely any real-world accuracy put into a $150 wrapper under the guise that you need this to shoot straight. Well, you are being sold a bill of goods and not the correct ones.
A level is a training tool unfortunately 95% of those with them have no real training and think looking it at it is how they work. No, they teach you to understand rifle set up and your body mechanics.
Cant comes from several places and most of those places are subconscious, which means it happens without thought or effort. Your body is steering the system and you are oblivious to the changes happening. The main driver of cant is from running the bolt itself because the bolt is on the side we pull the rifle over in ever-growing increments until we "notice" the issue the and fix it. We see guys string groups even at 100 yards because of it. I can look at a group and tell who is canting the rifle each time and who is not. The fix is the bipod and not a level.
A loose bipod that tilts is the issue more than a level.
Other issues are cheek pressure, and not supporting the back of the rifle properly. Too loose a hold or no rear stock support you are holding the bag and not supporting the stock.
Being sideways even a little and rolling your head over, screws up our fantastically accurate balance system in our head which is a lot more accurate than that cheap ass level on your rifle. Our own Vestibular system is awesome, why not use it,
it's not only a liquid system, but it also has micro fine hairs to work together.
Super Accurate, what level out there works to this degree. Answer, None
Canting with a rifle is a training & setup issue more than anything else, it's not a shooting consideration unless you are taking shortcuts and make it one.
This needs to be done without thought, like breathing.