Snug and firm is all you need. Cranking down tight is not necessary and may actually damage the glass on the jar threads.

Yeah if your lids are bulging or denting then the rings are on too tight. They should just be finger tight no matter what you are canning.

Dave

I am using the ball sure tight band tool.

There is no need for that as it only encourages over-tightening. Half the time it puts them on so tight that you can't unscrew them with your fingers - a sure sign they are too tight.

So just use your fingers to tighten the rings.

Dave

The rings are to keep the lids from falling off. The band tool is worthless and the bands just need to be finger tight. If your food bulges you may have overfilled the jars. Check the headspace for what you are canning.