My Bach 42B fits in my SKB462, but the bell portion of the case needs to be squeezed close together and then latched.

Is this normal? I feel uneasy squeezing the case shut as it probably squeezes the bell.

Does it only do it with the instrument in place? Sometimes it's just that the case rim/valances don't quite line up.

Otherwise, work out where it's grabbing and compress the interior foam to relieve. If you put in a sheet of newspaper or similar before closing you can probably recognize the area(s) of maximum squish.

I'd be surprised if there isn't more than adequate clearance for the bell itself; it's probably just wrap tubing or the trigger digging in.