so after the latest factorio update, distant misfires stopped properly working with the vanilla cannon shell(or the 25% range increase they say they have started working with modular turrets(doesnt seem like it after checking)).
ive tried fixing it via the base bullet range but that doesnt seem to be affecting them as i have now have gun turrets that spray way beyond of what the cannons can shoot at but the cannons shells still fall short of their max range with the regular gun turrets going past them now
note this fixes itself when i revert it back to the previous stable version