The trigger on my gun is ok except it stacks badly just before let off. Trigger pull is 7 lbs for most of the pull but the last 1/16 of a inch it gets very heavy. It is not consistent, sometimes it will go to 10 lb or 12 lb and even 14lb. If I pull the trigger quickly it does not seem to stack. If I pull it slowly,like when trying to shoot a group, it really stacks. Has anyone else noticed this problem with their gun?