I was getting my hatsan 125 tuned and the tuner called me and told me my barrel hole is over sized. The pellet fits snuggly in the breach but after that the pellet fall through til the end of the barrel where it gets tight again. Kind of like a choke. The tuner said the barrel is so over sized its actually slowing the pellet down. He has experience with hatsans and says if I buy a new barrel from them there is a big chance I'll get another bad barrel. What would be a good fix for this? Are there any airgun barrels for these that would fit it ? I need recommendations.