Hey, guys good day to you all, I need a little help. Planning to make a hybrid speargun with wooden barrel and a euro plastic handle and reciever. Looking to purchase a handle for Omer Cayman, trying to findout what is the outer diameter of the part that you insert in the barrel.So that I have a clue what router bits I will buy. If you guys have any or any other brands, can you please post the diameter of your recievers. Maybe it's time to clean those barrels, maybe this is a good time to clean it as well. Thank you in advance.