1/2" copper but what "type" different types have different ID`s. 1/2" type "L" is .545 ID, type "M" is .569 and so on.
Thank you for bringing this question up Shooter.. I forgot to say that the barrel I made these for is 1/2 inch type "L" copper
.. But if you are in need of something different contact me,` the size of the head and the tail can be changed with relative ease
Also I would like to see some distance and accuracy testing results before I commit to $20.00 + shipping.
That is fine, I will say that it could be some time before I get a chance to do any testing.. I don't currently have any airguns that work the way I would like them to and their accuracy is not up to par because of the trigger mechinisms.. But I will try and get one going and test these out extensively