Quote Originally Posted by maximus View Post
Does the barrel end get machined to form the hole for the tap or does it bottom in a counterbore with a short plain bore in front of the tap? Either way has serious problems to overcome. If plain bore before barrel it would need opening out to .25 and would thus be irreversible. If it forms part of the bore for the tap then the radius would have to be machined after the barrel was fittedwhich would be nigh on impossible to do and retain the tolerance for the tap. I think its a non starter for a tap loader personally.

Regards Max
Hopefully here's a link to one that's been removed.

https://www.airgunspares.com/bgwt019...22-barrel.html