Hi Ben, another over the pond member
. Well I'm not an expert on building guns and also my experience is with euro and hence metric measurements. However I have had a hand in making a fair bit of gear including some guns. If you put "rollergun" into the search function at the top of the page you'll get a lot of info. You will see a nice little rollergun built by my brother Foxfish amongst quite a few others. Good luck to you and ask some more direct questions if you need to after you've read up a bit. Let us know how you get on.
Good Huntin'
Dave
