Gregg--Glad you found that book.That will help for sure, you guys building break actions from scratch..Mickey's
Imperial case is 4.25 also, but a .983 bore.Ross' Evans
is .975 and 4 in long.The longest I will be able to make is
4.1 in. And I would prefer to make them as big bored as possible to keep the side angle right...IE if bore is
in the smaller range then base should be smaller, but to make base smaller to match smaller bore takes a hydraulic press and 2 inch dies.And subjecting the case heads to that
extra working shortens case life.If they can be done with my present, no huge strain process, these case in regular 4 bore loadings will never wear out.Even higher pressures they will go a hundred rounds(30-40K).My personal favorite
is an inch, but making it .983 to match Imperial would still give be within specs, to give it
the right slant to the sides, and case could be still used for folks having the Imperial chambering that London Guns made for their run of 4 bores...The 4.1 case
would fire in 4.25 chamber fine.Being this development
process is slow, your friend will probably get going
as fast as any others needing barrels.And him starting out with a 4 bore, and not having huge investment in hundreds of other tooling, won't be too bad.IE others are reluctant to do new stuff , because they have so much invested in
tools for their present sales, to want to add something new..Ed.