Barrel break in

[RBriscoe]

Rick....my reamers are made for various brass and headspace is done with fired cases from the previous barrel cut with that reamer. Always fireform....it eliminates the need for 'shoulder bumps' later

Snake,

Compare the headspace of one of your fired cases and a brand new unfired piece of brass. My experience and that of a number of people who have checked is that brand new out of the box Win 7-08 Rem cases (as well as the rest I have measured) is shorter than SAAMI minimum headspace. If the headspace of the chamber in which your fired brass was used was set with any SAAMI based headspace gauge, the headspace will almost certainly be greater than that of new brass. Your practice will work perfectly when using your fired brass with a new barrel and very probably between rifles set up the same way. When and if you use new brass, the first firing, fire forming, may not shoot as well as you would wish and will have to expand to set the headspace "correctly". In my experience, most ram loads wear out brass quicker than the cpt load and so brass gets cycled through requiring new brass to be cycled through periodically. Anyway, your system seems to work for you.

Cheers,
Rick

[boats]

Douglas from the web site.

Run 2 or 3 wet patches with a good bore cleaner through the barrel. Then use a brass brush and wet patch again

Boats

[Snake]

Rick as a point of fact winchester brass is overall smaller than SAAMI...length diameter etc. I fireform by seating bullets out to touch the lands sufficiently to assure that the case head is flush to the bolt face. My fireform loads shoot as well as the finished product...in some instances they grouped better ....that has probably more to do with seating depth/neck tension than any other factor.
Rem brass is thicker and bigger all around but just as short as fresh winchester...Norma is dimensionally similar to winchester but internally heavier ditto for Nosler. Remember that a case with a neck shorter than chamber isn't a problem....the problem comes from too much length. Besides my necks are all 'fitted'.. .310" ...the brass is turned to .011 and sized with a .304 button....thus a loaded round is .306...allowing .002 all around for release. The brass always out lasts the barrel and rarely needs a 'bump'