first question. i have a custom 7mm mag built on a argentine mauser 98 ,09 action, 26" barrel...super, super accurate..i mean like out of the ordinary accurate...here is the deal...i also owned a 7mm in a savage. This custom gun will NOT! chamber shells that were shot out of the savage. And it's really hard to full length size them enough. The only way i can resize them enough is by adjusting the sizer die down so far i can barely cam it over when i run the case up....The thing that baffles me the most is i bought a couple boxes of new Rem ammo that chamber in and out perfect...Why am i having such a hard time sizing cases that were shot in another rifle? The new empty's shot out of the custom chamber fine and will require nothing more than neck sizing... baffled on the resizing second question if this custom gun has that tight of a chamber...will the pressure be higher for any given load?..using less powder to achieve the same velocity as in say the savage? i haven't spent a lot of time with this gun yet..it also has a stock that don't fit me very well..(see thread in gunsmithing)...but i need to get this rifle up and running...shoots way to good to be sitting around.