JGS .220 freebore /.315 neckMost will recommend either PTG or JGS. PTG is more affordable and seems to control a larger market share. It can be spotty getting a response by reports, but if you get David Kiff himself he is top notch.
JGS is run more like a corporate style business if you call in wanting someone else's reamer print they will not share it with you until they call that person and get their permission. Feedback in reamer design was pretty general when I called him.
As far as reamer specs do you plan on neck turning? Others will be able to recommend the proper freebore based on those two bullets. Most likely you will need to pick one bullet to have your reamer optimized, or you can go short and get a throater which requires another step.
I don't shoot the 183SMK so I can't speak to the proper freebore. Common freebore's for the 180 Hybrids are 0.188" and now 0.220" both which may be "shorter" than others will recommend.
Dave manson or jgs.I am interested in a new 284 build. i only plan to shoot 180 berger hybrids and 183 smk. New norma brass. What would be a good reamer.