Cramer (Sako) or Star Lubersizer for gascheck bullets??

Please forgive me if this has been asked before, but I can't find it.

I have an older Cramer lubersizer that hasn't been used in many years and a Star lubersizer that I am currently using for plain base bullets. I have been informed that "you can't seat gas checks on a star". I have also read that Laithsmith makes cupped punches close to bullet diameter for the very purpose of seating gaschecks.

I would really like to use my star to seat gas checks and I would like to hear from folks who have done it. I'm looking at bullets for the 300 blackout. I have a few Cramer .310 molds and I am looking a NOE molds designed specifically for the blackout. I understand there are a few molds designed for the 7.62 X 39 that work well in the 300 BLK, 300 whisper, 300/221.

I seat gas checks on my Star all the time just fine. I mostly use Gator checks that are slightly domed inward and the Star makes the checks absolutely flat! The only cupped punch I got from Lathesmith is for .375 just to try, but I much prefer a flat one.

I also use my stars for gas checks however if you are checking really pointed bullets I use a dummy one with point filed down between each one. The 150 gr
blackout mold that we use works fine bullet to bullet.

you can't?
crud,,, I need to sell one of mine then.

I just do one of three things.
A. I drop the boolit in the sizer and set the gas check on the shank then press the handle.
B. I set a thin piece of steel on the sizer and use the punch to press the check into place then flip it over and push it through the sizer.
C. I push the boolit and check through base first without lubing then flip it over and add lube on the second pass.

I prefer using the Star to seat checks.