From Fourarmed's post I see that I'm not the only one flaring Hornady gas checks to fit them properly on Lyman shanks. One each in 25 caliber and 30 caliber need that little prep step. FWIW, the 30 caliber (#311291) needs both Lyman and Hornady checks to be flared.
None of my 41 caliber molds need gas checks--can't help on that subject. I'll shut up now.