All current production gas checks in all calibers sold under the Lyman and RCBS names, are made by Hornady, to Hornady specs. Gator 41 checks are excellent quality and fit also.
Beware that many gun shops have old Lyman 41 caliber checks in stock, because the caliber is a slow mover. The old style, which will be loose are yellow brass, rather than the copper color of new production.