The Gator gaschecks come in 3 flavors for the 41:
1. 410-397 meant for Lyman shanks of 397 diameter. Meant to be
sized to 410. This check is paper thin because the shank is so
large.
2. 410-378 meant for NEI, MM molds, or those having a shank
diameter of 378. Meant to be sized to 410 or larger. This check
is as thick as the case neck is on a 308W. This is the go-to
check for any custom mold ordered. About all of the commercial
castors use this check.
3. 416-393 meant for the 416 caliber rifles, where the boolits are
sized to around 416.
4. All of these checks are the crimp-on type, and the crimping ridge
is quite substantial when compared to Hornady.
... felix