Yes, I've bought about 3 dozen of their hulls and they fit my Parkers perfectly. I talked to the guys there when I bought mine, and it was explained to me that these hulls were designed around chambers of early Parker hammer guns, which MIGHT be different from other guns of the same era. I guess they had a bit of feed back of similar chambering problems, but if I remember correctly it was with English guns, which also had tighter chambers than Parkers.
After I got my hulls I measured them to compare them with the SAAMI standards that are available online. The hulls all fell withing the tolerances specified in the SAAMI print, but they were on the high side.
So yes, they fit my Parker guns (which they were designed to do) I unfortunately don't have other 10 gauge guns to try them in.
I suppose if they got enough feedback, they might consider making hulls of a smaller diameter to fit other makes of guns.
