Hornady,but kinda like the RCBS better form just looking,also have used a Lee.
Couple of things...
Primers and Primer cups can make a difference in How easy primers seat with the handhelds.
1 -Nickel primers like Fed/CCI and older Win are a wee bit bigger than brass Rem or New Win.If one uses them in new cases or cases that haven't had them in them they will seat harder. Had to use a press to seat some federal for a trail run in WSM Win cases one time,zip trouble in once fired factory federal case for the same.
2- Dirty or uneven primer pockets can make some seat harder than others. Make sure the pockets are clean and if you wish,although I don't think it is really necessary get a good primer pocket uniformer.If you do I would suggest the Sinclair Kit Handheld with power tool adaptor.
BTW-It is possible if his handheld uses a spacer/guide for different shell holders like my Hornady does that could play into that. It uses a different Spacer for RCBS shell holders vs Hornadys much easier if you grap the right one for the right brand shell holder :whistle: