Stud Fitment in Cast Iron Drums

[Mike1291]

I had new cast iron drums put on my original hubs recently by a machine shop. I noticed that some of my studs were loose when I was taking off a wheel and it appears that all four drum/hubs were affected with loose studs. It appears that the stud shoulder is not all the way through the drum as I see in other reference pictures.

I have a friend with a press and we tried to see if they'd go in any farther but no luck.

Is it possible that the wrong type of studs were used (ones for original stamped steel drums) or that the stud hole in the drums are not correct?