You might try screwing the die down a bit more so that you are putting pressure on the shell holder at the top of the stroke instead of it 'just touching.' Make sure there is zero space between the die and the shell holder at the top of the stroke. You want to use every possible square inch of surface area of that die, especially with a 742, which has weak camming ability during the loading cycle. Some folks even use small base dies for these rifles, altho' I've never had to.
If that doesn't work, I might try grinding the top of the shell holder a bit, if you feel comfortable doing that.