Definitely over 3". It's a big chunk of steel. Sounds like what you may be after is a 11" STF/12.
Hey ST1264, pm me a reminder and I can measure it when I get home.
We have no large primers, but we will have some small primers left. 10,000 is the max per person.
If you email me or websales your name and phone #, I can check what they pulled for you and follow up.
JR