A SAMMI spec chamber will have a .2435 diameter freebore with a length of right at .183. After that, there's a 1°30 leade angle over a fairly long transition length.
So, it wouldn't be hard to get faked out using the Hornady tool.
I'd suggest using the stripped bolt method to establish the 'touch point' for the bullet. Then, with the same bullet, try the Hornady tool and compare the two.
Good shootin' -Al
