The length of a shell is determined by its "Fired" length. Thus a 2 3/4" shell will be 2 3/4" or close to it, many are a little short, irregardless of crimp type applied. A loaded 2 3/4" fold/pie crimp shell is shorter than a 2 3/4" roll crimp shell. Many, but not all by any means, of the older roll crimp shells were 2 5/8" length. Some years back I fell into the long cone theory & lengthened a few, But Never Again will I do this to an old classic. Most of the advantages of the long cone were simply dreamed up to sell reamers & cone jobs.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra