It looks to be a difference of about 0.519" long for the #17 and 0.574" long for the #11 in terms of the length of the tool from the reference shoulder to the bottom of the tool.
So in terms of what that does, they hold those necks at different heights in the coil.
The .308 & the 6.5 have a different pilot.Same with all the .308, 30-06 and 6.5 CM family of cartridges - as long as the only difference is the neck diameter, parent case and off-spring will use the same pilot.
Yes Sir - what I meant was, all the different cartridges that spawn off the .308, 30-06 or 6.5CM (and there are many more example family trees like that) will have the same pilot (as long as the overall brass length is the same). So the .308, .260 and .243 (to name a few) will all use #11, and the 6.5CM "family" -> 6.5CM, 6mm, 22CM, 25CM and whatever else is made from those cartridges will all use the #17 pilot as long as their overall brass length are basically the same length. If a new cartridge is made with the 6.5CM as the parent case, but the resulting new version is shorter, it would use a different pilot. Obviously, the 30-06 family will also have a completely different pilot than the others mentioned. It's about brass length (mostly) with the pilots, vs head dimensions for shell holders.The .308 & the 6.5 have a different pilot.