The WW AA HS hulls are 2 piece with a plastic base wad. If you look inside with a light and compare with the old you'll see. They load the same as the old style maybe some minor adjustment to you loader but components and data the same. I for one have had zero trouble with them. You are sure to hear like wise form others
Hear likewise from others such as me who can't for the life of me find out how to the get things to load right...I've tried multiple different wads and they almost always come out with a ring about a 1/2 inch up from the brass where it wrinkled. I've got about 750 of them left and as soon as they are gone, I'm switching to STS's as I've loaded quite a few of them and haven't had a single problem. JMHO
I've had very few issues with the new two piece Winchester hulls. There have been many accounts of base wad migration/separation. I've never seen it myself and I've loaded many thousands. I've seen base wads in RIOs and Kemen hulls migrate up a 1/4 inch or so, but never one of the new AAs.
Jolly, the issue with the buckling in the case tube above the brass is usually resolved by adjusting the crimp starter downward until the hull has an opening smaller than a pencil eraser. I get it almost down to about 3/16". The other issue is that the crimp die needs to be backed off and the final taper should not be set too low either. The MEC presses can be adjusted easily by backing off on the crimp "cam" a bit. The buckling sometimes is more noticable with longer wads like the 1oz and 7/8oz Winchester wads and clones. A quick call to your press manufacturer will usually get it fixed quickly.