Well, gee, all the primer manufacturers I�ve talked to say that primer cup thickness does have a great deal to do with whether they recommend them for AR-15 use.
Did forget to mention that, despite what Calhoon says in his article, some primer cups are not made of cartridge brass, and the Tula small rifle KVB-223 has a cup made of copper, so Tula doesn�t recommend it for AR use.
