Pretty sure his Allen Xpress line are Lapua improved, The allen Mags down to the 338AM are cheytac improved(505 gibbs)
Yer right!
There is one exception that I was thinking of and that's Kirby's Raptor line and specifically the 338 Raptor. The 338 Raptor is, to me, a very promising chambering as it rests between his own 338 Allen Xpress/the 338 RUM/338 Edge(and +P variant)/the 338 Lapua(and AI variant) and the HUGE 338 Allen Magnum.
http://www.longrangehunting.com/forums/f19/allen-precision-338-raptor-update-93203/which is based on the 338 Excalibur (which is/was "an entirely new case") designed, I think, by Jamieson Int'l.
http://www.broadswordgroup.com/338_excalibur.htmland *not* off the 404 Jeffries. My error.