Grizzly - the Lott chambering is different from the Watt's chambering, in that there is no 90 degree shoulder at the chamber's case mouth with the Lott as there is with the Watt version(of the 1950's). Otherwise they are about identical.
: Lacking the sharp case mouth inner shoulder, the Lott chamber's smooth angles allow shooting ammunition that is much too short for the chamber, ie: .458WM. You could shoot .458's from a Watt's chamber, but that sharp edge would or could shave jacket material as the bullet passed over it. Subsequently, you would probably not be able to chamber a proper length loaded round, and that jacket material would be difficult to remove without a chambering reamer.
: With the Lott's smooth transition, there is no shoulder to catch and grab the jacket, and the bullet is allowed to rattle itself into a fairly correct line with the bore's axis as it is squirted down the barrel, apparently with satisfactory accuracy.