I read a lot of debates on this subject, so I thought I'd share some findings with you, based on what my loading manuals have to say. I hear the Lott is way better than the WM because of the 300fps advantage. My findings show only a max of 143fps difference with top loads in each. And most average loads show less than 100fps difference. The other argument is the Lott doesn't have the problem of compressed loads. Take a look at the load densities. They are almost identical in this department with top loads. Here's what my manuals have to say. As you can see, not a huge difference in velocity between the two. The gap begins to widen a little more with Barnes mono metal bullets. Also note the very similar load densities. The Lott takes quite a bit more powder (more recoil) to attain only a small real world advantage. Top loads for WM vs top loads for Lott. Nosler 500gr. Partition WM 2092fps 68gr H335 LD 108%. Lott 2209fps 79gr RL15 LD 109% 115fps difference. Swift 500gr A Frame WM 2116fps 69gr H335 LD 110% Lott 2233fps 80gr IMR4064 LD 105% 117fps difference. Swift 450gr A Frame WM 2292fps 77gr H4895 LD 105% Lott 2378fps 84gr H4895 LD 103% 86fps difference. Barnes 500gr TSX WM 2040fps 67gr TAC LD 105% Lott 2183fps 76.5gr TAC LD 103% 143fps difference. Barnes 450gr TSX WM 2242fps 73.5gr TAC LD 105% Lott 2366fps 81.5gr TAC LD 101% 124fps difference.