..."assuming same barrel length, the 338 LM is within 140-200 fps from the 338 WM (same bullet weight)."...
unless you are talking 300gr bullets. in my mind, by far the best offering in 338L.
below from:
http://findarticles.com/p/articles/m...6/ai_65574867/
..."With due credit to Winchester, early factory ammunition was loaded very close to advertised velocities from the 25" original Model 70 Alaskan. Winchester's loadings consisted of a 200 gr. Power Point at 3,000 fps, a 250 gr. Silvertip at 2,700 fps, and a 300 gr. Power Point at 2,450 fps. What's more, the ammunition shot with impressive accuracy The average Model 70 Alaskan .338 turned out to be a real tack driver."....
below from:
http://en.wikipedia.org/wiki/.338_Lapua_Magnum
9.44 g (300.0 gr) Lapua Scenar GB528 VLD 837 m/s (2,750 ft/s) 6,810 J (5,020 ft·lbf)
above from an accuracy international, a 26" bbl. the extra inch won't account for the increased MV numbers.