Camel23-- no offense taken. perhaps i'm a touch hypersensitive coming more from the archery world where everyone monday morning quarterbacks everyone else's ethics. anyway, imho, once you go upwards from the biggest .44 mag loads the biggest thing you gain is trajectory. if you don't care, fine, but it doesn't change a thing in one's ability to kill anything. so in reference to the question i will stand firmly that there is no real difference b/w a .480 and a .475 unless trajectory matters. if so..........then yes there's a small diff.but really not much. imho ruger really missed the 480's real calling by not continuing with the 5 shot 480 alaskan.
a quick comparison
480 ruger 400 grain xtp at 1200fps sighted in at 50 yards will drop 6.4 inches at 100 yards and 21" at 150 yards. this means if you think it's 90 yards but it's 125 yards it's likely a miss if you do your part.
if it's a .475 linebaugh factory load and you're sighted at 50 yards you'll drop 5" at 100 and 17" at 150 which means at 125 you've probably still dropped out of the vitals if you missestimated the range. use a factory 454 240 grain factory load (remember this is deer) and if you still sight to 50 yards and you get a drop of 7.5" at 150 which means you still hit the deer's vitals at 125. now if you sight in at 100 which makes sense for this type of load. (travel will never be more than 1" igher than where you sighted in at) then the drop will be less than 14" at 200.
i've yet to walk and stump shoot either archery or pistols with ANYONE that could tell the difference without a range finder accurately and regularly through washes and senderos b/w 90 yards and 130 yards. the practical difference here b/w a 480 and 475 is not much at all.......because the velocity diff is just not that much but b/w say a 454 and 480 it's big to me where i hunt. if i use my 10" barreled FA83 i get trajectory with less than 12" of drop at 200 which gives me alot of buffer room for small range estimation errors.