so, to sum up what i've gathered: packages of DR Legend state in 2 different places on the back, "round core" and "hex core", and some TB member says he got word from DR that the "hex core" part is an error. so. round core.
i just got a brand new set, and first off, i measure them w/ a micrometer. b/c that's what i do w/ new strings.

now, in the past, i've found more often than not, DR strings like Hi Beams and Sunbeams and Lo Riders measure up about 1 or 2 thousandths of an inch smaller than they claim to be. maybe they do that on purpose so their strings feel ever so slightly easier to play.. but if they do it on purpose, it's deceptive and not cool... anywho, the Legend Flats, which claim to be 45, 65, 85, 105, actually measured to be 42, 61, 83.5, 105. am i wrong to be a little pissed about this? these gauges are almost identical to light gauge La Bellas DTB... if i wanted that gauge, i would have just gone w/ the La Bella... i really wanted to see what a round core, medium gauge flatwound felt like..
so, has anyone bothered to measure their DR Legend Flats? is this a fluke? i doubt it, but the D being a whole 4/1000ths off.. that's bad...
oh, and w/in 24 hours i can see slight separation of the windings on the E string over the 3rd fret. boo!
on the positive side... they are super easy to play, w/ my neck set flat i can fly around and play just about anything i could have on rounds. haven't gigged them yet, however... may just live w/ them awhile if they work on the gigs and if the windings don't separate any further...
i already complained to DR, am awaiting a reply. may just go back to a 45-105 set of LaBella, as that's the gauge i really wanted, and i know i love those strings in their 49-109 set.