I will try to feed some through my 700. Dave, my smith hates the Remington for feeding the Ultra mags though. He said the magazine box is too narrow to start with and they ignore the formula to figure the rail width, length and shape. They just did what they could to "make" it feed. His suggestion I know would be to use a Winchester M70 as was his when I bought my 300 Ultra too. His opinion is you cannot count on them 100% to feed the fat case designs. They jump out of the action etc. I have'nt even fed any out of the mag yet with mine, only top fed at the bench so far.