RE: the Hornady 139 gr. GMX, I ended up using the Hodgdon data from their 2018 Manual. Their max load is w/ IMR 7828, 70.0 gr (compressed) @ 3191 fps. These are for use in a "rode hard, put away wet", mid-60s Rem 700 BDL (with the black copper and iron plating SS barrel) I picked up from a friend. I did put a Hogue Comp-stock on it (I'm a recoil wimp) and didn't cut my eye on the scope). I used IMR7828SSC and Fed215 primers in Win brass. I started at 65.5 but only got to 68.5gr. with very, very flat primers @ 3176fps. 66.5 of 7828SSC had a much less flattened primer @ 3100fps. At 50 yd. (my range's 100 yd. alley is out of action now), all but one of my mini-ladder loads were in an inch group. I think this Rem 700 has potential ! I can hear the choir saying "try Re22", and I will later but they don't list that powder in the Hodgdon Manual, nor does Alliant list the GMX projectile...I also intend to try the Barnes 120 TTSX w/ Re19 in the next round. Will check in with that info later.
