Finally got the SS barrel from MGM in .500 S&W Mag in Encore, 26" with Pro-Hunter barrel contour without fluted, throated for Hornady 300 gr. FTX. So far, couldn't be happier. Groups inside 1" ALL day at 100 yards. Powder is Lil Gun at 45.0 gr through chronograph is 2390 average with 19 SD so pretty good on consistency. Recoil is OK with Pro-Hunter stock. I will be hunting with it this year in Indiana unless I arrow buck sooner. Barrel from MGM is perfect fit an finish, doesn't foul at all. No copper buildup after 100 rounds so far. The accuracy is even more impressive when you realize it will be used in shotgun zone of Indiana. So much for slugs now. Looking forward to post mortem a buck for comparison to slugs I reload. The folks at MGM were absolutely terrific to work with in setting dimensions and such. Delivery as about 6 weeks. External ballistics stated Dead on at 100 yds and about dead on at 50 yds. Proved out on range as well. Calculated energy is about 3800 ftlbs at muzzle which should leave a mark for sure.
Muddy
Range (yards) Muzzle 50 100 200
Velocity (fps) 2390 2171 1964 1590
Energy (ft.-lb.) 3805 3140 2569 1684
Trajectory -1.5 0.2 0.0 -7.7