Loaded H 4350 into Hornaday brass with Accubond 140gr bullets. 3 rounds with first shot cold barrel. Sub 1/2” moa at 88 yards.
Same brass and bullets with RL 15 was almost a 1” mod at 88 yards. One round could have been a flyer as first two were a two shot same hole at 88 yards.
Still haven’t gotten a ship date on the RL17 but my Lapua brass should be here Wednesday. If the powder comes ill load up some rounds and test this weekend. If that powder works, apparently is more temperature friendly, will be a good thing. If not I may have to find someone who wants it.
Did you get that just on the first load or did you tune the load for your barrel? I usually break in a barrel with a series of loads for one or two of my preferred powders and load nine or ten rounds of each ‘load’ to get three good groups to measure for each ‘load’. Its a more effort, buts its also an excuse to shoot more. :)
So for a given bullet weight from a given lot (usually seated 10 or 15 mm back off of ogive), I might load and shoot ~45 rounds (3 groups of 3 each for a ladder of 5 loads from min to max load). I keep records for each gun so I know what works best for any given bullet type, and a given powder. Its interesting to see how the barrel harmonics can appear out of nowhere in a given ladder.