I recently worked up a load with the 215g SGK from my custom built 338 EDGE. Did this about a week ago. 102.8g of H1000, rem case, cci 250, 3.720" 3450fps, 3 shots at 100 yards .45" 101.8g shot .8" Now these groups were worked up with fireformed brass and a dirty barrel that hadn't been cleaned in probly 75 rounds, as you can see, still shooting great. I'm at the point where I only clean my guns when they show accuracy loss.
Well anyways, I went home and loaded up 8 shells of that 102.8g of H1000 load and with virgin brass this time around. I also cleaned my barrel. The HART barrel cleaned up very well, within a few patches with some Hoppes BR copper solvent and it was clean.
Went out the next day and figured of course the 1st shot would be out of the group with the squeaky clean barrel. Figured the next 2 would cut each other, indeed they did not!! The 3 shot group now including the 1st fouler was 2.3" the shots are numbered, #2 and #3 were about 1.5" apart. Thought it was me, had a late night didn't get much sleep. Shot my 22-250 a few loads trying to find the sweet spot with seating depth. Got back to the 338 EDGE and figured it had 3 rounds down it, it should be pretty much settled in. Aimed at the middle square and fired 2 shot group #4 and #5. Once again, not good! 1.5" for 2 shots, didn't even need to shoot the 3rd. I had 3 more shells left and decided to try my luck at the 625 yard gong at the range I was shooting at. Dialed up 9 MOA and let the 3 fly. The group was a horrible at around a foot.
Both days the conditions were very good, bout 5 mph wind coming right to left, and shot off a leadsled.
So this got me thinking the only 2 variables that I changed was #1, I used new virgin brass, and #2 I cleaned my barrel.
I dont think its the barrel being clean. It shoudln't take more then 1-2 shots to settle down after being cleaned. Never noticed it with the 300g SMK's, but never ran into this problem either.
Am I right to think the virgin brass is the culprit??
I dont recall seeing that big a difference in group size from new brass vs. fire formed brass in every other rifle I have loaded for.
Your guys thoughts would be appreciated.
First outing, fireformed brass, dirty barrel, = good groups
Secong outing, new brass, clean barrel, = horrible groups