THOMAST,
Hopefully your question is not limited to hunting with them. I shot lots of the 130 grain 7MM (28" barrel) and the 265 grain .375s (28" barrel).
The first three shot group from my .375-.416 Rem Mag at 100 yards was 1/16". I shot another and the group opened up to 5/16" and one more opened it up to 9/16". I shot a 3/4" group at 300 yards with them.
I compared them to the 260 grain Ballistic Tip for velocity and accuracy. The best I could do with the Nosler is 1 1/16" for three shots. The max velocity for the Nosler in the summer was 2,984 feet per second. The velocity with the G.S. Customs is 3,055 feet per second. I compared them to the 300 partions in one gallon milk jugs filled with water. The 265 grainers went one jug further than the partitions. The most interesting thing about the test was the two partitions went first. When I shot the one G.S.Custom it broke the new 2X6 the jugs were sitting on about 18" in from the end.
In the 7 STW I have only shot the G.S.Customs. They average 3,625 in the summer. The first day I took the rifle to the range I shot six with each one powered by one grain more than the previous load. The six shot group measured 1 5/16" at 100 yards. I settled on the one which was two grains below the sticky bolt. I loaded up six more and shot two more groups. The first was 7/8" and the second was 5/8". The other day I took it to the range and shot one group at 100 yards which was 3/8" and one group at 300 yards that was 1 3/16". The rifle probably has fifty rounds through it by now.
By the way, I tried the barrel break in and not breaking the barrel in. I have not noticed any difference so I no longer break them in.