Since RL26 is non-existent, and I have personally seen big pressure spikes above 85°, and it routinely hit 85°+ in AZ on several of our hunts for pronghorn, and early deer/elk, I opted to try some RL23.
I use H1000 and CCI BR2 in my personal 6.5SS with 140 HVLD @ 3140 and 150 SMKs @ 3117. I have loaded for a couple others with similar results using the same components.
I got a 6.5SS that was not liking this combo.
For mine, and others, it was very close to the same build.
Same 26" 1:8" barrel length/twist
Same ADG brass w. Same weight range
Same case dimensions after fire forming
Same CCI BR2 from the same brick of 1000
Same H1000 from the same 8# jug
Same 140 HVLD from the same 500ct box
Mine, and others, get around 3140fps w. 58.5gr H1000 and 140 HVLDs. The latest only got 2950fps.
Well, we don't build a 6.5SS to run 2950fps. So I had to switch it up to try and get some more speed. Accuracy from the Axisworks built rifle was superb at 2940ish, but we were feeling the need for speed.
ADG fully formed 6.5SS brass
Fed GM215M
140 HVLD
2.230" CBTO
RL23:
54.5gr @ 3061fps
55.0gr @ 3068fps
55.5gr @ 3093fps
56.0gr @ 3118fps
56.5gr @ 3141fps
57.0gr @ 3166fps
57.5gr @ 3201fps
BR2 & H1000:
55.0 @ 2870fps
56.0 @ 2908fps
57.0 @ 2920fps
58.0 @ 2940fps
58.5 @ 2952fps
If you are not getting the speed you want, or are having a hard time finding RL26 (or worried about temp swings), try RL23.