you may have to drop down to the 129s to get the speed you are wanting.
In my old 26" .260 Rem, I ran 140 VLDs.
Lapua LRP brass
CCI BR2
42.5gr H4350
140 HVLD
2850fps
Sounds about right Lance, especially in a 26" gun.
Looked back through the notes written on my bench and it was indeed 42.5 grains of 4350 behind a 139 Scenar for 2765 in the 20" CTR.
I also had a 22" Rock barreled .260 that ran 140 Amax at 2825, 42.5 grains of 4350 in that one too (all loads also in Lapua LRP brass).
Yeah I figured the 20 in barrel had me hand cuffed. I shot 3 rounds loaded with 43.3/ H4350 with not even an ejector mark. I'm gonna bump it .2 to 43,5 and just roll with it as long as there are no pressure signs. Based on what Ive seen so far that should get me to 2600ish......my longest shot is 400 yards but typically 300 or less.How far is the typical max distance shot where you hunt? If 300-400 or under, that 2550fps will be plenty.
I wouldn't go any more over 44gr H4350 with a 142, actually I wouldn't go much over 43.0 if it were me. You have got to be at max.
You might want to go get about 100+ rounds down the barrel and get it broken in. You should expect about 100fps speed up from new to 100+ rounds down the barrel. Also, 2850 in a 26" will be about 2700 in a 20". You are asking an awful lot out of a 20" pushing a 142 @ 2800. Try RL26 if you are trying to wring out max velocity.
Looking at your numbers, .4-.6gr of additional powder are not going to get you 200-250fps more anyway.