I finally got an 8 lb jug of Reloder 26, too expensive but oh well. I'm amazed at the velocity I can get out of my 6.5 CM with this stuff. Today I shot 2 ladder tests using Berger hunting bullets. One was 156g EOL and the other 140g Extreme Hunter.

The interesting thing is shots 2 and 3 with the 156 EOL keyholed. I was suprised as I've used this bullet quite a bit and never had this happen before. Barrel is 24" Douglas Premium Match 8" twist and it's generally very accurate with the 256. I know Berger's calculator says it's marginally stable but accuracy has been outstanding.

I think I'll stick with the 140 Ext Hunter, its not quite as accurate as the 156 but still shoots about half moa, sometimes a little less. I think shots 6, 7 and 8 are my node.

What do you guys think?

Might want to verify your barrel is a 1/8 twist by measuring. They do vary in button rifled barrels so it may be a 1/8.25 or so and that’s why it’s key holing with 156’s ?
You asked what we think so here you go. I run 150’s with Reloder 26 from same length barrel so have some experience. Running 140’s at 2960fps is doable as you have shown but try that with say Hornady LR primer brass and see how many loads you get before you loose your primer pockets.
Lapua SR cases do a great job of masking excessive pressures which I also have experience with. Just saying.

There are others on here with much more experience than I, but I see shots 1 and 2 as your best node. My best load with h4350 is about 2800 fps with 143 eldx. (26" barrel) I did hit pressure signs slightly above that. I know, different powder and different bullet, but still. 2950fps is pretty dang fast for a 6.5CM.

Thanks DStround, I'll measure the twist. I know it's hot but brass looks good bolt lift wasn't heavy.

unclbubba, yeah I was thinking to do further testing with loads 1 & 2 also.

Next steps are to try seating the 140s to different lengths. I'll test 46.4 and 48.4 grains.

I just measured the twist an it is indeed 8.5", I guess that explains the 156g keyholes.

I would work around #1 and #2.

The rest is quite hot.

Shoot those larger charge loads in +90° weather and I bet really bad things are going to happen.

There's no real point in pushing a 140 gr super fast in a 6.5 Creedmoor. At 2800 fps, I've hit 1400 yard steel with them.

Dstroud knows his chit!!

Traditional pressure signs like case head expansion (especially, even though some are convinced it's a viable method), primer appearance, bolt lift, etc. are not to be ignored, but they are not a good reliable way to estimate pressures. Often they will not indicate a problem until you are way over 65 kpsi.

If you cannot measure pressures directly using pressure measuring equipment, the best way to monitor it is by keeping an eye on velocity. Every handloader should own and use a chronograph.

Between 1 and 2 is your load, I agree with JG on this load your way over and a 85-90 degree day with humidity will ruin your day. I load a 140 vld right at 47 grains of RL 26 that shoots right around 3/4” at 500 yards. Its a good combo lapua srp with a cci small rifle mag primer.