Jbailey,
My loads were chronographed with an oehler 35 chrono and the drops to 1,000 yds were spot on based on my elevation adjustments, so i am pretty sure my muzzle velocities are close. I published my muzzle velocites @ 2,928 fps, but that was 18' away from the muzzle, so my actual muzzle velocites are 2,936 fps.Sorry for posting wrong data!
The atmospheric conditions i was shooting in were as follows. Temperature 94*, Altitude 381', Barometric pressure 29.5, Humidiy @ 38.5 %. I had a 7 mph 180* wind (tailwind) that was consistent. Transonic flight is when the bullet slows below Mach 1.2, somewhere around 1,340 fps depending on several variables. Based on my calculations @ 1,200 yds my muzzle velocity was 1,382 fps, so i was close . I was showing sub sonic velocities @ around 1,440 yds.
I posted earlier, but it did not come up on the thread yet, So i will comment now on several variables that could have caused the bullets to open up or act erratic. My load has an es of 22 fps and an sd of 10. I was running the g7 b.c for the 139 scenar, because there is not an accurate g7 b.c out yet from lapua, as far as i know. Running the 139 scenar g7 BC and my muzzle velocity put me spot on @ 1,000 yds ?.We had a 54 yard variation between two leica range finders.The bullet was possibly entering transonic flight and lost stability.
What's puzzling me is the great results @ 1,000 yds, then @ 1,100 and 1,200 yds, things opened up. I would see the the splash of the bullets , hold off or correct,but no consistent hits or bullet splashes.
I have alot of things to work thru before i believe the bullets are not stable at those ranges. I had another load during load development that had better numbers , but the groups were not quite what i was looking for. I may tweak that load again to see if i get better groups and es !. This was the first time i have taken the 136 scenars to 1,000, 1,100, and 1,200 yds, so i have a lot more things to rule out, but i did like what i saw @ 1,000 yds.
If anyone has any insight or has taken these bullets out past 1,000 yds, please comment on your results.
Thanks!