Tejano,
I made it home this afternoon and went to work on the H2O capacity of some fired 6.5x68 cases.
I took 5 once-fired cases and average the data once finished.
For the 5 cases I got an average of 82.36 gr total H2O capacity with an average of usable H2O capacity of 72.76 gr.
Ran these numbers in QL with a COAL of 3.337" and a trim to length of 2.650" with a 25" barrel, 62,000 psi with a max fill capacity of 110%.
Comparing the data generated with the above data with the data listed on the Barnes website for the 127 gr LRX and 264 Win Mag ........
Retumbo
6.5x68 264 Win Mag
71.5 max 62.7 max
3288 fps 3126 fps
IMR 7828SSC
6.5x68 264 Win Mag
64.0 max 56.0 max
3243 fps 2974 fps
RL-22
6.5x68 264 Win Mag
63.8 max 58.3 max
3222 fps 3067 fps
Magnum
6.5x68 264 Win Mag
68.7 max 67.1 max
3198 fps 3140 fps
So, based off of these data, the 6.5x68 beats the 264 Win Mag from roughly 60 to 270 fps depending upon the powder being used.
And, I agree with Azar based upon the data coming from QL, IMR 7977 may not be the best powder for this cartridge, yet I'm still curious why it is so far off from H1000 based upon what Hodgdon statement of it being close to H1000 powder.
