I got an answer from the developer over on the 68forum.
Quote
60,000PSI max using QL. But the person running QL must know how to set it up. Most people in the AR world think cartridges are loaded to 2.26 while everyone here knows PRI mags allow loading to 2.295 or 2.3" The other thing is QL does not work so well with the 6.8 bore especially with 5R rifling. The engraving force is lower and the bore area is larger. Comparing the 11 twist 4 groove barrels we sold to the 5R barrels we sell the 5R barrels usually run 60-80fps faster, some 90-100fps faster.
If the barrels are running faster with the same loads, it's because they are generating more pressure.
For a guy who trumpets the physics of killing power, you sure seem to ignore the physics of pressure.
