I would be interested as to how the Eagletac T10C2 achieves the claimed 296 lumens at the LED.
The Cree Q5 documentation says that the Q5 bin puts out 107-114 lumens at 350 mA. Max forward current rating is 1000 mA (at least in the older docs that go up to Q5 bin; the docs with the R2 bin seem to say 700 mA). At that current, the relative luminous flux is about 220%, or 235-250 lumens.
R2 bin is rated 114-122 lumens at 350 mA, or 250-268 lumens at 1000 mA.
Overdriven Cree Q5? Or has Cree improved the Q5 but not updated its PDF documents on its web site?
If overdriven, besides potentially impacting LED operating life, there is also the issue of maximum ambient operating temperature. The ambient temperature and maximum forward current are related and if you increase one, you decrease the other.