6000/7=850 lumen/led. considering reflector and lens losses, every led needs to do 1000 lumens to get to 6000 total. That is 3A/led, 21A total, so 5.25A/battery. If you put a lot of work in this light (change the driver, improve the heat path a lot, lower the resistance of all springs), you could get that kind of current and get 6000 lumens, but no way that the light will do that straight from the supplier.
Probably not, from what I’ve seen most of these multiple led SRK’s come in far under the listed lumens. If somehow it did have a driver that did 15A+ total current it would get extremely hot, extremely fast and I don’t believe I’ve read of any SRK clone to do that stock.
It's Chinese lumens - totally false. I'd say lucky to get 3,000 lumens stock. Think the J18's (7X) stock did 3,000 - 3,500 and thought the 7x SRK style lights didn't do as well, though this one does have XM-L2's which is better than the typical XML T6 lights.