Newbie here looking for expert advice. First of all I am in the dark for anything flashlight related. so here it is, a buddy gave me a SF 3P he no longer uses.I put in a fresh surefire CR123 but the light isn't exactly very bright. I would like to try that DX R2 (rated 3.6V) drop-in.So my question will it work with 3V ( one cr123)? If not what improvement do you suggest? Thanks in advance