The very best solution is to get an LED drop in. The Nitrolon really doesn't conduct the heat away from the module like aluminum bodied flashlights do. In the Nitrolon body of the G3 you need to find an LED drop in that is heatsinked well or that reduces it's output to manage the heat. This is actually not a problem because several nice units are available.
The Malkoff Devices
M60L is rated at 140 lumens for 6 hours max output on 3 123's and the
M60LL is rated at 80 lumens max output for
13 hours on 3 123's. Both have a good combo of flood and throw. If you like more flood he has the
M60LF model (designated with the "F"). To complicate things further, you can also opt for "warm" versions also which give the beam a more incandescent quality.
The
Surefire P60L is not heatsinked per se but it regulates its output to manage the heat. It is rated at 80 lumens and runtime tests show it will run for around almost
6 hours on 3 123's. The Surefire dropin is a lighter weight unit with a very nice smooth beam quality and fits in an
SC1 spares battery carrier.
I think the very best solution for your G3 and maintaining the 100+ lumens you want would be the Malkoff M60L or M60LF.
The M60L or M60LF will run on one set of batteries (3 123's) for 6 hours. You would go through six sets of batteries (18 123's) with your stock P90 incandescent bulb to get that same 6 hours of runtime. 10 battery changes with your current stock P90 incandescent bulb would cost nearly the same as buying the Malkoff unit. If you like the G3 an plan to use it quite regularly then the LED upgrade will be very cost effective. Rudimentary breakeven analysis is around 30 Surefire 123's @ $1.75 each. If you are using it for hours on end every night then you will want to look into rechargeable options such as two 17500 li-on's and a charger.
