Different battery setup in 3405 host.

I have a 3405 host running a rkcstr driver and am having to use the protected 10440 batteries and i have lost 2 of them going flat on me. One died after about 20min of use on the laser and then i charged the 2 good ones and an extra one i had that i charged and then i ran the host with a GGW for about 15 minutes and then i put my LCC diode running a rkcstr driver set at 400mA and then after a couple minutes i lost another 10440 battery. Well i just ordered 6 more of these batteries but was wondering if anyone else that is running this 3405 mxdl host with a rkcstr driver, have they been able to run any other size batteries in them and got good results. I just dont like these 10440 batteries and i dont have the money to get a different host and heatsink. I really like the 3405 with the heatsink i have now but just hate the 10440 batteries. Anyone have any tips on a different setup?

You can use 2xRCR123A in it with slight modification. IIRC, I took out the black plastic/brass piece in the end cap which I believe just has a spring under it. That allowed for more room. Then used cardboard from a toilet paper roll for insulation so the batteries would go in straight and wouldn't rattle.

Also, I'd recommend a flexdrive and Ni-MH AAA