ordinary bulb for magmod

I did build a Mag85, but I had a couple of other mags laying around not doing anything so for an easy project to put more interest into one of them I loaded it with 7 alkaline AA's and a RadioShack KPR112 (6V) bulb. I got worried about overdriving the bulb so much so I swapped it for a KPR118 (7.2V) bulb. This bulb was still bright and not yellow, but didn't last through the first set of batteries. After something like 30 min. runtime, the set of 7 batteries + adapter measure 9.9V. (FWIW I'm running the stock smooth reflector but I added a flashlightlens.com acrylite lens to smooth the beam a little.)

So my question is... is the KPR118 the best bulb for this, and how would mag bulbs work? Do they make a 5D bulb? Or I could go with a 6D bulb and add another AA to my stack. I'm trying to decide how much to overdrive these mundane type bulbs for a tradeoff between lifespan and brightness.

I carry this light in my car for use at construction sites. I also carry my Pelican M6 LED so it isn't a big problem if the bulb blows in the mag.

So, you mean the KPR118 didn't even last for half an hour on 7 alkalines?

I've run the KPR112 on 3 CR123 cells and the KPR118 on 4 CR123 cells and tend to get 'about' 2 hours per bulb though some seem to last quite a bit longer.

I've also used the 6 cell Xenon bulb on the 3 CR123 cells but that's not really overdriving it... it just gives you the power of a 6D Mag in the size of a 2C Mag.

They do make a 5D bulb, but I've never used one. I would guess that the 5D Xenon bulb won't last long on 7 cells but the krypton bulb will probably be fine.

The light was not dropped or anything like that, but it could have bumped something while being turned on. The person using it said "it just went out" and handed it back to me. Later I checked the and found that the bulb was burned out.

Oh... I've never run alkalines at all or NiMHs for very long on any of the KPR or XPR bulbs so I have no idea.