code 4 rechargeable flashlight questiion

I have a code 4 flashlight also that is very similar (I think it may be newer than the one pictured) that charges from the tailcap, when plugged in. This was given to me by my uncle who is a deputy. The only replacement bulbs I am able to find are for the maglite 4 cell and they are very dull. the bulb is dropped into the reflector and held by a hollow threaded cap that holds it in place. I have been able to find the maglite 6v bulbs, but they have two pins on the bottom, and I need a bulb that is rounded on the bottom (idiot proof). Not to say I am an idiot.....Could anyone help me with some other options to get the most out of this great flashlight, without spending its value to make it operable again? Thanks in advance for any help!!

What you are looking for is a PR based bulb. It is the standard bulb used by maglite and many flashlight manufacturers. I am curious what the battery voltage is. The reason the 4d bulb is looking dim is because you may be underdriving it. As in not giving it the required voltage for optimum output. If it is rechargeable. It will probably be something like 3.6v or 4.8v. In that case, go to radio shack. They have bulbs designed for those voltages. Check their website.

Take a reading of the battery fully charged. Knowing the voltage will go along way in recommending a bulb.

As postedPR based PR based bulb , no prongs,threads just a contact on the bottom and a flange next to glss part.

Marking / packaging can be very confusing. MagLite list their bulbs by number of cells and battery cell size , such as 2 AA , 3C , 2D.
A nonimal 2 cell bulb would be for 3 volts and a 3 cell would be for use with 4.5 volts however most regular flashlight bulbs for use with 2 cells (3 volts) are really marked 2.4 volts and 4 cell ones are marked 4.8 volts.

A common carbon zince AAA,AA,C or D battery is a nonimal 1.5volts.
Same size cells in Nicad or NiMH are nonimal 1.2volts .

I will check and see! thank you for your help, I do appreciate it!

it is a 6 volt rechargeable battery...I did not test it but that is what it says on the wrap. do I have to test it?