Just received a Surefire 6P Classic from a member of the web site. I am working on a BHD RO727, and wish to be accurate as possible. However, I read on another post in here someplace the 6P Classic bulb will not hold up to recoil stresses and should be replaced with an LED bulb. I also want to get closer to an original style of tape switch. Any assistance is welcomed.

I am assuming you are talking about some form of replica M4. Don't know what the correct bulb for that would be, but I have several 6Ps on my carbines that have been updated with a 325 lumen Malkoff LED head. To me, that makes it the perfect "all-around" light. I really like the 6P, but I need more output and durability than the supplied incandescent bulb can supply. My advice would be to update it with a Malkoff. If you are building some kind of replica, who will know besides you?

As far as Tape Switches, I couldn't tell you. I don't use them, because they seem like they would snag on brush if you are outdoors.

^^^ THIS ^^^

Malkoff M61 LED replacement bulb is a must for every 6P/Z.  I run a M61 in a 6Z and a M91B in both 9Ps.  I won my SF 6Z in '97 and carried it, but it's been on my UPR (Urban Patrol Rifle ) since '02.  Awesome little light.  I have an older Scout Light but I like my stout "retro" weapon light.  I was "issued" my tape switch and never thought about getting a spare.  

Look at SureFire's XM07.  It's not cheap.  I can't tell if it's for E series lights or 1" dia. tubes.

The Malkoff P61 will be the best LED upgrade. If you wanted a SureFire LED you could drop in a 6P LED which is rated at 85 lumens but looks more like 120. As mentioned the SR07 switch/pressure pad will screw onto the P6