I assume you mean "
M951" rather than "951". I just spent a few minutes trying to find out what a 951 was... 950 is a classic universal WeaponLight and use of the "1" at the end of a classic WeaponLight model number usually indicates the tape switch is intended for attaching to the pistol grip rather than forend handguards. That's not how the 950 series work and there isn't a model 951.
But, M951 makes more sense, although M95 is a better shorthand since the "1" only indicates the mount is dual thumbscrews rather than swan throw lever.
Anyway, if the question is asked:
"
Why don't any of the aftermarket LED dropins I've tried, function in my M95 WeaponLight?"
Could the shock isolated bezel be to blame here?
Perhaps the aftermarket LED dropins do not have strong [and or long] enough spring contacts?
If you have a 6P or G2 bezel try putting them on the WeaponLight and seeing if that makes a difference. You could also try putting the WeaponLight's bezel (aka "M2" bezel) on a 6P or G2 etc to see whether the aftermarket dropin works in that combination. If it does, perhaps the WeaponLight's TailCap switch spring contact is to 'blame' and it needs to be modified (stretched) to work with the aftermarket dropin.
Does your M95's Lamp Module adapter collar have a black plastic widget inside?
This is a LU60 Lamp Module adapter collar:
The black plastic widget is used to ensure correct contact of the SureFire Lamp Assembly during heavy and abusive use - SureFire started including this widget following feedback gathered from users of the M95 in theatre.
The widget may need to be removed in order for aftermarket dropins to function.
Al