Surefire M972SUO6 Beam pattern change..

[Monty0124]

Hey all,

Been lurking for quite awhile and figure its time for post number 1.

I have a sure M972SU06 (turbohead) mounted on my AR-15 for work. When I first purchased the light it produced a nicely focused round beam. Lately the beam pattern has become distinctly oval. The light has never been damaged or dropped. Any ideas what would cause the change in the beam shape?

Thanks,
Monty

 

[Prolepsis]

Welcome to CPF!

My M3 Turbohead has a round beam (same bulbs as your WeaponLight).

Note that the KT4s (Turbohead) coupled with MN60 and MN61 lamp assemblies (the ones that go in M4 lights) *will* produce an oval-shaped beam from the get go.

I know that doesn't help you exactly, since I don't know why the beam shape would change for your light. Did you change the lamp assembly?

One of the resident SureFire experts will hopefully chime in. /ubbthreads/images/graemlins/smile.gif

 

[Monty0124]

Hey Prolepsis, thanks for the reply. I didn't change a thing on the light, other than batteries. It used to throw a really sweet round beam and now it's gone quite oval.

the only thing I can think of, and who knows if it's even relevent, is that the light has discharged 2 full sets of batteries accidentally. I carry my rifle in a soft bag and it shifted in my patrol car putting pressure on the tape switch and activating the light, running all the way down. Do you think there could be some kind of damage to the reflector from heat? The reflector does not appear distorted at all.

I'm in the process of changing over to a Z48 clickie tailcap so this doesn't happen again.

 

[supes]

That sounds weird. Have you tried another lamp in it?

 

[Monty0124]

[ QUOTE ]
supes said:
That sounds weird. Have you tried another lamp in it?

[/ QUOTE ]

Nope, not yet. Don't have another to try. I'll put it on the top of the list of trouble shooting tactics.

Guess I need to come up with another MN15 assembly....thanks, good thinkin.

Monty

 

[Size15's]

It is unlikely that the accidental discharges have anything to do with the change in beam shape. However, I suggest you look at getting the XM06 TailCap. The XM TailCap allows you to "LockOut" the switches and you can also unplug the cable from the TailCap.

The MN15 and MN16 beams are usually oval with the MN15 beam being more oval (or "squashed").
See some of Shelby Chan's Beamshots here

If you unscrewed the TurboHead bezel you may have rotated the lamp assembly round in its 'socket'. This shouldn't change the beam unless there is some dirt between the socket and lamp assembly. It may be worth trying though.

Another possibility is that the filament has been deformed. This can happen - Shelby's photos show what they should look like.

Please let us know what happens/what you decide.

 

[Monty0124]

Size 15's, good to see you here bro and thanks for the reply.

Ok, here is what happened with my light. I was using the 125lumen MN15 assembly. It is the MN15 causing the problem. If you go to the beam shot page listed by Size 15's you'll see good close up shots of each bulb assembly. My MN15 developed noticeable dark spots on the glass next to the top of each vertical pole that holds the filament. The beam pattern I was getting was about half the size of the MN15 pattern shown on that page. I switched out to my MN16 and the beam was back to normal.

Needless to say I got ahold of my surefire guy, who first recommended I check for the dark spots on the lamp, and have a new MN15 assembly enroute.

Thanks for the help everyone.
Monty

Edit: I've since switched to a vertical foregrip, offset mount and clickie tailcap so I don't get anymore accidental full discharges again.

 

[Size15's]

I'm glad you're being taken care of.

Al