SF M3 with oval beamshape

I recently got me a new Surefire M3.
Fine light and so....

But there is one thing that bothers me, the beamshape.

It´s not round like the rest of my SF, instead it has an oval shape, almost flat.

Is there anyone else who have discovered this??

I have tried and switch between the MN10 and MN11, but it still looks the same to me.

The oval beam has got to do with the placement of the tungsten filament in the bulb. Unfortunately not much could be done about it. My MN10 does produce an oval shape beam but my MN11 is perfectly rounded.

SureFire use bar-like filaments for the MN10 and to a slightly less extent MN11 lamps. Combine these with the most efficient reflector/bulb combination SureFire (or any company) have designed results in a beam being generated that uses as much if the light from the filament as possible to form the central main beam.
This means the central main beam will be 'bar-like' or 'oval' as well, and the beam from the MN11 to a slightly lesser extent.

If the filament is a bar rather than a dot, the beam should be oval rather than round else light is being wasted.

Al

So because of the smaller reflector in the M3 it si not able to "shape" the beam enough to become round....?

The "bar" like shape would have become visible even from the MN20 or MN21 if I had been able to put them in the M3..?

My friend have a M3, the beam shape on that is also very oval. I understand why its like that, but I agree that it is annoying. If you shine the light in a narrow alley, you get a better view if you rotate the light so you get the oval beam vertically

Hehehe, yep I tried that too

Well, I just have to stick to my M3T instead..

But thanks for the info guys :twothumbs

Team Member said:

So because of the smaller reflector in the M3 it si not able to "shape" the beam enough to become round....?

The "bar" like shape would have become visible even from the MN20 or MN21 if I had been able to put them in the M3..?

Click to expand...

When you look at how close the reflector is to the bulb (how much gap there isn't) - this helps gather as much like as possible into the beam.
For a bar filament to produce a round beam the reflector would have to be inefficient, or have an overly disruptive surface finish, or be specially shaped so that the bulb (filament) can only be focused when it is alined in a specific orientation.

SureFire's TurboHead beams are also ovals - the standard lamps MN15/MN20/MN60 etc tend to have longer, thinner filaments compared to the High Output Lamp Assemblies (HOLAs) which tend to have shorter, thicker, fatter filaments. The HOLA beams tend to be less oval as a result.

Team Member said:

I recently got me a new Surefire M3.
Fine light and so....

But there is one thing that bothers me, the beamshape.

It´s not round like the rest of my SF, instead it has an oval shape, almost flat.

Is there anyone else who have discovered this??

I have tried and switch between the MN10 and MN11, but it still looks the same to me.

Click to expand...

Fix it with a Lumens Factory lamp assembly.

Outdoors Fanatic said:

Fix it with a Lumens Factory lamp assembly.

Click to expand...

how does that work? does LF LAs have a shorter filament bar than the stock SF LA?

:huh:

The oval beam if used horizontally does make for a nice field of view, especially in the woods. Vertically, it is good for identifying perps and targets. I align the oval part of the beam with the flat part of the body so I always know how the beam will be oriented when I turn it on.

For me the beam is only a concern when white-wall hunting. In actual use it doesn't bother me. I do notice slight differences between different lamps (older vs. newer, LOLA vs. HOLA).