Yikes! It looks like it's reflecting the inner barrel threading??
Did you take out the lens at any point? What kind of basic modding did you do?
Are you sure the lens seated proper when you put it back in and there are no burrs after cutting the barrel?
I cut down the side that the inner lens holder threads in. With this lens I think that is outward facing side, the side that the beam leaves from. I don't even see where the light could be hitting any threads...Which side of the lens housing did you cut down? I think the lens housing is too long too, but I haven't tried it in another housing, which I have. These are longer FL lenses than the aspheres we use for greater power output, so they needn't be as long as they are, but I wouldn't cut the lens down. You can buy brass lens housings on eBay for these and other types of lenses. I believe mine cost ~$1.00 each.
Sadly I would need it cut down. I will try and find some short housings on ebay but I havn't had any luck so far.Then, I would suggest you try a different housing at this point. It is really all you have left. That, or buy another G8 and don't cut that one down.
Sadly this isn't an option for me.If I want my adjuster to bottom out at say : ( a perfect infinity focus ) I simply push my module back into my host and tighten the set screw so that my adjuster bottoms out at the desired focus by adjusting the module depth, there is no need to cut down the lens barrel, I would rather add an additional set screw than contaminate a good lens, also you may have contaminated the lens surface/coating with natural finger oil or damaged the lens coating. It's best to avoid taking apart any laser lens as they work best when factory clean with their coatings intact. I always use compressed air or a hand puffer to blow away dust and avoid ever touching any laser lens.
It's a diffraction artefact caused by teensyweensy schumtz on the diode window and perhaps the lens. Maybe a very very tiny scratch.Sadly this isn't an option for me.