That's the loaded chamber indicator. All the M&P's either have that or a sort of lever/spring unit (similar to the XD/XDM pistols) that sticks up in the front to let you know you have a round in the chamber.
A lot of times when a pistol gets dirty real quick in that area it's low powered/low pressure ammo. The ammo you're using doesn't sound like low pressure ammo.
I've never had that issue (lens getting that dirty, that quick). Maybe another member on the forum here would be more help than me.
One suggestion might be to keep trying ammo in the hopes something will seal better around the case walls (pressure expands the case walls and seals them against the barrel/chamber walls to prevent/minimize gas blowing back towards you/the red dot. The ammo you're using should be pretty decent pressure wise.
You might also contact S&W Customer Service and tell them about the problem if no one here can help you with it.
They all get dirty (lens, lights, etc. from firing but yours seems to be happening faster. I usually use my t-shirt to wipe the lens off. Or the little lens cleaning cloth that comes in the Holosun box with the optic.
A lot of times when a pistol gets dirty real quick in that area it's low powered/low pressure ammo. The ammo you're using doesn't sound like low pressure ammo.
I've never had that issue (lens getting that dirty, that quick). Maybe another member on the forum here would be more help than me.
One suggestion might be to keep trying ammo in the hopes something will seal better around the case walls (pressure expands the case walls and seals them against the barrel/chamber walls to prevent/minimize gas blowing back towards you/the red dot. The ammo you're using should be pretty decent pressure wise.
You might also contact S&W Customer Service and tell them about the problem if no one here can help you with it.
They all get dirty (lens, lights, etc. from firing but yours seems to be happening faster. I usually use my t-shirt to wipe the lens off. Or the little lens cleaning cloth that comes in the Holosun box with the optic.
