M&P 2.0 CORE and Red Dot Fogging

[SteelCityShooter]

I have a new M&P9 2.0 CORE with a Leupold Deltapoint Pro installed and the lens of the DPP gets sooted up after about 100 rounds.  I assume the soot is coming from the little loaded chamber witness hole at the rear of the ejection port.  The DPP is rather long and the lens is very close to that hole as installed.   

 

Anyone else with a CORE have this problem and any suggestions to avoid it? Any way to cover that witness hole and would it matter?  Does it happen with other red dots?

 

I have an older M&P9 2.0, not a CORE model, and the DPP never got dirty when installed on it but it was mounted on an adapter plate that replaced the rear sight and was further behind the ejection port.

 

 

[Rez805]

Yes, my lens gets a bit sooty after a while. I tend to wipe it down during make ready if it really bothers me.

 

Aside from that, it appears that a Sig Romeo 3 Max covers the majority of the hole with little to no impact on ejection. Someone posted a great set of pictures recently in this subforum

 

As for a permanent fix? Perhaps dropping a bit of weld on the hole and filing it to make sure it clears the slide. Edit: I'm not sure if filling the hole will affect functionality, but it doesn't strike me as a hazard.

 

Edited July 28, 2020 by Rez805