Dirty optic glass constantly... How to plug the chamber witness hole?

[ar15barrels]

Would the optic's location, so close to the chamber, have any part in contributing to the problem?

Yes.
Make a simple little deflector from a piece of aluminum to deflect the gas.
The deflector can be held down by the RMR.

[PLINK]

FWIW I run a G17 with a Zev slide and Trijicon SRO for competition and training. With this set up the optic is closer to the ejection port. The glass does get dirty the more I shoot during a match or class but not enough to prevent me from seeing the dot. It can be annoying to look through dirty glass so I get that. I also shoot with both eyes open if that provides you with any helpful information. I have also taking a pistol optics class where we would put tape on the FRONT of the optic and engage targets with BOTH eyes open. What this shows is you can engage and still hit your target accurate enough even though the glass is completely occluded. I never really found a solution to preventing the dirt accumulation other than the occasional wipe with a lens cloth between stages or when I can. I do use a lens pen that has a compound in the cap that does seem to clean the glass well.

[hambam105]

shojivic,
Great question and great response all around.

If you reload please let us know the load particulars. And did you try using some elses reloads or factory loads?

Can you chronograph your loads? A weak primer spark causes all kinds of issues.

I think AR15 Barrels has the answer. He usually does on gun issues.

[shojivic]

FWIW I run a G17 with a Zev slide and Trijicon SRO for competition and training. With this set up the optic is closer to the ejection port. The glass does get dirty the more I shoot during a match or class but not enough to prevent me from seeing the dot. It can be annoying to look through dirty glass so I get that. I also shoot with both eyes open if that provides you with any helpful information. I have also taking a pistol optics class where we would put tape on the FRONT of the optic and engage targets with BOTH eyes open. What this shows is you can engage and still hit your target accurate enough even though the glass is completely occluded. I never really found a solution to preventing the dirt accumulation other than the occasional wipe with a lens cloth between stages or when I can. I do use a lens pen that has a compound in the cap that does seem to clean the glass well.

Well, Plink, I hear all that you said, and I experienced similar training points/lessons when I went thru my transition class. All valid arguments, and I suppose I've just reached the point where you guys have reminded me to accept the inherent drawbacks to optics!

I guess I've been to willing to blame the M&P barrel too much, thinking erroneously it was the culprit alone! Which is good.. this gun still runs like butter and out-shoots my capabilities.

Apparently my OCD was creeping up on me, and the rather dirty-shooting ball ammo I've been burning thru made the issue worse than I'd recalled seeing before.

[shojivic]

shojivic,
Great question and great response all around.

If you reload please let us know the load particulars. And did you try using some elses reloads or factory loads?

Can you chronograph your loads? A weak primer spark causes all kinds of issues.

I think AR15 Barrels has the answer. He usually does on gun issues.

Hams, I don't reload. Although I wish I had taken up that hobby long ago! I shoot mostly factory stuff, but the minimal reloaded stuff I picked up here from various Calgunners over the years has been stored mostly.

Therefore, I also never invested in a chronograph. Additionally, I am mainly an indoor shooter, as the local indoor range options for me have better hours and accessibility for a family guy trying to get in some practice at odd hours.

Again, I offer my thanks to all the insight provided. It all boils down to some of life's simplest lessons: Sometimes you have to take the bad with the good, and Nothing good (optics) comes easy (cleaning regimen).

[saudadeii]

<snip> And this buildup is equivalent, whether it be the 4" compact or the 3.6" SubCompact (now sold). The fact that it is a carbon based residue leads me to conclude it's from combustion: therefore, the witness hole is the only logical explanation.<snip>

[ATTACH]1154062[/ATTACH]

I must be missing something. The "residue" appears to be concentrated at the front of the hood not by the LCI.

I have 3 M&Ps, a Full, a Compact and a Shield (all 1.). My full has a 5" ported CORE slide kit and RMR. None of them exhibit that much residue after a range sessions. Now, admittedly, I've never shot more than 100 rounds through anyone of them in a single range sessions. However, the RMR remains clear. I always clean/lube after each range session.

[shojivic]

^^^
I agree with you on those two points. But I think you'd see more residue after shooting more than a hundred rounds.

The cheap ammo I'm trying to use up, plus the 200+ rounds I'm shooting at a time, was just becoming something I thought could have a solution.

It wasn't something that was an impediment to effective operation, rather just an issue that I thought could be somewhat remedied. Randall and the crew set me straight!

[therealnickb]

Just put a little piece of clear tape on the optic when you’re shooting the dirty stuff.

[saudadeii]

I wonder if that ceramic coating you can put on windshield might help.

[naz]

Not sure if it?s feasible for your slide but how about using a large optic like romeo3xl where the base of the optic will cover the hole

Or if there are any barrels available without that lci hole, switch to that

[hambam105]

OP,

One shooting session firing 200 rounds, indoors, probably from the same point within a hour or two, right? Most indoor
shooters probably shoot less than half that amount in the same time period.

Comparing your situation to Action shooters, they mainly shoot outdoors from different positions. So these shooters aren't
exposed to the level of smoke you're in so the particles do not have the time to settle on the optic screen.

Remember, more than likely AR15 Barrels found the main cause of your situation.

As for OCD, perhaps NON-OCD shooters are experiencing the same situation but just do not notice it.

[shojivic]

Just put a little piece of clear tape on the optic when you?re shooting the dirty stuff.

Actually, not a bad idea, but like OIF Vet said, just wipe and be done.

I wonder if that ceramic coating you can put on windshield might help.

Interesting thought, but aren't ceramic coatings more for protective/impact protection rather than just a barrier to dirt? I have zero experience in this stuff.

Not sure if it?s feasible for your slide but how about using a large optic like romeo3xl where the base of the optic will cover the hole

Or if there are any barrels available without that lci hole, switch to that

I'd definitely use a factory M&P barrel that eliminates the witness hole, if they made it, but no luck as far as I know. And like I said, I have to stick with factory. And I understand the idea of using a different optic that might cover the witness hole, but that also puts the optic very close to the ejection port and flying brass.. chipped optic glass?

OP,

One shooting session firing 200 rounds, indoors, probably from the same point within a hour or two, right? Most indoor
shooters probably shoot less than half that amount in the same time period.

Comparing your situation to Action shooters, they mainly shoot outdoors from different positions. So these shooters aren't
exposed to the level of smoke you're in so the particles do not have the time to settle on the optic screen.

Remember, more than likely AR15 Barrels found the main cause of your situation.

As for OCD, perhaps NON-OCD shooters are experiencing the same situation but just do not notice it.

Hambams, you're probably right in the indoor vs outdoor range argument and the concentration of dust within an enclosed area that contributes to the buildup.

At this point, I'll look for a disposable, pre-moistened wipe/packet product that would make it easier to clean between reloading, and would be more convenient than breaking out the spritzer solution bottle and microfiber towel... so tiresome.

[therealnickb]

Actually, not a bad idea, but like OIF Vet said, just wipe and be done.



Interesting thought, but aren't ceramic coatings more for protective/impact protection rather than just a barrier to dirt? I have zero experience in this stuff.



I'd definitely use a factory M&P barrel that eliminates the witness hole, if they made it, but no luck as far as I know. And like I said, I have to stick with factory. And I understand the idea of using a different optic that might cover the witness hole, but that also puts the optic very close to the ejection port and flying brass.. chipped optic glass?



Hambams, you're probably right in the indoor vs outdoor range argument and the concentration of dust within an enclosed area that contributes to the buildup.

At this point, I'll look for a disposable, pre-moistened wipe/packet product that would make it easier to clean between reloading, and would be more convenient than breaking out the spritzer solution bottle and microfiber towel... so tiresome.

And yet, you rejected OIFs answer and ?moved on?.

[shojivic]

^^^ Oh nickb,

If we only took the first response we ever got, we would be missing better results from the more constructive members, instead of just the guys who want to raise their post count. There WERE better responses and insight offered, but I weighed these and decided on the practical limitations of my restrictions. Vet didn't offer anything I didn't already know and practice. Get it? Don't be trite...

[therealnickb]

^^^ Oh nickb,

If we only took the first response we ever got, we would be missing better results from the more constructive members, instead of just the guys who want to raise their post count. There WERE better responses and insight offered, but I weighed these and decided on the practical limitations of my restrictions. Vet didn't offer anything I didn't already know and practice. Get it? Don't be trite...

Interesting. I took it as you not wanting to clean your lens. Hence, my simple disposal solution. Then you reversed course to only seek out the solution you previously dissed.

Be well and take care.