Does anyone know who makes a reliable aftermarket Glock slide for a G19.5. I'm hoping to add an optic to a my standard G19 5th Gen. I see a few out there, but don't know which ones are reliable. This would be for a carry weapon, including being a backup to my uniformed duty carry weapon (G19.5 MOS).

For less than the cost of a slide, you can have the factory slide milled to fit your optic precisely, at Primary Machine. With the slide cut exactly to the optic, it's not just screws holding it in place, and it will always go back exactly as it came off. About a hundred fifty bucks.

I have a Suarez slide for my G34, it functions 100% and the rmr cut is well done. If you can catch them on sale they are pretty good.

I had a brownells G19 slide and the rmr cut was tight to the point where it pinched my rmr and I had trouble getting it to run. While they were willing to talk on the phone they looked more at troubleshooting the rmr. I had no issues with it before or after running it on that slide, when I swapped it to other slides. Hopefully, they have improved.

Take a look at Shadow Systems, especially for use with an optic