I have 5 P80s - four of them were bought as stripped receivers through an FFL (i.e. I did not make them)

Of the four, I've fully assembled two. The first one was a grey frame SN CA8XXX with a Brownells slide and barrel and it worked great. I had no issues, and decided to buy and assemble more.

The second was an FDE frame SN CA8XXX with a Brownells 19LS slide and threaded barrel. It had a hell of a binding issue; it was so bad I could rack the slide back half way and it would stay there. I couldn't figure it out, and thought it was the rear rails. I took a dremel to them and almost cut a bit too much off until I realized it was actually the front locking block rail causing the slide to angle too far down on to the rear rails - thus the binding. I tried using a stone at first to make sure the filing was even on both rails, but that was going way too slow and for an $89 frame mixed in with some frustration I decided to hack away with the dremel. Fortunately, I was able to salvage the gun and now it is actually one of my favorite pistols. I've got well over 1,000 rounds through it in just a few weeks with about half of those suppressed and it's been flawless.

I have two more black ones that I was assembling tonight. They are SN CA10XXX, and they are sequential. One made right after the other.

One cycles flawlessly and the other binds due to the front rail being angled a bit again. It's a bit disappointing to see such differences in QC. I could understand the differences in color may have had batch issues, but these are sequentially serial numbered. My intention was to throw RM06's on both of these and run them with Brownells slides and threaded barrels (standard 19 length) with one being used sort of as a "back up" to the first. However, I'm not really cool with dropping $1,000 and using a gun that I had to get to work with a dremel in either competitions or carry/nightstand duty. I have a few factory G19 frames and will probably build those up instead.

Anyone encountered this? Got any advice (aside from stick to factory Glock frames)? Am I risking anything by dremelling the rails? The first one I did cycles flawlessly, and while I'd count 1,000 rounds as evidence of reliability, there is no evidence of durability.

Note:
- Binding occurs with several slides. I have tried two factory Gen 2s, two factory Gen 3s, and two Brownell's slides (std and 19LS). It is absolutely a frame issue, and not an aftermarket slide issue.