gdnagle
US Veteran
The PTS will be marked PTS on them if by chance you got the Chinese knockoff's that's where your problem is.
I've got an angled foregrip PTS, and it works fine. But I wouldn't use PTS sights.
What MajorLK says. I can't purchase anything Magpul (well a couple of things) from the USA and local dealers have hardly any stock and charge the earth. But I can buy PTS, and have used them on Airsoft guns for years.