gas piston diameter

[Z28-427]

What is the diameter of the gas piston suppose to be. Thank You. This is a great website

[Templator]

Most that I've encountered have been .428-.430". I have 2 that I bought from DSA that are .432"

I've found that an oversize gas piston will do wonders for a FAL with a balky cycling system. One of my FAL's won't function at ALL with a .430" piston but will cycle reliably on a setting of 5 with a .432.