Tapco gas piston in STG-58?

[Oklahoma Joe]

I was wondering if anyone uses or has used a TAPCO gas piston in a STG and if so do they function fine? Also what is the size of the piston head diameter? I know that the original STG piston is .4310. Thanks in advance!:)

[Pluribus]

Don't know the diameter but, yes, you can use the Tapco piston in a Stg and, yes, it will/should function just fine. I have several different Fal's with Tapco piston's, including one of my Stg's and, they run just fine.

[MAINER]

Gunthings carries Tapco gas pistons and certifies them for .430 heads.