I’m kinda thinking legalizing stop and frisk would be great gun control law. It worked for Rudy in NYC before the libtards and ACLU cried and called it foul. I’d rather give up my stop and frisk rights in order to catch felons with illegal guns than the left try to take my legally protected ones.

As a law enforcement officer I'm only comfortable with stop and frisk as it pertains to Terry vs. Ohio.

The Constitutional threshold of reasonable suspicion that a detainee was armed was established via the Supreme Court in Terry v. Ohio. It cannot be legislated differently, or thus that law would be "Unconstitutional". But, as any good officer can tell you, a good officer can usually get consent for a pat down. "Sir, for your safety and mine, would it be okay if I patted you down to make sure that you don't have any hand grenades, rocket launchers or anything that might harm us?"

So basically the "terry frisk" is already legal and gives the officer a way to legally stop and frisk someone.

I'm not LEO, but the way I read it, yes..."with probable cause"

A Terry frisk is legal but does not require probable cause but reasonable suspicion.

What is the difference between probable cause and reasonable suspicion?

Here is a fairly good definition:

Reasonable suspicion is seen as more than a guess or hunch but less than probable cause. Probable cause is the logical belief, supported by facts and circumstances, that a crime has been, is being, or will be committed.

Probable cause is the standard to make an arrest.

Suppose during the Terry Frisk, the officer finds a concealed weapon, which we will assume that to be illegal in the jurisdiction. The reasonable suspicion has just become probable cause and an arrest is made.

Yes, if they have reasonable suspicion that a crime has, is, or has been committed, that the person being stop is involved, and they have a reasonable belief that the person being detained is armed. It is actually easier to get to than it sounds. Shots fired, lone vehicle in area, suspect acting in a manner inconsistent with that of an "innocent person" (ie. evasive during questioning, furtive movements when pulled over, etc)