Difference between G21 and G21SF?

[hybridatsun350]

Serious question- Are any other models going to come out in the SF like the 17?

Probably not with the creation of the Gen 4 models. Supposedly the smallest grip insert allows you to get the size of a SF model.

The SF's only come in the large-frame guns and the SF's are about the same size as a Glock 17 (they're a little wider). Not a whole lot can be done to the 17. There is a little room, but nothing Glock is going to put money/R&D into.