The research Ive looked at is confusing. Ive shot gen 3 sf models primarily the 30sf, it fits like a glove. I thought I read somewhere that all the new gen 4 models are all supposed to be sf frames/recievers until you add the back strap on it to make it larger. Is this true? I am particularly interested in the glock 30, 20 and 21 which are all chunkier guns and would only work for in the "SF" size frame. Any clarifications would be appreciated. Glock dealers any idea?

Your statement is true.  G4 models are SF size w/out the backstrap.

thanks for fast reply.

Id say its true.. My gen 4 G21 without added backstraps feels just like my gen 3 G21sf

Id say its true.. My gen 4 G21 without added backstraps feels just like my gen 3 G21sf

 

Thanks how do you like that 21?

Thanks how do you like that 21?

Its a great gun. Shot over 1000+ rounds without any malfunctions. Have shot everything from reloads to +P with no issues. I highly recomend it