The 30 is by far the best GLOCK I've owned, I love the thickness of it the most.
I had a 21RTF as well (sold now) for the same reason, they fit my hand perfectly, The 30 is pretty much my every day CC choice. I have other GLOCKs and have sold and bought GLOCKs but the 30 always stays it was actually my first GLOCK. I have done a few things to it and its the smoothest i've ever felt, it probably has 15k rnds through it plus "trigger work"

it is an origanal CKU gun so it is one of the first from july 1997. For me the longer back strap plug and "finger extensions" are a must and I have them on all my 30 mags, I also kept a few 21 mags over the years for range shooting I have +2 extenxions on 2 of my 21 mags making the gun capable of 18rnds

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this is hands down the most reliable weapon I have ever owned equal to the reliabilty of my Kalashnicov..... the only part that ever NEEDED replaced is the RSA, not becuase it lost it's integrity...but becuase peice of plastic that held it captive wore out and the spring would slip out over it but not while using the gun, so honestly the broken part could have stayed !
But this is to be expected of a plastic recoil rod.
My buddy's and I rolled this gun in snow, rain, and mud we did a few things from the GLOCK "torture test" and NEVER failed to feed or failed to fire.