I just received my Glock 34 back from a professional gunsmith who did a lot of work on it. I bought the milled slide from OST, the RMR is a Trijicon RMR and the sights are Trijicon suppressor height night sights. The barrel is a threaded barrel.

I'll list what was done to it:

(1) Polish, hone and tune the Zevtech trigger system to amazing crisp break and reset (amazing trigger now).
(2) Cerakote slide after milling front serrations (Armorer Black color).
(3) Customized grip to my hands, built up backstrap, etc.
(4) Trigger guard work.
(5) Added the "gritty" material on it, a permanent application, feels absolutely fantastic.
(6) Large beavertail addition, allows for very positive purchase from the holster.
(7) New external slide release.
(8) Zev magwell was added to the grip (I had purchased it previously), with weight in the grip.

The thing is amazing now, and fits my shooting hand and support hand like a glove.

The guy who did the work is Bob Greer of:
Precision Custom Service
Hillsboro, Missouri
Phone: (314) 565-8458

It was well worth the wait.

Here are pics: