In response to the issue that I mentioned in Post #80, I decided to spend a bit of time trying to address the problem tonight...
I went to my department's range this evening, and tried shooting quickly through a couple of our qualification courses. As expected, I once again experienced the unintentional slide-lock issue when I utilized the thumbs-forward method of gripping the weapon.
I then had our Glock armorer switch out my factory extended slide release for a standard Glock slide release/stop, to see if this solved the problem
(as I mentioned before, the Glock 37 comes with a factory installed "extended" slide release, which protrudes from the gun more than the "standard" Glock slide release). After making this relatively simple modification, I again shot through the qualification course using a thumbs-forward grip. This time I experienced no issues, and continued to have success even when I exaggerated my grip in such a way as to try to make the slide lock back while shooting. So, at least in my case, using the older style Glock slide lock solved the issue that I mentioned above!
Moving on, this issue naturally brought up the subject of grip styles with our range officers. As I mentioned previously, two of our range officers strongly prefer the thumbs-forward method, and both of these officers are very accomplished competitive shooters.
Strangely, a couple of our other range officers prefer the thumb-lock style of grip for combat shooting, and feel that the thumbs-forward method is best left to the competition shooters. As far as I know, neither of these other officers have competed much, but at least one of them has spent a good portion of his 35 year career as a SWAT operator, and has a wealth of knowledge to share with even our most experienced officers. His preference for a thumb-lock style of grip concerns the ability to retain the weapon during a struggle, and also addresses his concerns about running into the problems that I did (unintentional slide-lock, or unintentional slide-release).
So, I guess it comes down to who you ask! In watching some of the guys on my department shoot, I do see a mixture of the thumbs-forward and thumb-lock grips styles, though I think thumbs-forward has the edge. In USPSA competition I've noticed that nearly everyone at the local matches are using a thumbs-forward style of grip.
My opinion? Use the style you like best, and shoot it well