4th Generation Glocks

Update: It appears as though I was incorrect about these pistols being the “4th Generation” of Glock pistols. Rather, they appear to be a somewhat modified third generation — the “Rough Texture Frame Pistol”. From what I hear, the actual 4th Gen pistols will have adjustable backstraps and a less-aggressive grip pattern than the really rough textured RTF ones shown below. My apologies for any confusion.
The crowds were slightly less at the Glock booth today, so I was able to get my hands on one of the 4th Generation “fish gill” Glock pistols and a few minutes of time from some of the Glock employees.
According to the reps, all the internals are the same. Existing replacement and aftermarket parts will fit 4th Generation pistols.
New Slide Serrations
When asked why Glock changed the rear serrations from the previous straight lines to the new, curved design, one employee answered unofficially, “it’s high-speed, low drag” (( In short, it’s new and shiny. People like new and shiny things. ))
Another employee mentioned that the previous serrations went all the way from the top of the slide to the bottom, and so the steel at the bottom of of each serration was thinner. He had personally seen two previous Glock pistols, each used by extremely heavy users (100,000+ rounds out of each), suffer failures at the base of the serrations where the slide bent outwards. The “fish gill” serrations stop a millimeter or two above the base of the slide, leaving the base of the slide thicker and thus stronger. This is obvious in the below photograph that shows both the old and new serrations:

Textured Grips
The 4th Generation pistols also sport a new texture on the grip:

This texture consists of numerous tiny polygonal (( According to the employee. )) nubs on the backstrap, sides, and finger grooves of the pistol, rather than the larger, blockier nubs found on the backstrap and finger grooves of previous generations of Glock pistols.
While previous generations had textured panels on the grips, the new texture is considerably more “aggressive” (( Quoting one of the reps. )) than the previous texture. I’m inclined to agree, but feel that the new texture is extremely uncomfortable — the grips feel extremely abrasive, and I find the gun uncomfortable to hold with a firm grip. I’m also concerned with the gun gripping clothing, making concealment more difficult. Abrasion of clothing is another concern voiced by some readers.
A member of Pennsylvania Firearm Owners Association (I’m terrible with names, so I apologize for forgetting!) was walking around with Louis and I, and mentioned to the employee his concern about the possibility of the new texture irritating the skin on one’s waist when carrying the gun in an IWB holster.
It’s possible to make things “grippy” without making them feel like sandpaper: Hogue aftermarket grips are extremely comfortable and grippy without being hard on one’s hands. I doubt Glock would be able to integrate both the ordinary plastic used in their frames with Hogue-type rubber panels in a single molded piece, but I feel that’d be a better option than the new texture.
According to one of the reps, the texture becomes less “aggressive” over time, while still retaining its gripping ability.
Glock had small survey cards where they asked people’s opinion of the new serrations and texture. I indicated that I preferred the previous textures as they were more comfortable, and the previous serrations (though I wouldn’t mind if they stopped the serrations above the base of the slide, so as to strengthen it) due to their more utilitarian appearance, ease of gripping, and ease of cleaning.
Magazines
I inquired about the notch on the front of magazines shipped with current, non-4th-Generation Glock pistols. My understanding that the notch was designed to allow for an ambidextrous magazine release was confirmed, though the pistols equipped with such a release (( The G20, 21, 29, and 30 “SF” models. ))? are not terribly popular in the US for a few reasons, most notably because many holsters fit the pistols in such a way that they depress the ambidextrous mag release.
This issue results in the magazine being released when the pistol is reholstered. According to the reps, this is a problem with the holster makers, not with Glock — the design of the pistols is such that it is not possible for Glock to include an ambidextrous magazine release that doesn’t get pushed by most current holsters. In order for them to do so, the holster manufacturers would need to slightly redesign their holsters.
Additionally, one of the new models has a standard 1913 Picatinny rail, but this fits poorly with existing holsters due to the width of the rail. The models with the proprietary “Glock Rail” do not suffer this problem as the rail is smaller, but such models are still uncommon due to the mag-dumping-when-holstered issue.
None of the models on display at the booth were the “SF” models equipped with the ambidextrous magazine release, though they were selling various items like hats, shirts, and R. Lee Ermey (( Who, among his numerous other achievements and positions, is a Glock spokesman. )) action figures. The Gunny himself was present for a few days for handshakes, autographs, and pictures, though the line to see him was quite long. In overhearing his conversations with people, he seems like a decent guy; Mr. Ermey, if you happen to be reading this post and are in the Tucson area, please allow me to treat you to a drink.