Recently I picked up a new Glock 22. I already had about a dozen various Glocks to include a 22 and 35. I grabbed this new variant to see if Glock had finally taken some market cues and improved their product. I have only fired a small amount of rounds at this time but subjectively, it shoots softer. I attribute this to the stiffer dual-spring recoil assembly. It was comfortable and accurate. The trigger was standard-issue Glock but I worked some magic to get it to about 3 pounds and smooth. Sights are Dawson PIs with a black rear and fiber optic front.
There are a few small changes to the pistol that don't warrant complete detail. The frame rails are slightly changed and the trigger bar has a rounded protrusion, presumably to help lift the firing pin block more easily. The other changes are more functionally apparent and will be covered a little more in-depth. Of note, the slides are not interchangeable between the Gen 3 and 4 pistols.
1. The grip and mag release. The grip is not a sharp as the RTF frame. It will not tear up clothing and can be carried concealed. It seems to be more durable as well where the RTF grip pattern would lose some of it's bite after use. The mag release is flush to the frame and extends back towards the rear. It is about 4x the size in surface area and much easier to depress than even an extended Gen 1-3 release. I think people may find this the best upgrade of the package. It is reversible for wrong-handed shooters as well.
2. The guide rod. The guide rod uses a telescoping dual spring design similar to the subcompact Glocks. It requires a larger hols in the front of the slide and a new cut on the locking block for the larger rear flange. It is noticeably stiffer and shoots softer as well. I presume this to be Glock's answer to reports of stoppages with the lights mounted. I can't say, as I never had this happen with my .40 Gen 3 guns.
3. The grips are small. Equate the pistol with no backstrap to the "SF" version of the G21. It is shorter from front to rear. To customize the fit, a backstrap clips over the rear and is retained by a longer trigger group pin. The medium piece is roughly the same size as the Gen 3 Glock frame, and the large is roughly the size of the G21SF, although more narrow from side to side. It's a good system, and I think people will like it. I also believe most folks will just use the smallest size and leave the backstraps off.
This shot shows the smaller rear cavity of the Gen 4 gun, and the relative thickness of the two additional backstraps.
4. The magazines are nearly the same, and previous Glock mags fit with one caveat. There are cuts for the ambi safety as well as the reversible safety from the Gen 4 guns present on the Gen 4 mags. This is required for the safety when on the right side for lefty shooters. I presume these guns come with 3 mags to make sure the possible left handed shooter has a duty loadout. For righties, use whatever G22 mags you have. The rear of the feed lips is slightly different but does not appear to affect function. See below.
* FDE mag is Gen 3, Black is Gen 4