Mounting collimators on pistols is a trend that has been increasing for several years now and will not go away quickly. What's more, some experts of the other side of the Atlantic claim that it intensifies and there is nothing else but to accept the fact that shooting (or rather aiming) with a sidearm come down not only to aliginig the sights but, more and more often, also "searching" for a red dot .
Firearms manufacturers are slowly following the trends and are starting to offer the so-called optics ready weapons i.e. factory-adapted (by means of an appropriate cutout in the slide) for mounting Mini Red Dot Sights (MRDS), i.e. micro collimators. Glock "took up the glove" by releasing the MOS models of its Gen4 and Gen5 pistols. The Gen3 users had two options for mounting MRDSs on their weapons: using a special mount - a plate in the place of the rear sight, so-called dove tail mount, or milling the slide for a dedicated collimator at a gunsmith.
The Brownells company offers users of the Glocks 17, 19 and 34 slide that are factory-adapted for mounting the Aimpoint ACRO collimator.
The place for the collimator is milled in the slide, which eliminates the need for mounts and adapters. The undercut was made as low as possible to ensure a low aiming line. The advantage of the ACRO collimator is the closed emitter - unlike most popular micro collimators such as the Trijicon RMR, Leupold DeltaPoint, Docter/Noblex, Vortex Viper etc.
The design guarantees that stones, debris, etc. will not fall into the "center" of the collimator. Naturally, you still need to remember to keep the collimator's glass clean. The downside of the ACRO design is its greater weight and quite large size compared to the above-mentioned competitors. Slides for other MRDS models are also available.
The MSRP of slides with adapted for the Aimpoint ACRO is 229.99 USD (for the G19 and G17) and 269.99 USD (for the G34).
Sources: thefirearmblog.com,warriorpoetsociety.us,dueckdefense.com,atxarmory.com