Selecting and installing Glock sights in the HTA MULTI Base

If you've checked out our MULTI Bases, you probably understand why we wanted to make them in the first place. There are so many guns out there that, for one design reason or another, simply don't lend themselves well to traditional fixed or folding back up iron sight systems. Something compact, lightweight, and rugged was needed to put BUIS in places others couldn't go. Pistol sights seemed to fit the bill, taking up as little space as possible, being rugged and easy to acquire, lightweight, and just as importantly, incredibly diverse in their design and application. Glock sights, in particular, have seemingly endless options. While this allows our MULTI Bases to be tailored for specific applications, the overwhelming number of styles and sizes can cause some confusion in deciding what sights to use and ultimately, how to use them. This guide will help you select and install a sight set to best suit your needs.

Deciding on the sight style is going to come down to what you need and expect out of the sights. You'll want to set the parameters for range, adjustability, and acquisition based on your intended use. As a general rule, these bases/sights are designed to work best for closer range sighting situations between 0 and 100 yards and with as long an eye relief as possible. Pistol sights have their limitations and are not inherently the best option for longer range/precision shooting. That said, these are meant to serve as a simple and effective backup on guns which otherwise couldn't have iron sights. If your life depends on it (or just your day at the range), these will provide you with a rough point of aim that gets you much closer than firing blindly through a dead red dot lens or at a doorway in the dark of night. 

Acquisition and Sight Style

Starting with sight acquisition, there are a few key areas to examine; notably, whether you want night sights and/or if you want those sights to co-witness in your optic. There are a ton of great choices from lots of manufactures for night sights and for sights with fiber optics in them as well. If you plan on using these on a home defense gun or in low light conditions, 3 dot night sights are a  superb option. Several ghost ring sights are also available for Glocks and can provide excellent field of view.

The matter of co-witnessing (being able to see the sight picture of the backup sights through the lens of the primary optic) can be a bit trickier and will depend on your optic's lens height. Ameriglo, for instance, makes several options in their 7XL - 9XL size range that work well with "micro" red dots like the Burris Fastfire, Trijicon RMR, and Vortex Venom, but these are not currently available with tritium lamps. Some red dots sit lower still, like the Vortex Sparc, and the AimPoint H2/T2 series. These red dots can cowitness with more common suppressor height night sights. Measuring the height of your sight window to the rail will provide the height you'd need to clear the lens of your red dot. Our bases sit approximately .150" above the rail but you'll also want enough extra height to ensure you can get a clear view of the sights.

If you can't get the right height combo for the setup you have or don't want any distractions in your field of view, another option is to add a QD riser or mount to your optic, so if it goes down, it can come off and the MULTI Base will be ready and waiting. Bear in mind, that to get a good sight picture, you'll want at least 1" of clearance between the cheek rest (if any) and the top of whatever sights you select. If they are too short or there isn't enough rise to the rail, getting your head low enough to see them can be difficult or impossible with a stock in the way. Thus, these sights aren't great for flat top firearms with stocks unless you plan on using some type of secondary riser. Flat top pistols like Stribogs, AR9s, CAA/MCK kits, etc. however, can work with these bases without a riser if you plan on shooting them like a traditional pistol.

Range and Setting a Zero

Adjustable pistol sights are ideal for dialing in a zero, especially if you need it to be fairly precise, but most pistol sights will be fixed which means you'll want to get the relative height of the front and rear sights correct before you install them. Determining a zero range and selecting fixed sights based on that is perhaps the most challenging step in this process, but with some simple math, you should be able to get fairly close. All you need is to plug your specific values into a formula to get a rough estimate of the sight height differential between the front and rear sights. Here is the estimation formula: 

When calculated out, this formula should give you a small decimal fraction of an inch- usually somewhere around .005-.040", depending on your desired range and rail height.  This is purely a relative measurement gauging the height difference between front and rear above the top of the bases. If you arrive at a calculation of .025" for a desired 25 yard zero, you need to buy a sight set that has a front sight .025" shorter than the rear sight blade. It's important to note that different manufacturers of sights may have different methods of measuring the height of the front and rear sights but the dimension this equation output refers to will be the difference in the height above the barrel between the front and rear sights and does not take the dovetail into account.

Let's do a quick example. Let's say we are using a PS90 and want a zero range of 50 yards. The typical 5.7x28 FN 40 grain load drops approximately 1" at 50 yards when fired perfectly horizontally. The height over the bore of the sight rail is roughly 3". Our desired zero range is 50 yards, or 1800 inches (50yd x 12ft x 3in = 1800"). Sight radius is roughly 6 inches. Plugging the values into the equation, we get:

((1" bullet drop + 3" sight height) / 1800" range) x 6" sight radius = .013" taller rear sight than front sight

Another way to think about it is this: if the rear sight sits .013" higher than the front sight when installed and the sights are 6" apart, then for every 6" of line of sight, the sights will be aiming downward .013". At 50 yards, that point of aim is now 4" below a perfectly horizontal line of sight. When you consider the sight rail was already 3" higher than the bore and account for bullet drop of 1", theoretically, 50 yards should be fairly close to zero.

Theoretically is the key word. That's because this formula assumes that the sight rail and barrel are perfectly parallel and horizontal. Variations in barrel/rail angles as well as ammunition differences and other factors can throw off the results. This formula will provide a basic guide to selecting the correct size sights but your zero may not be exactly at the calculated range due to these confounding variables. Once assembled, you will be able to find the exact zero range and then learn proper hold over technique for various ranges, although most pistol sight sets should fall consistently within practical levels of self defense accuracy. If one of your requirements is to have a set zero range, or you're doubtful you can get an accurate estimate based on your formula inputs, adjustable sights might be a better option to ensure you can achieve the desired outcome.

Windage, on the other hand, is simple to adjust for and works just like it would on standard pistols.  If shots are impacting left, the rear sight needs to be pushed to the right and vice versa. The same formula listed for zero range above works for windage, except the "over the bore height" can be ignored and "bullet drop" can be exchanged for horizontal drift. The rear base is marked with windage gauges at every .050" to help track movement. Marking the rear sight's centerline with a pencil can provide a helpful and temporary index point as you make adjustments.

For both installation and adjustment, we recommend using a sight pusher tool and our 3D MULTI Base installation jig. A rail riser or similar section of picatinny rail can also serve as a jig to hold the bases in a sight pusher. It may take some guessing and checking to adjust windage, since the sight base will need to be removed from the firearm to be adjusted, but once set, pistol sights should hold zero extremely well even on the most powerfully recoiling guns. A 5/64" hex key is included for mounting hardware, but a Glock sight tool, and a medium strength thread locker for the front sight/attachment bolts are recommended for proper installation. If you have any questions on any of this process, always feel free to reach out and we would be happy to assist. 

Thank you for taking a look!



Date 1/25/2023

Nate neeley

Date 3/5/2023

High Tower Armory, LLC

Date 6/12/2023 9:56:56 AM

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