Trijicon's 3x30 TA33: Best of the ACOGs?

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Currently, low-power variable magnification scopes are the rage on ARs and other general purpose utility type rifles. This makes a lot of sense as a 1-6x or 1-8x Low Power Variable Optic (LPVO) provides a nice blend of performance and flexibility. They can be dialed down to 1x for close work or dialed up for observing, target identification or taking a longer shot. The downside to LPVOs is their size and weight. A typical 21-ounce LPVO, and eight-ounce mount, add a noticeable amount of mass to a carbine. Many wonder if there is a magnified alternative to reduce bulk and weight, something compact like a red dot, but still offering some magnification. I believe a compact prism scope, like Trijicon’s 3x30 TA33 ACOG, can be a viable option to consider.  While I am intrigued with the latest marvels of optical engineering, I still find myself drawn to an old standard, Trijicon’s ACOG. A relatively old design by today’s optical standards, the 1980s vintage Advanced Combat Optical Gunsight (ACOG) still has a lot to offer. The ACOG is the work of the late Glyn A.J. Bindon (1937–2003). Especially noteworthy was his use of a Pechan prism assembly, similar to those utilized in roof prism binoculars. The use of a Pechan prism allowed him to drastically shorten the length of his scope without hurting its optical performance.

Rather than being a single model, Trijicon’s ACOG is actually an entire line of riflescopes broken up into distinct families. The genesis of their standard models was the TA01 4x32mm which was introduced in 1987. This model was selected for the US Army’s Advanced Combat Rifle program, which foreshadowed things to come. In 1992, the line was expanded with the addition of a 3.5x35mm model which incorporated dual fiber optic/Tritium illumination. In 1993, the compact line was created with the introduction of a 1.5x16mm, 1.5x24mm, 2x20mm and 3x24mm. In 1997, dual illumination was added to the 4x32mm series which was subsequently adopted by the US Army’s Special Forces. In 2001, a larger 5.5x50mm model was introduced. In 2007, Trijicon bridged the gap between their standard and compact models with the introduction of their 3x30mm TA33 model. This is the model of interest to us today. The TA33 is a fixed 3x prism scope with a 30mm objective lens. The prism assembly is housed in a tough body machined from forged 7075-T6 aircraft grade aluminum. To ensure the scope will remain waterproof, an aerospace pneumatic seal is utilized. To enhance optical performance the lens and prism air-to-glass surfaces are multi-coated. As the ACOG was intended for military use in the 1980s, the body is designed to mount directly onto an M16’s carrying handle. Through the use of an adapter, it can also be mounted onto a MIL STD 1913 rail.

The TA33 incorporates Trijicon’s Dual Illumination system. This consists of a fiber optic daylight collector which works in conjunction with a tritium lamp. The reticle is illuminated by the fiber optic during daylight and by tritium in lowlight. Due to the design, no batteries are required. This model is available with a variety of reticles. Options include a crosshair, chevron and horseshoe with bullet drop compensation marks allowing quick target engagement out to 600 yards. This model feature Trijicon’s Bindon Aiming Concept, or BAC. The BAC feature allows a shooter to quickly engage targets both at very close range, like a red dot sight, and at extended distances, like a conventional magnified optic. How is this possible? The ACOG is intended to be used with both eyes open, like a red dot sight. When tracking or swinging onto a target at close range your brain uses the non-magnified image from your non-dominant eye. This allows you to ‘see’ and track your target with the 1x of your MK I eyeball rather than with the magnification of the ACOG. At the same time you are tracking the target with your non-dominant eye, the brightly illuminated reticle jumps out to your dominant eye looking through the ACOG. Your brain automatically superimposes the brightly lit reticle visible to your dominant eye onto the primary image from your non-dominant eye. The result is you see a 1x image from your non-dominant eye with the reticle from your dominant eye overlaid onto it. As soon as the reticle is on target, your dominant eye will take over and you will zoom from the 1x of your non-dominant eye to the magnified image of the ACOG. The end result is the ability to rapidly engage targets at close-quarters, even though you are using a magnified optic. The key being the brightly illuminated reticle, and of course, leaving both eyes open. Rugged, lightweight, and compact, this model ACOG, without mount, weighs just 9.8 ounces. That is substantially less than a LPVO, some weighing in at over 21 ounces. As I wanted to shave weight, I binned the standard Trijicon mount and replaced it with a lighter QD piece from LaRue Tactical. With this, it weighs just 10.9 ounces and has an overall length of just 6.2 inches.

What do I like about this model? The ACOG is simple, extremely rugged, and requires no batteries. The fiber optic illuminated reticle is very bright and easy to pick-up. In lowlight, the tritium takes over illuminating the reticle enough to make it usable. Optical performance is good. While Trijicon lists the Eye Relief at a short 1.9 inches, I run mine at about four inches with zero issues and a full image. The 3x magnification is a definite advantage over a red dot once you move beyond 50 yards or so. At closer distances, I do not have a problem making rapid hits using the BAC feature. Past 200 yards, the bullet drop compensator on the reticle proves useful. Cons? There are indeed a few. One is price with a hefty MSRP of $1,476. The field of view is narrow, and this combined with the low 3x magnification makes scanning for, locating, and identifying distant targets more difficult. In very bright light, the fiber optics can make the reticle too bright. Although, a piece of 100 mph tape on the collector easily solves this. If you are in a dark area, such as a house, aiming out into a brightly lit area your reticle may not be brightly illuminated. The same can happen in low light if you are using a weapon mounted white light. Where the TA33 excels is when you need a lightweight and bombproof optic which will primarily be used inside 300 yards, but may need to reach further. If you desire, you can even piggyback a red dot on top. Now, if the price of admission is simply too high, Primary Arms has an economical compact 3x prism sight as an alternative. While its optical performance is not as good as the TA33s, MSRP is much more affordable at $320. I like Trijicon’s TA33 for certain applications. Most shooters in the US live in a 200- to 300-yard world which is ideal for the TA33. If you are looking to shed some bulk and weight, this mid-size ACOG may be something to consider.

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