Primary Arms GLx 10×42 Review : Field Tested!

Primary Arms GLx 10x42 Review

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The Primary Arms GLx 10×42 are mid-level binoculars from Primary Arms, a company better known for making guns and gun parts. Its optics division turns out pretty good stuff at reasonable prices as well.

We will cover these below in more detail. Here is a quick summary of what this optic is and is not. It is a fixed 10x magnification. The inside is a roof prism setup and with extra-low dispersion (ED) glass.

Keep reading to learn more about these binoculars to decide if they are for you.

Are the Primary Arm GLx 10×42 a Good Buy?

Primary Arm GLx 10x42

This set of binoculars represents a good buy as you get a number of advantages over similarly sized binoculars. There are some tradeoffs compared to smaller and bigger binoculars, but that is the case with all optics.

In addition to the fixed 10x magnification, roof prism setup, and extra-low dispersion glass, these are medium frame binoculars with a mid-sized 42mm objective bell. It is 5.5 inches long and comes in at 23.74 ounces or just a tad under 1.5 pounds. 

Features of the Primry GLx 10×42

Let’s take a deep dive into this binoc’s features to see if it works best for what you want do.

1. Magnification


Binoculars are meant to magnify whatever you are looking at. The GLx 10×42 offers a fixed 10x magnification. Most binoculars have a fixed magnification level.

In the GLx 10×42 , this means your field of view (FOV) is 341 feet at 1,000 yards. At 100 yards, the FOV is 34 feet.

The average whitetail is 6 feet from nose to tail. So you could fit about 5 and half whitetail nose to nose at 100 yards and see all of them. It’s worth noting that that is on the lower end for binoculars. The maximum magnification current held by a set of binoculars is 80x, eight times that of the GLx and more than double the maximum zoom on the best rifle scopes.

As the magnification factor goes up, so does the cost when you are dealing with quality optics.

Here is the tradeoff:

  • More magnification drives the cost up.
  • More magnification increases the size and weight.

2. Glass


Magnification is great. The glass and internals inside are equally important and as the magnification increases, glass becomes more important.

Binoculars need quality glass inside to deliver sharp images to your eye. The GLx offers ED glass. This increases the amount of light going through the tubes to your eye.

In low light conditions, ED and coated lenses are important. You need all the light you can get to make out what may be camouflaged or hiding in the shadows.

ED glass also reduces the color halo that may appear around distant objects. Cheap glass will create this halo effect as the light beam separates as it moves through the binoc tubes on each side.

If you are trying to find something small, that light halo may be enough to hide it from your sight through the binoculars.

The objective lens, or the front bell, is 42 mm. This is a medium-sized lens

Bell size matters because this is where light is collected and transferred through the tube and the internals. The more light the binoculars gather, the brighter the scene will be. Small bells mean less light. These binoculars do not function well in low light. As the bell size increases, so does the light-gathering ability.

Here is the tradeoff:

  • As the bell gets bigger, the cost of quality binoculars increases.
  • As the bell gets bigger, the weight increases.

3. Prism

The GLx is a roof prism binoc. Binoculars rely on a prism to transfer the light from the main tube to the eyepiece. Prisms are either a roof prism or a porro prism. 

The roof prism is superior when you need lots of magnification. It does add some expense and you get a slightly narrower field of view. Given the same front bell and the same lighting, the image in a roof prism will be a bit brighter than a porro.

The porro offers a wider field of view and sometimes a better image quality. It is less expensive. Given the same front bell and same lighting, the image in a porro will be a bit darker than a roof prism.

When high-quality glass is used, the image quality is nearly identical.

The porro bounces light off reflecting surfaces inside the binoculars.

The roof prism is best for:

  • Long range spotting
  • Daytime hunting
  • Evening hunts

Other advantages to the roof prism are directly related to the construction.

  • Lighter because less glass
  • More compact, again less glass
  • Better waterproofing because fewer seams and joins
  • More durable because fewer parts

4. Size

Is the Primary Arms GLx 10x42 Worth Buying?

Size matters a lot, especially when you are doing a stop-and-stalk across the plains or in the mountains. Every ounce of extra weight is something you will haul all day and then back to camp.

At just under 1.5 pounds, the GLx weighs about as much as a good long range rifle scope. Yes, you can get lighter scopes, but at the expense of less magnification and poorer image quality.

You can get heavier scopes, but that weight will tell on you at the end of a long day.

For instance, if you are sitting in a stand with a view out to a few hundred yards, weight and size are less of an issue, except for heading into the woods and out again. If you shoot a trophy, then you have to manage your wall hanger, gun, binoculars and everything else. Size does matter again.

On the other hand, if you are just sitting and watching wildlife, say in a park, size does not matter a lot except for fatigue. Holding up a giant set of binoculars for hours will wear your arms out.

The binoculars are 5.5 inches long and 5.5. wide. The front bell is 2 inches across, the biggest size for this measurement.

This is not a compact set of binoculars, nor is it a large set. It is actually on the smaller size, given the magnification range.

Advances in the optics industry over the years have let scope and binoc makers reduce the size of their products while improving them at the same time.

Here are the tradeoffs:

  • Medium weight means medium-level performance
  • The size is manageable for most situations
  • It may not be enough for scanning a mountain across the valley
  • It may be too much for sitting in a bottom with limited visibility
  • It is ideal for ranges from 75 to 300 yards

5. Use

What are you looking for in a set of binoculars? How will you use them? 

The GLX is ideal for:

  • Short to medium-range hunting
  • Checking targets to 100 yards when sighting in guns
  • Watching ball games from the upper seats
  • Bird watching in parks and places where the birds come close

Primary Arms GLx 10x42mm

The price of Primary Arms GLx varies, so check the latest price at

6. Other Notable Specificationss

  • Lifetime Primary Arms Warranty
  • Soft case and neck strap
  • 2 meter close focus
  • 6.5 degrees angular FOV
  • 15.2mm eye relief
  • Magnesium body with rubber coating
  • Waterproof
  • Neutral grey color

Is the Primary Arms GLx 10×42 Worth Buying?

Is the Primary Arms GLx 10×42 worth buying? In short, yes. PA makes good optics for the money. These binocs will serve you well under most circumstances.


Are the GLx binoculars waterproof?

The GLX binoculars are waterproof. Drop them in the creek and you have nothing to worry about. Get rained on, and you have nothing to worry about.

Does ED glass matter in binoculars?

Yes, ED glass matters in binoculars because it provides a sharp, clear picture and transmits as much light as possible. Cheaper glass gives distorted views and does not provide as bright of a picture.

What is the GLx warranty?

Primary Arms offers a lifetime warranty on the GLX. They will repair or replace it with a similar set of binoculars at their option.

Which is better a roof prism or a porro prism?

The better choice between a roof prism and a porro prism depends on your needs. If cost is a factor, the porro is usually cheaper. Given the same quality glass, the image quality is about the same.


If you are looking for a good set of mid-range binoculars at a reasonable price, the Primary Arms GLx is a great choice.

It’s got a rugged construction, waterproofing and ED glass make this a clear choice for hunters who spend time looking for game at medium ranges. It is also excellent for birders where the birds get close. Sports fans in the cheap seats will pull the action in close.

If you need binoculars for everyday use, this is a great set to own.

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