Definitive Guide to Umarex Zelos

The Umarex Zelos is based on many modern "tactical" airguns. Its main receiver has an AR15 Grip, little to no forearm, and a minimalistic buttstock. Officially, it's a "bullpup" configuration with the magazine deep into the buttstock and the side lever positioned comfortably above the trigger on the right side of the chassis.

There's a long, 250cc air cylinder that runs parallel to the 26" rifled and shrouded barrel. The removable air cylinder, which has a max pressure of 250 bar, connects to the lower part of the receiver and feeds a regulated valve. There is a fill pressure gauge at the front of the air cylinder, which shows the current pressure in the cylinder.

Shooters can adjust the regulator by removing the air cylinder, loosening the regulator adjustment retention nut, and making small adjustments to the reg screw. The manual clearly describes the process. The gauge on the left side of the receiver shows the current regulator pressure.

If you plan to adjust your Zelos, please note that you will need to have access to a Chronograph so that you can accurately measure your modifications. Trying to make these kinds of adjustments without a "chrony" is very impractical, if not impossible.

While on the topic of adjustability, airgunners can also adjust the trigger travel and sear, trigger blade, and hammer spring. Again, if you like the ability to dial in your airgun, the Zelos gives you plenty of options, all of which are very well documented in the manual.

Here are some other key features. There's a 1/2 x 20 UNF threaded muzzle cap at the end of the shroud, perfect for attaching accessories to keep your airgun quiet. The .22 caliber model comes with two 20-round magazines, and the .25 comes with two 18-round magazines. There's a 21-slot picatinny scope rail for mounting your favorite optic and an 8-slot rail attached to the air cylinder for accessories.

The manual safety is located on the right side of the action above the trigger. The overall length is 36", and the entire rifle weighs a modest 6 pounds. Now, let's get our Zelos ready for the range.

Setup & Operation

Part of the setup is going to be picking an optic for your Zelos. You will want to get some nice glass for this airgun. As you will see shortly, it delivers on accuracy. Don't leave performance on the table by going with a low-quality optic. We used a Hawke Frontier first focal plane scope. The scope costs a lot more than the gun, but the Zelos performs way above its price point, so you are not overspending if you go with this class of optics. This will become obvious when we get to the accuracy portion of this guide.

The Umarex Zelos is a PCP airgun that requires high-pressure air to operate. There's a protective cover over the fill nipple at the front of the air cylinder. Once removed, you can connect a tank, compressor, or HPA hand pump to fill your airgun. Whatever your choice, make sure that you ONLY use clean, dry air. Moisture and other debris will foul your seals and can cause issues with your regulator. Hand pumps are not ideal unless you properly filter the air on the output side.

Once you've filled your airgun, it's time to load the magazine. For our tests, we shot the JSB 18.13 grain pellets. They proved to be VERY accurate and reliable. The magazine is easy to load. Simply rotate the cover clockwise, which will rotate the inner cylinder. Put a pellet in the back side of the mag skirt first, and then release the cover. Rotate the cover counterclockwise, exposing each pellet hole and loading in pellets along the way. It may sound complicated, but once you've done it a few times, it will be second nature.

To load the magazine, put the safety on and then cock the side lever, leaving it open. This will allow you to load the magazine into the buttstock. You need to load it from the right side. Once secure, go ahead and close the cocking handle.

Your Zelos air rifle is now ready to fire. Go ahead and select your target, release the safety, and gently squeeze the trigger. The trigger breaks at under 2 pounds. For those who want to adjust trigger pull, sear engagement, and travel, please refer to the manual, which will walk you through each process.

Performance & Accuracy

Having done this work for many years, it's still surprising when we take a product out of the box, and it just works. Years ago, we would have to spend hours testing to hopefully start getting decent results. But thanks to the modern manufacturing processes of today, most of the time, we can just air up our airgun, mount the scope, load our mags, and go. We are happy to report that our Zelos performed perfectly right out of the box.

Shooters should get 2 full mags from a 250 BAR fill. Our test model delivered an average of 945 FPS across 40 shots with only a 15 FPS spread and a standard deviation of only 3.5 FPS. It averaged 35.9 foot-pounds of energy across the string. Those are great numbers right out of the box. For those interested, our Zelos came to us with the regulator set to 1900 PSI. We did not make any modifications to the gun. All our results are from the factory stock setup and configuration.

Now, let's get to the meat of this guide. All those numbers and features are great, but can it put lead on target accurately? The short answer is a resounding yes. The Zelos may be one of the most consistently accurate airguns, at 50 yards, that we've ever tested. We are going to share a lot of groups here, mostly because these were all shot on the same string. Some groups had a single flyer. Was that a bad pellet or our mistake behind the trigger? Frankly, we are leaning toward "user error" because everything else was so spot on.

There was an average breeze during our shooting session, pushing our shots a little left. We did not adjust the scope or try to hold to the right of center; rather, we just let the groups fall naturally. Here are our results.

The first 5-shot group with one flyer landing low. The main group was sub MOA.

The 2nd 5-shot group at 50 yards. No flyer, CTC was a fraction over .5" CTC.

The third 5-shot group at 50 yards with one low flyer. This was the unfortunate trend of the day. The main group was sub .5" CTC making it sub MOA for 50 yards.

This was our 4th group and it came in well under .5" CTC making it SUB MOA at 50 yards.

This was our fifth group and another SUB MOA showing. Again, it was all during the same shooting session and on the same fill.

This was our sixth and final 5-shot group, with that errant low flyer showing up yet again. The main group is again well under .5" CTC, making it another SUB MOA showing.

As you can see, the Umarex Zelos PCP rifle can deliver consistent accuracy across the entire shot string. This is a rarity that we simply don't find that often. Maybe in $2,000+ airguns, but the Zelos, at the time of publication, comes in around $600 and is delivering these kinds of results.

Summing Up

There's not much more to say. Umarex has brought another incredible airgun to the market that delivers what modern airgunners are looking for. It's a bullpup with minimalist styling, adjustability, accuracy, regulated valve, etc. The Zelos checks all the boxes and does so at an unbelievable price point.

If you have more questions about the Zelos or would like help putting together your next airgun package centered around the Zelos and need help picking accessories, then please don't hesitate to give us a call. We are always here to help.