The new K4 backpack from Exo Mountain Gear was built for backcountry hunters by backcountry hunters.

Exo Mountain Gear K4 Backpack

Exo Mountain Gear is no stranger to big miles and heavy poundage. They’ve been producing backpacks for backcountry hunting since 2014 and have become a fan favorite among dedicated backpack hunters like myself. Exo was started by dedicated backcountry hunters with the goal to produce the best backcountry hunting packs on the market, and they’ve been focused on that goal since the beginning. Their new K4 Backpack is a shining example of that.

Overview

The K4 is the 4th generation of backpacks from Exo Mountain Gear and it has 3+ years of testing in its wake. Immediately after the release of the K3 backpack, Exo started working on the K4. From that time, they’ve come out with a totally redesigned frame and bag combo.

K4 logo of Exo Mountain Gear Backpack

This next generation of Exo Mountain Gear packs comes in sizes 3600, 5000, and 7200. These numbers more accurately represent the cubic inches for the main bag, not the bag + lid together. The lid adds an additional 648 cubic inches.

Detaching bag from backpack frame

And of course, like with all Exo Mountain Gear packs, the bag detaches from the frame. This is so the hunter can load meat directly onto the frame itself while having camp gear, etc. in the actual bag. A tailor-made system for backpack hunters.

New Features of the K4 Frame

The all-new K4 frame is rated to 150+ pounds and comes in at 2 lbs 15 oz for the total package(waist belt, shoulder straps, etc.). There are 4 interchangeable frame heights of 22”, 23.5”, 25”, 26.5” and 6″ of torso adjustment. With this new system, you’ve now got 5 different hipbelt sizes to choose from as well which are XS, SM, MD, LG & XL. Proper fit is essential for the performance of any backpack, not just an Exo. These extra sizes in the lineup make achieving that proper fit for a wider variety of folks more possible than ever before.

Hipbelt and Lumbar Pad

hipbelt of K4 backpack

Exo also redesigned the hipbelt and lumbar pad. Both seem beefier than previous versions, and the lumbar is stouter, resulting in a more secure fit. A new feature they added on the hipbelt is MOLLE webbing which is how you’ll attach accessories like their hipbelt pouch or new Nalgene holder. There is also MOLLE webbing on the shoulder straps which accommodate some upcoming accessories from Exo.

The Bag

taking spotting scope out of full length side zip pockets

New with the K4 are full-length side zipper pockets instead of the cinched top entry ones on previous models. With those zippers being located toward the front of the bag, a hunter can easily get in there when the pack is laying down. These are perfect for carrying a spotting scope, tent poles, etc.

Another difference between the K3 and K4 is the K4 now has a sort of dual-side stretchy pocket on each side of the pack. These used to be singular, but now it’s a two-in-one deal, which offers more opportunity for organizing gear.

Bag Attachment System

velcro tabs on backpack

And perhaps one of the biggest changes is how the bag connects/disconnects from the frame. What used to be a bat wing velcro system is now just a matter of two small velcro strips that run vertically with the two top stays of the frame.

undoing velcro tab on backpack

Undo your side compression straps and loosen the lid straps. Underneath, you’ll see a velcro tab(one on each side of the pack). Release those velcro tabs. Back the tabs out through the small loop they were seated in. Now, just pull the bag up and the two stays will come out from two small slots in the bag. That’s it.

From Prototype to Now – The Most Prototyped Backpack Ever?

prototype of Exo K4 backpack

Mid-2022 150 individuals were selected to test out prototypes of the new K4 backpack. I was lucky enough to be a part of that group. Probably the coolest part about this too is that packs didn’t just go out to folks in the industry. Exo was offering prototypes to random hunters that were trying to simply buy the K3 as well. One could say this might be the most prototyped backpack ever made.

From those 150 individuals, Exo gained an immense amount of constructive feedback. They took all of this into consideration for the final pack. Whether it was a pocket that was too tight or a part of the pack that squeaked, they addressed it.

To give an idea of the level of detail to the changes, here are just a few they made from prototype to now:

  • Lid – Lid pockets reconfigured. The prototype had 1 pocket on the front of the lid, now there are 2 pockets. One toward the back and a smaller one toward the front. The style of the zipper was also changed.
  • Full-Length Side Zips – Zippers have been lengthened, they reconfigured the pleat, and added more volume.
  • Lower Side Stretch Pockets – These now have more depth and volume. Exo also changed the cut and top binding to give easier access.
  • Lumbar Pad – The pocket for the lumbar pad was redesigned offering a slightly more cushy feel while keeping the same initial lumbar pad form.
  • Zippers – All zipper flaps have been removed which aids in usability and a smoother system overall.

As you can see, Exo pays attention to the little things.

My Experience with the Exo Mountain Gear K4

Idaho mule deer hunt with prototype of k4 backpack

I was elated to be one of the 150 individuals to test out the K4 prototypes and provide feedback. From August 2022 until January 2023, I hunted all over the western United States and even into Mexico with the K4 5000. In that time I packed out 2 mule deer bucks, a bull elk, and 2 coues deer bucks. The pack-outs ranged from just a quarter mile from the truck all the way to 8 miles deep solo with camp.

How Much Will Fit?

On the backpack hunting side of things, I was able to get 8 days with food and gear on the INSIDE of the bag. If I ran my food between the bag and frame, I could easily get 10 days out of this backpack.

Initial Impressions

Josh Kirchner loading meat onto the k4 frame

My initial impressions of the backpack were largely good. Exo has always done a fantastic job of progressing in the right direction at the right speed and this K4 was no exception to that. The new bag layout seemed like it would cater more to efficiency in the field, as did the brand-new bag attachment system to the frame.

Issues with the Prototype?

The side stretchy pockets seemed a bit tight on the prototype. It was difficult getting things in and out of them. And the lid was a bit loosey-goosey with the fit as it didn’t quite sit right. I also was wishing there was an additional pocket on the lid. The room on the inside was great, but having everything piled in one spot got messy. These things were all resolved in the final product.

The First Hunt with the Exo Mountain Gear K4

Heading down the trail on my first hunt of the Fall, one thing stood out immediately to me about the new K4. The vertical rigidity paired with the torsional range of motion it offered was very noticeable. It felt like the pack was more an extension of my body rather than a tool, which was a really nice feeling hauling a week’s worth of gear.

Josh Kirchner packing out a mule deer with the Exo k4 backpack prototype

In general, the functionality and practicality of the pack really impressed me. The new front-facing full-length side zippers made getting into those parts of the pack much easier. Detaching the bag from the frame was also incredibly easy, as was reattaching it.

During the pack-outs, the new lumbar pad, frame, and waist belt felt as amazing as amazing can feel with 100+ pounds on your back. I didn’t notice any rubbing either and everything felt very sturdy.

Is There Anything Wrong?

While this new K4 is about as close to perfect as a pack can get, nothing is perfect, and there are some downsides. Keep in mind, I’m really digging here for cons and none of these are deal breakers by any means.

Pricey

First, this backpack is pretty pricey. In order to slip into one of these bad boys you’re gonna cough up about $700 more or less depending on what size bag you go with. That’s a lot of money, no matter who you are. You are absolutely getting what you pay for here though.

Nalgene Holder

Nalgene holder of the K4 backpack

Next, the Nalgene holder is a nice addition, it really is. You don’t notice it at all when hiking. And reaching back to grab the Nalgene is quite easy. Now, I’m really nitpicking here, but putting the Nalgene back into the holder is a tad bit tricky. Because of how far back it sits, which is optimal for weight placement, you can’t see the holder. This means you’ve gotta kinda feel your way around to get the bottle back where it needs to be. Along with that, the top of the Nalgene holder is slightly smaller, another beneficial design aspect, but it requires more precise “aiming” to get the bottle back into the holder. This isn’t a huge deal to me, because I rely mainly on a water bladder for on-the-go hydration. And in the end, I’d rather have the Nalgene holder there than not.

Pros

  • Carries heavy loads extremely well
  • Excellent torsional flexibility(pack moves with you side to side)
  • Practical new bag layout
  • Very easy to detach and reattach the bag from the frame

Cons

  • Pricey – On average $700
  • Nalgene can be hard to put back in the holder while hiking

Final Thoughts on the Exo Mountain Gear K4

I snagged my first hunting pack ever for around $50 from the local sporting goods store many years ago. After I got my first animal down, it because very apparent how useless that backpack would be past carrying some water and a pb&j.

Josh Kirchner glassing for bears wearing the Exo Mountain Gear k4 backpack

From that point forth, I vowed to always have a quality pack that would not only let me carry what I needed but also haul meat. Sifting through everything the market had to offer at the time, I landed on an Exo Mountain Gear backpack. Since then an Exo has always been on my back helping me do what I love to do.

The K4 to me is a representation of what staying the course gets you, just like in the field. It’s about the long haul. It’s about progression. And I can’t wait to see what else Exo Mountain Gear comes up with in the future. Until then, this K4 is one of my new best friends in the field.

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