In this post, I review the Hyperlite Mountain Gear 3400 Southwest, an ultralight backpack built for durability and simplicity.
On a humid day in July, my husband set out to thru-hike the Appalachian Trail. A seasoned hiker myself (I completed the AT in 2015) I offered my full breadth of wisdom as he packed his belongings. He planned to use a heavier Osprey backpack when I offered up my Gossamer Gear Mariposa, about pack that is about 3 pounds lighter, but he declined.
A month later the inevitable happened. “Can you send me your pack? Mine is too heavy”. I mailed him my pack and smiled as I finally had an excuse to buy a new one. After doing my research I ordered the Hyperlite Mountain Gear 3400 Southwest online and had it shipped to me.
Why I Bought 3400 Southwest
There were three main considerations I had when I started my search:
- Durable — I was looking for something slightly more durable than my Gossamer Gear, which is incredibly comfortable and lightweight, but I had managed to rip in several places.
- Ultralight — I wanted a pack that would be considered ultralight, but could also be used on comfort trips, where speed wasn’t the goal and beer typically makes several appearances – so it had to be sturdy and not have a low weight limit
- Waterproof — With a waterproof outer material, I don’t have to bring a pack cover for when it rains, further lightening the load.
If you’re interested in learning about the other packs I considered in my search, read: The 10 Best Lightweight Hiking Backpacks for 2020
3400 Southwest Specs
Hyperlite Mountain Gear makes high-quality ultralight outdoor equipment like tents and backpacks. All of their products are manufactured in the USA.
Click here to view the 3400 Southwest on the Hyperlite Mountain Gear website.
Important Specs:
- Weight – 32.11 oz
- Volume – 55 liters
- Materials – Waterproof Dyneema
- Best use cases – thru-hiking, 2-4 day backpacking trips
Where to Buy:
3400 Southwest Full Review
How I tested
I tested the 3400 Southwest over 4 backpacking trips and 80 miles — a total of 11 days and 6 nights. I hiked in terrain in the Grand Canyon of Pennsylvania, along the Appalachian Trail in Pennsylvania and Maryland, along the AT in Shenandoah, and down the Approach Trail from Springer Mountain in Georgia. During the trips, temperatures were mostly mild, with the exception of one trip, where we experienced frigid weather and a full day of sleet and snow.
Pack fit & Adjustability
Fit is the number one concern for any pack, as this relates directly to comfort. Ordering the pack online, I was slightly concerned about the fit, so I made sure to measure my torso length and order the pack size that HMG recommends for me.
Some packs come with an adjustable back panel, allowing you to raise or lower the shoulder straps – but this isn’t the case with the 3400 Southwest, so ordering the correct size is important.
The hip belt fits comfortably with plenty of room to adjust. The hip pockets are quite large, which I was happy about because I wanted the widest part of the hip belt to wrap around my hip bones. After tightening the hip belt, I adjusted the shoulder straps. I had to pull this quite short, but there was still room to adjust smaller if needed.
My only complaint about the fit is that the chest strap can’t adjust as high up on my chest as I would have liked. This is a common issue with unisex backpacks.
Comfort
One major factor in comfort for an ultralight or minimalist pack like the 3400 Southwest is how you pack it. On my first trip with this pack, I packed poorly, with heavier equipment near the top. This caused the shoulder straps to pull back hard around my collarbone, and left me a little sore.
On my second trip, I made sure to pack more carefully and was impressed with how much better everything felt.
While the straps on the 3400 Southwest have less padding than some other packs, they feel strong and durable, and the weight is distributed well, as long as you pack with comfort in mind.
I should note this pack is meant for lightweight loads. If you plan to pack 30 pounds worth of equipment, you would be better suited with a heavier, but more padded backpack. I think that 25 pounds or less would be best for the 3400 Southwest.
Riley shows off the pack straps 
Andrew and I pack testing in Shenandoah NP
Packability
The 3400 Southwest has a rolltop lid that makes this pack very versatile in size. On short trips with less gear, rolling the lid tight will allow you to fit the pack to your load. For a 2-3 night trip, I can comfortably fit all of my things inside the pack and be able to roll the top down a few times (which also helps keep everything waterproof).
On one occasion I hiked with a novice and ended up carrying far more equipment and weight than I usually do. While my shoulders were quite sore after this trip, it was very helpful to be able to fit more gear on the fly.
The outer pockets are also surprisingly roomy, with one water bottle pocket on each side, and a larger pocket on the front of the pack. I will typically add a water bottle to one side, and insert my tent poles into the other side. The larger pouch on the front is great for storing items that you want quick access to, like a jacket.
I love the closure system on this pack, too. There are no zippers on this pack with the exception of the hip belt pockets. The top closure is velcro. Then you roll down the top, and clip it down on each size. The y-strap closure comes over the top of the pack and is great for tightening down the load. You can also use it to strap down accessories, like a big puffy jacket or large sleeping pad.
The 3400 Southwest also comes complete with an ice axe loop. I don’t have an ice axe, but I’ll typically use this loop to help carry my trekking poles if I’m not using them.
Roll-top open 
Roll-top closed and straps buckled 
Water bottle pocket 
Large front pouch
Durability
The 3400 Southwest is constructed entirely with Dyneema fabric, which is known for its durability and water repellency.
In my testing, I used this pack as I normally would. It was scraped against rocks, thrown on the ground, sat on top of, and generally abused. With my previous pack (the Gossamer Gear Mariposa) – I often found new rips and holes in the nylon fabric — but the 3400 Southwest stood up to the abuse and I have yet to find a hole or even a scratch.
Waterproofness
As we awoke on the last day of a 3-day backpacking trip through the Grand Canyon of PA, it started to sleet. And it didn’t stop. For 10 miles the sleet and snow descended upon my naked pack (no pack cover). So how’d the 3400 Southwest hold up? In a word, perfect. Everything inside the pack remained dry.
Is the 3400 Southwest the Best Ultralight Backpack?
In conclusion, I love this pack and am very happy with the fit and comfort. If you are new to backpacking, make sure to keep in mind that you will want to pack fairly light and the weight in the pack must be distributed evenly for this to be comfortable. This is a great pack for anyone but the folks that will get the most use are experienced backpackers out for a few nights, or thru-hikers who are looking for a durable lightweight backpack.
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2 comments
[…] Read our full review of the HMG 3400 […]
Again, great review. I’m going to focus on dialing in a lower base weight so I can get below 30 pounds with food and water. Once I’m there I guess I’ll make my final decision on either the HMG or the GG Mariposa. Thanks again.