I received my Critical Mass SARC in October 1997.
Design: internal frame/internal frame
Size: Approx. 7,800 - 8,000/5,000 cubic inches
Number of Pockets: 1/0
Max. Load Carried: 71.5 lb./61.5 lb.
Height of Owner: 5'8"
Price Paid: $575 US/$419 US
I received my Critical Mass SARC in October 1997. After purchasing an Inex Alpineer Bayonet a few weeks earlier (see my review of that pack elsewhere), I decided to purchase a smaller McHale bag.
At a cost of $419 and total volume of about 5,000 cubic inches, this pack meets the majority of my load-hauling needs. The stated extended volume of this pack in the literature I received is 3800 cubic inches, but that has to be a misprint since the figure is inconsistent with the other volume figures presented. That is, even though the Critical Mass SARC is designed to be larger than the standard SARC, it is stated to have the same extended volume. Additionally since you can order a SARC with varying sizes of lids, I suspect the lid volume is not taken into consideration in the stated volume.
Relative to the other volume figures given, I estimate the maximum volume of the main bag to be about 4300 to 4500 cubic inches. The lid is the standard size available with a Critical Mass SARC with a volume I estimate to be approximately 600 cubic inches. This places the total pack volume at about 5,000 cubic inches.
The most weight I have carried so far in the pack is 61.5 pounds (that is the combined weight of the pack with its contents). Usually, my loads with this pack are in the 45 to 50 pound range. However, even the 61.5 pound load felt rather comfortable to carry. The frame controlled the heavier load admirably, and my usual loads are completely painless.
The bag of my Critical Mass SARC is comprised of a combination of 840 denier untexturized (junior ballistics) nylon in the (double layer) bottom, lower third, and harness side with 1000 denier Cordura Plus nylon for the rest of the main bag and lid.
The bag contains no exterior pockets. All patches are stitched onto the pack as overlays.
The patches are constructed of 840 denier untexturized nylon. As with McHale's other packs, you can select a different combination of fabrics so long as McHale has them available.
The interior of the bag has a shelf about one third of the way up that is held in place with ladder-lock buckles for easy replacement or removal. The interior also has two compression straps for the sleeping bag in the bottom compartment and about a seven-inch extension sleeve at the top. (The extension sleeve appears to be made of 420 denier untexturized nylon that is coated for water repellency.) The bottom third of the pack is unlined but the entire pack interior is well coated with a water-resistant substance.
As with my Alpineer, the overall bag construction is superb. Again, the seams are well stitched, and there is no loose fabric anywhere.
The pack's frame is comprised of two vertical stays bolted at their base to a curved, horizontal stay that extends along the pack at hip level. It is this curved, horizontal stay also present on all Alpineers that distinguishes the various Critical Mass SARCs from the non-Critical Mass SARCs. This design adds considerable strength to the SARC frame relative to SARCs not containing this additional, horizontal stay, and since I weigh 140 pounds and am 5'8" tall, it is the primary reason I opted for a Critical Mass SARC as opposed to a non-Critical Mass SARC: I wanted the extra frame support.
As with all McHale's packs, all stays are composed of 7075-T6 aluminum.
The vertical stays are outwardly migrated at the base of the pack and extend about 3 or 4 inches above my shoulders with an unloaded pack. The shoulder pads themselves, which are not part of the Bypass harness system with this particular model SARC, are attached to the top of the vertical frame stays and not only function to manage some of the load but also function as the pack's stabilizers. This system does not permit the load-carrying capability or grant the comfort affordable with the Bypass system, but then this (Guide) harness system is not intended to be used with packs designed to carry really large loads. The Critical Mass SARC is one of McHale's smallest packs.
I have to emphasize the comfort of this pack with fifty-pound loads. The fact that the vertical frame stays extend above the shoulders and are manufactured from 7075-T6 aluminum alloy are the main reasons the pack can so comfortably handle such weights.
This is precisely where the internal frames of most other manufacturers fail in their designs. The frames are too short, too weak, or both. Those design flaws cause packs carrying heavier loads to collapse onto the tops of your shoulders. If the frame is not long enough to extend above your shoulders, then the pack weight invariably tugs on the shoulder straps pulling the shoulder straps down onto your shoulders. In that situation it does not matter what material the frame is made from. The frame has to be both long enough to extend above your shoulders and strong enough to flex but not collapse under the load you carry.
The frame of the Critical Mass SARC permits you to hip load most of the weight, and the weight managed by your upper body is kept off the tops of your shoulders by the strong and long frame. The frame controls the load, not your shoulders. This is the way all internal-pack frames should be designed, but only McHale's are. Since my SARC came with the Critical Mass frame, it also came with a full-wrap belt (see my review of the Alpineer for more details).
As with my Alpineer, my Critical Mass SARC arrived with one minor flaw: the pack's removable back pad did not extend low enough to prevent me from being poked with sharp objects in the bag. Also as with the Alpineer's pad, the bottom edge of the Critical Mass SARC's back pad was stiff enough to cause minor irritation when wearing only a shirt. I successfully dealt with this matter as before by telephoning McHale and Company with the request to construct another pad to my specification, and they again readily agreed to the substitution at no cost.
I now own two, perfect McHale and Company packs with which I could not be happier. I never will purchase a backpack from any other manufacturer.
In fact, 2.5 years ago I retained a smaller Dana Design Bomb pack that I still use for carrying loads under 30 pounds or for traveling on airplanes (as carry-on luggage) but in which I occasionally carry loads exceeding 40 pounds. The pack is great for loads under 20 pounds, but I find that even 25 pounds will pull down on the shoulder pads to such an extent that I feel some discomfort after about 30 minutes. The Dana pack is not a rucksack but contains a frame comprised of a single vertical 6061 series aluminum frame stay reinforcing an HDPE frame sheet. However because the frame is so short, the frame just as well might be non-existent; it is not at all effective in controlling the load despite Dana Design's hype.
I have become so disgusted by the fact that carrying 25 pounds in my Dana pack is not as comfortable as carrying 50 pounds in my Critical Mass SARC, that I recently decided to purchase my third McHale pack: a Zero SARC, which is McHale's smallest pack. Soon after I receive my Zero SARC, I intend to sell or donate my final, remaining non-McHale pack. Good riddance.
Update: March 21, 2000
These notes are submitted in elaboration of and correction to my recent reviews of the McHale & Company Inex Alpineer Bayonet and Critical Mass SARC. For too many years I rarely questioned the persistent discomfort in my shoulders and along my collar bones (as well as waist strangulation) because I learned to accept that discomfort as normal. Over time, I blocked most of the pain from my immediate awareness because the discomfort was expected. It was not until I began wearing McHale packs that I experienced a truly pain-free, load-carrying (internal-frame) backpack. It also was at that time that the discrepancy between wearing a McHale and wearing anything else made me cognizant of just how much pain I had been blocking all those years. When I now look at other manufacturers' packs, I cannot help viewing them with ridicule.
Unless you have worn a McHale pack, you might think I am being unreasonably critical of other manufacturers' backpacks. If I had read these reviews 5 or 6 years ago, I also might have arrived at that conclusion. However, it took owning only one McHale pack to change my viewpoint to what you read here. More information on McHale backpacks can be obtained at http://www.mchalepacks.com. All McHale packs are tailored to your needs and specifications and manufactured in the United States.
In my previous reviews I neglected to state that the Inex Alpineer Bayonet and Critical Mass SARC come standard with a summit flap that either is integrated into the lid (SARC) or comes as a separate, attachable piece (Alpineer). The lid can be removed and summit flap employed to reduce the overall pack weight while still completely covering the top aperture.
Both packs are designed such that the area below the shelf and above the sleeping bag is large enough to store a good deal of clothing. This makes access to that clothing via the horizontally arced zipper easy.
All McHale's Critical Mass SARCs and Alpineers utilize a full-wrap hip belt that generally comes with twin, cam-lever-action buckles. Although side-release buckles are available upon request, I did not request them since they are not as sturdy for heavy-load carrying or as easy to open or adjust as cam buckles. The full-wrap belts also generally come with handles and gear-attachment straps located on the exterior side of the belt above the handles. The method of bolting the belt to the frame (through the pack bag) permits relatively easy belt substitution.
Additionally, all McHale's Critical Mass SARCs and Alpineers come with an adjustable and detachable lumbar pad, the pad is not required if you carry a sleeping bag in the sleeping bag compartment. The sleeping bag itself functions as the lumbar pad. The vertical frame stays do not impact your pelvic structure since they diverge from one another at the base of the pack to straddle your pelvis. This is one reason McHale packs are so comfortable with heavy loads.
In my review of the Alpineer, I wrote about requesting and receiving a longer back pad that fully protected my back from the pack's contents. I incorrectly stated that "the bottom edge of the pad ended very nearly where the top edge of the hip belt began (that is, the back pad and hip belt edges almost were flush with one another)." I should have stated that the back pad's bottom edge is nearly flush with the top edge of the lumbar pad. If the lumbar pad is replaced with a sleeping bag, then the sleeping bag fills the gap. With the longer back pad the entire harness side of the pack provides something soft - - either foam padding or sleeping bag - - to shield my body from the pack's remaining contents. The longer back pad is long enough to just extend to the bend in the vertical frame stays but no farther. If the back pad extends down past the bend in the frame stays, then the frame stays could thrust the lower part of the pad into the lower back, which could result in discomfort.
I especially recommend a McHale pack to people who currently look upon the world of internal-frame packs with disfavor. If you cannot afford to purchase multiple packs for your needs, investigate either the smaller Alpineers or the Alpine II - - both the Critical Mass and non-Critical Mass versions. These selections possess the Bayonet stays that permit detachment of the upper portion of the vertical frame essentially providing an owner with two, differently sized packs for the price of one.