Mammut Magic Sling Review

10th Jul 2017

Mammut Magic Sling-2

Slings have been around in climbing for, it seems, as long as people have been using ropes.  The first incarnations were just lengths of knotted rope and then somewhere down the line woven and stitched nylon started to be used.  Since then we've had space age fibres like Dyneema which have allowed slings to become lighter but just as strong.  Who would have thought, ten years ago, that we would be using 6 or 8mm slings that could take a load of 22kn's!  The downside to the continuing drive to skinniness is a drop in durability and, while skinny slings knot easily, there is a drop in strength as a result.

Mammut have recently produced a sling which they claim to be highly abrasion resistant and, whereas knotted Dyneema slings are said to potentially lose up to 40% of their strength when knotted, these new slings only lose 20%.  Mammut kindly sent me one to test.......


The secret to the Magic sling is really in its construction.  Rather than a women fibre that is stitched together, the Magic's are constructed from a core of multiple loops of Dyneema fibre that are then encased in a durable nylon sheath.  This reduces strength loss when knotting but also offers exceptional durability and reduced UV degradation.  We have tested a 60cm model but Mammut are also producing a 120cm sling and a multi looped 120cm chain (which we hope to test soon).

In Use

I am not claiming this is a long term test, but over the last couple of months the Magic Sling has been out on lots of our recent Peak District climbing courses and has done time in Snowdonia and Northern Spain.  This means time spent on rough gritstone as well as limestone and rhyolite. It has meant threading behind boulder chokes and being used to extend protection pieces.   It's a good cross section of rock types and environments and I calculated that so far it has had over 50 days use by at least 10 instructors and easily as many clients.  

The Magic Sling is 12mm diameter and so, if you are a skinny Dyneema user, it will feel pretty chunky.  It is also quite thick (when you pinch it between your fingers) as it obviously has the core and sheath to add bulk.  It is also, as result, quite stiff - although it has softened up somewhat with use.  I generally like quite stiff slings for general use because they can easily be poked behind blocks and through small openings.  It also means it will be rigid enough so you can reach up over your head to lasso that out reach spike.

The thicker and more rigid tape does means it won't lie over small nubbins of rock as easily as a very soft sling, but it is reassuringly beefy enough to add confidence when used in any position where the sling could then rub over rough rock.  

So far, beyond a little furring up in places, the Magic Sling shows little signs of wear and tear.  Even better, of course, I know that it is only wear to the outer sheath that is visible and it would only be damage that got through this outer sheath that could compromise the core (like a rope).

The other key advantage Mammut point towards with this sling is the extra strength factor when knotted.  It is sobering to think that a sling can lose 40% of its strength when knotted and in lots of climbing applications it is impractical to not knot slings.  I obviously can't load test a sling to confirm Mammut’s claims, but it seems reasonable that a continuous loop will be stronger than a woven material.  I have no reason to doubt their claims either of course as I'm sure lots of testing time has gone into bringing this product to market.

In terms of knotting, it is easier to comment on how easy the sling is to actual tie the knots into them. As previously mentioned, a 12 mm sling which is also a core/sheath combo is going to be fairly chunky and so, tieing a knot will result in a bulkier knot overall.  It certainly isn't a problem tieing knots in the Magic’s and I've tested it with overhand knots, clove hitches, figure of 8’s on a bight and even used it happily with a Klemheist knot on a recent self rescue course.  The upside of the stiffer fabric is that the knots are very easy to untie even after they have been loaded.  So, pros and cons, but it is also nice to know there’s that extra safety reserve with the increased knot strength too.  

In terms of manufacturing quality, the Magic Slings are everything you would expect from Mammut.  The stitching is perfect and the slings look made for a tough mountain life.  The 60cm sling I was sent is available in a red colour and there is also a 120cm length available in blue.


Sometimes the simplest ideas are the best and the Magic Sling is a good example of that adage.  To be clear, there is a lot of technology incorporated into this fabric loop, but in essence using multiple loops of Dyneema fibres encased in a tough sheath is a simple enough idea.  Mammut have managed to create a product that does its job well whilst also having added the added safety elements of increased knot strength and a long lasting sheath.  Bravo Mammut.

The Magic Slings cost £11 for the 60cm version and £14 for the 120cm model.  More details are available on the Mammut website here and please do check out Mammut’s handy video below......

Posted by Paul

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