Chest Rig Review: Spiritus Systems Mk V Chassis

Let’s get right to it – I bought the Mk V chassis mainly because it was relatively inexpensive. I already own the Spiritus Micro Fight Mk IV chest rig, so adding another chassis to the collection for the sum total of £50 at the time felt like a complete no-brainier… Actually, it still does.

Having owned the Mk V Chassis for a couple of months now I’ve had the opportunity to run it in a few different combinations, and I’ve come to the conclusion that a lot of people might be looking at the Mk V in the wrong light… There’s a lot going on with this product, and pairing it with the CCS pouch that it’s regularly seen with, is only one of many ways to use this chassis.

The Thing 2 – If I stuck a CCS pouch in the front of this set up, I’d have some serious carriage capacity for a micro rig.

Let’s look at the overall design – The Mk V Chassis consists of a single stack, triple width modular magazine pouch with hook and loop interior customisation and laser cut MOLLE along it’s front and sides.

Where the Mk V Chassis differs from every other Spiritus Systems product to date, is it’s extensive use of PALS/MOLLE. There’s so much on the Mk V that it covers the entire visible surface.

The front face of the rig has some serious stitching… Any attached pouches should hold firm.

But Y Tho? Isn’t the beauty of Spiritus Systems’ line up that it doesn’t rely on a grid attachment system, along with it’s inherent limitations? You’re absolutely right. But, there’s also a strong case to be made for MOLLE:

You don’t have to worry about it tearing off, it makes zero noise and there’s a 20 year back-catalogue of pouches that’ll fit directly to it.

By using “negative space” laser-cut MOLLE, Spiritus have also minimised the potential for any unwanted bulk, weight, or loss of strength. Adding MOLLE to their Mk V Chassis actually costs the end user very little indeed.

The pouch appears to be made from 500/1000d “squadron” laminate (effectively a sheet of 1000d and 500d cordura that have been bonded together) offering an incredible amount of toughness in a light and flexible fabric. The entire pouch is laser-cut from a single sheet of this laminate, being strategically folded and sewn into shape after it’s exterior and interior hook and loop fields are added.

The bottom of the Mk V is left open at both corners, allowing for rapid drainage, whilst also making the pouch incredibly easy to sew together. This has contributed to Spiritus’ overall streamlined approach to keep production costs down and retail the Mk V at a lower price point than I’d have expected.

Note the twin holes for shock-cord attachment.

In theory, there’s more work that goes into the manufacturing of a JSTA or SACK with their inherently more complex designs than this particular chassis, so it makes perfect sense that this costs a little less than either of those products.

The front face of the Mk V Chassis is dominated by a full sized loop field, with laser cut MOLLE type slots running through both the loop field and laminate layer. An internal loop field sheet provides the internal baffle, ensuring zero interference from the external MOLLE to the interior hook/loop inserts and vice versa.

In addition to the front panel, laser-cut slots and holes are strategically positioned along every edge of the Mk V. This allows the use of shock-cord to retain items such as CAT Tourniquets, comms cabling or in the case of the MOLLE slots, additional pouches.

You’re able to fit three CATs on the bottom and sides of the Mk V. You could carry another three or four on the front if you really needed to!

The rear of the pouch is mostly what you’d expect, an edge to edge sheet of hook velcro provides the primary attachment for the Mk V Chassis to a wide variety of chest rigs and plate carriers. To further it’s attachment options, six loops are formed within the laminate so that buckles may be fitted directly onto the Mk V.

A blank loop field sheet is supplied for comfort when using the chassis as a stand-alone chest rig.

Two male and four female buckles are supplied, enabling the Mk V to be fitted to existing harnesses offered by Spiritus themselves or even their competitors. The male buckles are pre-fitted to the upper loops and at the same standard width we’ve become used to seeing, four additional female buckles are supplied unfitted within the packaging.

One column of molle down each side does mean that you could fit a pistol or very small radio pouch on either side… At the expense of aesthetics.

The interior of the Mk V is lined front and back with loop material, providing the same insert and accessory compatibility as the Mk IV chassis. There isn’t much I can say about this that hasn’t already been said, it’s versatile and allows for almost unlimited customisation and future proofing of the entire chassis system.

Along the top edge of both front and rear faces of the Mk V, you can clearly see an additional row of laser cut holes. These holes are perfect for adding shock-cord retention, something that previously could only be achieved on their micro rigs via third party modification. Not everyone will choose to use these, but for those who specialise in maritime or airborne environments, these can often be a dealbreaker.

Spiritus do offer a pull tab kit, but I actually prefer these Haley ones. S&S Precision pull tabs are also a great choice!

And that’s about it… there isn’t really much more to say about it’s construction. But the most important factor in my opinion, is in how this rig is actually used.


Spiritus micro fight rigs are often seen loaded up to the gills with as much stuff as is humanly possibly to fit to a micro rig, and I’m as guilty as the next guy when it comes to loading out my chest rig. However in my opinion, it’s the (not nearly as often seen) pure minimalist approach that will play to the Mk V’s strengths.

Using the Mk V with just a harness and back strap makes for a very low profile rig indeed. Almost as compact as their Bank Robber Rig, but with the added ability to run 7.62 or SMG mags. You retain the ability to attach a tourniquet and an option to scale it up vertically with a SACK or laterally with wing pouches should the need arise.

Unlike it’s predecessor and majority of it’s competitors, you can also attach pretty much any nav board or EUD bracket (prominently those made by Juggernaut or Kagwerks) without any third party modification.

The Mk IV shown with a Juggernaut phone case attached via an AXL adaptor panel… Not something you’ll need with the Mk V Chassis.

Any magazine that will fit within Spiritus’ inserts will fit within the Mk V, it’s just a case of finding the right insert for the job. I’ve personally used the triple 5.56 insert for both M4 and AKM magazines as well as the quad SMG insert for MP5 magazines.

AKM mags fit… Just! But not something I’d recommend.

It’s a bit too tight really for the 7.62×39 AKM magazines, but they will fit if absolutely necessary. A double 7.62 insert is also available for those carrying something with a bit more poke, although you’ll be limited to 2 magazines with that particular option.

The Mk V adds a whole new layer of customisation to the concept of micro rigs, whether it’s on the smaller end of the scale and merely adding additional magazine retention, or by adding otherwise difficult to attach items such as navigation panels or large sustainment pouches, the Mk V appears to fill a very valid gap in the market.

HSP D3CRM (Top), Spiritus Mk IV (Middle) Spiritus Mk V (Bottom)

With time, I’m confident that we’ll see support grow for this pouch, not just through Spiritus, but also third party manufacturers looking to add their own little widget onto the base product.

Would I recommend the Mk V? For anyone looking at an additional base for a low profile chest rig or placard, it’s hard to find reasons to not recommend the Mk V. Certainly if you’ve already invested in the Spiritus eco-system, it’s an easy yes.

Although it looks slightly larger than the Mk IV, the Mk V is almost identical in both width and height. it’s only around half as deep though…

If you’re yet to buy a placard or chest rig, you’ll need to factor in the additional costs of inserts/straps as the Mk V chassis is currently only available as a standalone item. I will concede that Spiritus probably subsidise the cost of their rigs through relatively expensive elastic inserts and flaps, but once you’re a part of the eco-system, it all becomes a little easier on the wallet to add a bit here, another bit there.

Personally I’ll be keeping mine in it’s “bank robber” guise, perhaps in the future I’ll add the CCS pouch to it, but unless I find myself short on carriage space in the future, this holds everything I currently need.


The Mk V is available in the U.K. (and worldwide) through Tactical Kit, who remain the key European and worldwide distributor for Spiritus Systems outside the US. I bought mine from them and at time of print, they had the Mk V in all available colours with straps and inserts also available from stock.