1.0 Introduction

When I was researching this review about the Magpul MOE SL butt stock, I discovered that the company now refers to its venerable CTR as a ‘legacy’ item.

That doesn’t make the CTR any less aesthetically pleasing, battle proven or timelessly classic. However, it does imply that Magpul has engineered a successor to the CTR – and indeed they have.

The next evolutionary step is the MOE SL – or Magpul Original Equipment Slim Line. Its design focuses on ergonomics where a minimalist, fast handling form factor is a priority.

That form factor when compared to the CTR’s is an open triangle, for a more compact top to bottom profile.

While slightly heavier than the CTR, the MOE SL absolutely feels less bulky. It’s like a high speed, low drag refinement.

The SL features an enhanced cheek weld as far as slim line stocks go

With that said, compared to the CTR it also features an enhanced and therefore more comfortable cheek weld. Comfort and minimalism don’t normally go hand in hand, but this also extends to the MOE SL’s butt pad – as we’ll see in the following section.

The SL is the first Magpul stock I’ve bought which features their new two part packaging – this is the full cover sleeve
The inner box with new branding

2.0 Features

2.1 Sling Organisation

The SL features two 1.25” sling slots and an integrated, ambidextrous, steel QD swivel adaptor.

Bear in mind that the latter is not rotation limited.

2.2 Butt Pad

Flat, angled and with a pronounced rollover toe, the SL’s butt pad is designed for varied placement at the shoulder – including when wearing body armour.

The rollover toe provides a smooth, snag free mount and solid ready position index when presenting from low.

The pad is rubberised and textured. It’s also removable, to allow the use of an enhanced butt pad, which adds to the stock’s length of pull (LOP) when fully collapsed.

2.3 Lock Up

Lack of a separate CTR-like locking mechanism may make some users shudder. Doesn’t the stock wobble?


The SL’s anti-wobble feature works through spring pressure and is highly effective. Two internal leaf springs (coated to prevent superficial damage to the buffer tube) hold the stock solidly – perhaps too solidly…

One of the SL’s two leaf springs, which keep the stock wobble-free

The downside is that when adjusting the stock its travel can be hard going, because the leaf springs hold the assembly really tight to the buffer tube. This stiffness is apparently remedied in the storage version – the SL-S, but it’s worth noting here with the SL.

2.4 Adjustment

As there’s no separate locking mechanism with the SL (as opposed to the CTR), adjustment control is provided solely by the obvious lever.

A bifurcated structure, it’s accessible to the user on both sides of the stock and is protected from snagging and accidental release by a hefty bulwark – the SL’s lower edge. Not that the stock is going to just slide, anyway – because the leaf springs are so tight. Adjusting it has to be really deliberate.

With the lever fully depressed, a useful portion of the locking mechanism is exposed. By inserting an appropriate fulcrum into the hole that’s revealed, the stock’s lock pin can be pulled fully proud of the buffer tube’s end stop. Thus, the stock is installed or completely removed. It’s a hell of a lot easier than adding or removing the CTR.

Also note the angled leading edge, fore of the mech. It’s cut away to accommodate sling attachment points like the Magpul ASAP, when the stock is fully collapsed.

3.0 Comparison

In general, the CTR is a great stock to use in comparison because it’s so commonly used and well known. It’s also apt to compare the MOE SL to the CTR in this review, because the MOE SL is the CTR’s successor.

Clockwise from top left: SL, CTR, SL-K

Within the comparison the MOE SL-K (REVIEW) also plays a role. Like the CTR I’ve used it extensively and it’s also part of Magpul’s post-legacy range of stocks.

3.1 Form Factor

The main difference in form factor is that the SL and SL-K are open triangles. The CTR, on the other hand, is a closed triangle.

Despite the SL and CTR being the same height, the SL’s open triangle design gives it a more compact top to bottom profile – as mentioned at the start of the article. This makes it feel smaller and more agile than the CTR.

Top to bottom: CTR, SL, SL-K

3.2 Butt Pad

The SL’s butt pad is a completely different shape to the CTR’s. The latter’s is curved in such a way to comfortably fit in the user’s shoulder pocket – and it does an excellent job of that.

The design of the SL, on the other hand, acknowledges that ballistic plates are now widely worn and that a stock’s butt needs to fit in slightly different places depending on an individual’s body armour fit and adjustment. With that said, the butt also has to work without the use of plates – so it’s more of a multi role shape.

Despite its reduced footprint, the SL-K’s butt is similar to the SL’s design. However, it’s meant to avoid plates entirely by resting on the user up high. For this reason it exhibits a flatter face and much shorter toe. Both the SL and SL-K feature a rolled toe, however – a comfortable index point for the low ready posture.

The SL is slightly longer than the CTR; the SL-K obviously much shorter than both.

3.3 Cheek Weld

Compared with the CTR, the cheek weld of the SL and SL-K is more pronounced. It’s not a huge shelf like the Magpul ACS or LMT/B5 SOPMOD stock, but there’s enough to change the feel for the better. It’s just the right balance, aiming squarely between overt and minimalist.

3.4 Specs

LENGTH (in)7.206.906.50
WEIGHT (oz)9.68.807.90
Table of manufacturer’s specifications

4.0 Conclusion

I wrote an article in May 2019 about the rise of the SL and SL-K in USSOF reference pics. The SL has also been seen in a fairly recent Level Peaks/C2R photo shoot, with an L119A2 that’s been widely accepted as legit.

Crop of the Level Peaks/C2R photo shoot L119A2, with Magpul MOE SL stock

It’s not surprising it’s even penetrated as far as UKSF because while the SL is the CTR’s successor, it’s not a particularly new stock. It is undoubtedly modern, however, and shows this in its open triangle form factor and smartly designed butt pad.

I don’t think we’re at the point yet where an SL can look right on any build, however – it’s not ubiquitous enough for that. On the other hand, the CTR can be added to anything that’s not totally retro and fit right in. The SL? It’s a great looking stock, but for now a bit more thought has to be put into its aesthetic suitability.

As far as function goes, I’d defy anyone to use the SL for a while and not consider it at least as excellent as the CTR. I actually prefer the SL and it’s going on my next build.

Follow The Reptile House Blog on Facebook and Instagram