KJ Works MK 1


The replica I’ll be talking about in this review is the KJ Works MK 1, a replica of the Ruger MK I Target pistol. In many ways, this represents the shallow end of the replica gene pool. It’s non-blowback and of mainly plastic construction. It’s also very cheap – it’s available in most parts of the world for around the equivalent of €35. For these reasons, many people dismiss this as being a toy rather than a serious replica, but I think that’s probably a mistake. Visually and in terms of handling, it’s a wonderful copy of the firearm it replicates and it’s more powerful than you might expect for a simple, gas powered replica.  So, let’s put aside preconceptions and take a look at the KJ Works MK 1.

The Ruger Standard/MK I

Bill Ruger had always been interested in firearms. While at college, he produced a design for a light machine gun. After a period working as a gun designer for Springfield Armory, he left and joined the Auto Ordnance Corporation in Bridgeport, Connecticut where he worked on an innovative design for a new machine gun. He completed the design in 1945, just as World War Two was ending and US Army interest in a new machine gun evaporated. Undaunted, Ruger began work on a new semi-automatic pistol. Ruger intended to produce a design for a .22” target pistol that would be inexpensive, reliable and rugged. Inspired by a Japanese Nambu pistol which he purchased from a returning US Marine, he completed the design in early 1946. The only problem was, he didn’t have any money to manufacture or market the new pistol. At that point, Ruger met Alex Sturm, a graduate of Yale Art School with a passion for firearms. The wealthy Sturm family agreed to lend the two men $50,000 and they started the Sturm, Ruger & Company, Inc in 1946. In 1949 the company started marketing a single product: The Ruger Standard pistol.

The Japanese Nambu Pistol. Ugly old thing, isn’t it?

Few people in the industry were hopeful about the new company. After World war Two, America was awash with cheap military surplus guns. Would people really be willing to buy a small caliber target pistol from an unknown new company? In the event, the answer was an overwhelming ‘Yes!” The Ruger pistol was so successful that by the 1980s, when established firearms manufacturers like Colt and Winchester were facing bankruptcy, Ruger remained profitable and today is the fourth largest firearms manufacturer in the US. Of course, the company now makes far more than just target pistols, but it was the success of the original pistol that helped to establish the company. So, just what was so special about the Ruger Standard?

The original Ruger Standard. Now, that’s more like it. The Standard may be inspired by the Nambu, but it’s just a much more elegant looking pistol.

First of all, the Ruger looked different to most rimfire target pistols –  that distinctive angled grip echoes the Luger pistol (due to the similarity in names, some people have assumed that there is some relationship, but the Ruger is clearly modelled on the Japanese Nambu, not the Luger). The lack of a moving slide also makes the Ruger look distinctive – just like the Nambu, it uses a bolt at the upper rear of the receiver. Most importantly, it felt good in the hand and, like all the best target shooters, it was a natural pointer. It also turned out to be simple, reliable, accurate and easy to maintain. And let’s not forget that the Ruger Standard was also very cheap compared to other contemporary semi-auto pistols. The first models sold for the very competitive price of $37.50, not much more than half the price of, for example, a contemporary Colt Woodsman.

Ruger MK I Target with heavier 5.5” Bull Barrel. One of the most popular models up to the early 1980s.

The Ruger Standard remained in production until 1981, as did the first variant, the MK I Target, introduced in 1950. This was essentially the same as the Standard, with the addition of an adjustable trigger, an adjustable rear sight, an undercut front sight and a 6.8” tapered barrel. However, the most popular of the early versions of this pistol was the MK I Target with a heavier 5.5” Bull Barrel. The MK Target series went on to include the MK II (in 1982), the MK III (in 2004) and the MK IV (in 2016). By 2000, Ruger were offering 18 versions of this pistol in different finishes and barrel lengths and to date over 2 million have been sold, making it one of the most popular semi-auto .22” pistols ever made.

The KJ Works MK 1


This isn’t a licensed replica so you won’t find any Ruger markings here or any mention of the word “Ruger” on the box, packaging or on the replica itself. A full-size, drop-out magazine holds the gas and up to 17 BBs. The magazine latch is in the heel of the grip. A sliding manual safety is provided on the left side of the frame. When the safety is engaged, the trigger cannot be pulled. Adjustable hop-up is provided and adjusted using a 1mm hex key (not provided) via a small hole in the top of the receiver. The original version of this replica had a plastic hop-up chamber but later versions (including the version tested) have a metal hop-up chamber which is claimed to improve accuracy. If you have a version with the plastic hop-up, you can buy the metal hop-up casing as an upgrade from KJW.

Packaging and presentation (2/5)

This replica comes in a moulded polystyrene base with a colour printed card lid. Inside you’ll find the pistol, one magazine, a small box of KJW BBs, a user manual and a colour brochure for other KJW products. The User Manual is better than some, but it somehow manages not to mention how to adjust the rear sight or the hop-up (the illustrations in the manual actually show a Ruger Standard with a fixed rear sight). One thing that’s notably missing from the box is a 1mm hex key to adjust the hop-up.


Visual accuracy 8/10

This a very good visual replica of the Ruger MK I. Dimensionally and in terms of controls and everything else, it’s spot-on. Only the fact that the trigger sits so far forward in the released position gives away the fact that it’s a replica.

This isn’t a licensed replica, so it has no Ruger markings. In fact, mine has no markings at all other than a small KJW logo on the right grip. A nice touch is that, on most replicas, you’ll find that the front part of the barrel has a larger, recessed cut-away, to replicate a 9mm or .45” opening. There’s no need for that here – a 6mm BB is actually slightly larger than the tiny .22” round fired by the Ruger.

Functional accuracy 11/15

The only controls on the Ruger MK I (other than the trigger) are the magazine latch in the heel of the grip and a sliding manual safety on the left side of the frame. There are both accurately modeled in form and function on the KJW MK 1. This isn’t a blowback replica, so it doesn’t have a true single action trigger – the first part of the long trigger pull is used to move the barrel for firing and queue up the next BB for shooting. The bolt is a separate part, but it can’t be moved without disassembly.

Disassembly is, I believe, fairly similar to the original. The magazine must be removed then a tab on the backstrap is levered down and this allows the centre part of the backstrap to hinge up. This is attached to a post which runs through the receiver and bolt, locking both in place. When the post is removed, the receiver, bolt and barrel can be lifted off as one unit. The plastic bolt slides out of the back of the plastic receiver and the brass barrel and metal hop-up casing can also be slid out to the rear. Disassembly and reassembly are more fiddly than on a pistol with a conventional slide, but then you shouldn’t need to disassemble this often as it won’t need the kind of lubrication that a blowback replica does.

Shooting 30/40

Loading the magazine on the MK 1 requires the follower to be held down – it can’t be locked.  Up to 17 BBs are then dropped down just in front of the firing valve. Filling with gas happens without leaks or drama, and despite this being a fairly small magazine, you get more than two full magazines of BBs out of a single fill (I was getting 45 – 48 shots before power started to drop off). The magazine latches positively when it’s inserted, and you then only need to slide the manual safety down to the “Fire” position and you’re ready to shoot.

The first thing you’ll notice is the long, relatively heavy trigger pull. This replica uses a unique (as far as I’m aware and apart from the KJW MK 2 which uses the same system) moving barrel system. All the other replicas I have tried which use a moving barrel involve the barrel moving forwards until it reaches a release point whereupon it snaps back against a spring and hits the front of the firing valve, causing the replica to fire. On this one, the inner brass barrel moves backwards as you pull the trigger, collecting a BB from the magazine and pressing the rear of the barrel against the front of the firing valve. A conventional internal hammer then strikes the back of the firing valve and the replica shoots. This gives a very long pull and the pistol doesn’t fire until the trigger is back almost touching the frame – you do need to use the ball of your finger on the trigger to get to the release point. It’s not horrible, and it is lighter than some other moving barrel design replicas I have tried, but it can get tiring if you’re shooting for an extended period and it is a challenge to keep the sights on-target during the long pull.

The notch and post sights are clear and easy to read, but they lack white dots or any form of aiming aid which can be a problem if you’re shooting against a dark background. The fact that the rear sight is fully adjustable is a nice touch though on mine, even fully adjusted I could not get the point of aim and the point of impact to coincide.

Accuracy is variable and only acceptable provided you learn to deal with the trigger pull and/or use a rest when shooting. When I first got my KJW MK 1, it grouped at a very respectable 1¼” at 6m. However, when I took it out to re-shoot it for this review, it is producing groups closer to 2” and I have no idea why. Everything works as it should and it was throroughly cleaned, but the groups now just aren’t as tight as they were when I first used it.

Ten shots, 6m, free-standing, 0.3g BBs. Aim point was the centre of the black circle.

At this range and even with the rear sight adjusted as much as possible, mine was hitting around 2” above and 1” to the right of the point of aim even with heavier 0.3g BBs. I did try adjusting the hop-up to drop the point of impact, but on mine at least, this did not have any noticeable effect. A 1mm hex key is required, but the adjustment screw was so stiff that I when I first tried to turn it, the hex key started to rotate inside the soft metal screw. Not very impressive. With a different hex key, I was able to turn the adjustment screw, but I could see no difference in shot placement at 6m.

Early versions of this replica had a plastic hop-up casing. Later versions have a metal casing like this which is claimed to improve accuracy. I have also seen claims that earlier versions had longer mainsprings, which made the trigger pull even heavier. I have no idea if that’s true – mine seems to be a later version, but the trigger pull still felt long and heavy to me.

The KJW MK 1 is moderately loud – it has a sharp crack that’s satisfying but not so loud that it will annoy the neighbours. One of the claimed benefits of the moving barrel system used on this replica is that it is said to improve power. I have read several claims for the power of this replica, ranging from 400 – 500fps. Mine didn’t manage that – in fairly warm (around 28˚C) conditions using 0.2g BBs it consistently recorded between 380 and 400 fps. It was very consistent, generally between 385 and 390 fps with only occasional shots above or below this range. Which is fine  for target shooting, but probably makes this replica too powerful for skirmishing (though I believe that using Duster Gas can reduce power to acceptable skirmishing levels).

When you’re finished shooting, removing the magazine is a two-hand job; the small sprung catch in the heel of the grip needs to be held to the rear and then the magazine can be pulled out. It’s a tight fit and it needs a good grip on the serrations on either side of the bottom of the magazine to get it out. However, this is just as it is on the original, so I can’t fault the KJW MK 1 for that.

I enjoyed shooting the KJW MK 1, despite the long and heavy trigger. Getting good groups was a matter of staying focused on the target throughout the long trigger pull. This replica is very similar to the Marushin Sturm Ruger MK 1 and I know that there is a “Light Trigger Kit” available for that replica which is also claimed to fit this one. The kit provides a set of replacement springs, and I’d certainly be interested to try that kit to see if it did significantly improve the trigger pull. There are also several potential internal improvements which are said to make this replica a more pleasant and accurate shooter – you’ll find a link to an article on some of these at the end of this review.

Quality and reliability 12/15

Other than the hop-up adjustment screw which initially wouldn’t move on mine, I didn’t have any problems with this replica. It loads and shoots without any issues though a couple of occasions, the first shot with a full magazine would shoot two BBs. The only minor irritation is that, when loading the magazine, you have to be careful to release the follower gently, otherwise one or more BBs are likely to be ejected from the top.

Although it’s mainly plastic external construction, everything seems robust and well-made and the mouldings are sharp and clean. I don’t know what sort of plastic is used, but when the replica is assembled, it actually feels like a pistol, not a toy. The internals are relatively simple, so there isn’t much here to break and of course, being plastic, the finish won’t scratch or rub off. Overall, this feels like a higher quality replica than the low price would suggest.

Overall impression 13/15

When I ordered this on-line, I wasn’t sure what to expect. It’s plastic and the quoted weight (which varies from place to place) is generally given as between 600 and 700g (1.3 – 1.6lbs). However, on my scales and with the magazine in place, it is just 546g (1.2lbs). That’s very light indeed and I was afraid that this would feel very toy-like. However, it doesn’t, but I’m not sure why. For example, the Umarex Walther PPQ M2 which you’ll also find reviewed on this site is over 100g heavier than the MK 1, and I complained that the PPQ felt too light. Strangely, this one doesn’t. I found it to have sufficient heft and balance to make a reasonable replica. Go figure.

Overall, this is a simple, well-made replica of a simple, well-made pistol. It looks good, it feels good, it shoots fairly well and it appears to be reliable. What more could you want for the price? Of course I’d like a full blow-back version of the Ruger Mk 1, but that’s not what this is. Cheap isn’t always cheerful but in this case, the KJW MK 1 does usually put a smile on my face.


This isn’t a perfect replica by any means. It lacks blowback, it’s made of plastic and the moving barrel system gives a long and heavy trigger pull. I did try disassembling and oiling and greasing all parts of the trigger and moving barrel assembly. This perhaps made the trigger pull a little smoother, but it was still just as long and heavy. However, it shoots reasonably nicely and with good power and it seems well made and put together. Best of all, it’s a spot-on visual replica of a classic pistol and it inherits all the great handling and pointability for which the original is so famous. It’s a pity it isn’t a licensed replica with the correct markings, but if it was, it would probably sell for twice the price.

If you like replicas of historic pistols (and they don’t get much more classic than the Ruger MK I) then this probably deserves a place in your collection. The good news is that it’s cheap as chips too. There just aren’t many sub-$50 replicas out there which are worth having, but this is one. If you can put up with its idiosyncrasies, or perhaps if you fancy trying your hand at some improvements, then you are probably going to want one of these.

Total score



Long, heavy trigger makes consistent shooting challenging.

All plastic external construction.

No blow-back.


Great visual replica of a classic pistol.

Seems well made and reliable.



Can be upgraded/improved.


The KJW MK 1 is a popular replica to improve. A number of sites provide guidance on improving the trigger pull, power and accuracy, but this one provides a good overall guide to lots of internal modifications (and these also apply to the KJW MK 2):

One thought on “KJ Works MK 1

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