SMK’s CO2 powered rifles - the QB78 Deluxe, XS78 and XS79 review | Rifles Reviews

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SMK’s CO2 powered rifles - the QB78 Deluxe, XS78 and XS79

By: Mark Camoccio

Mark Camoccio checks out three of SMK’s CO2 powered rifles – the QB78 Deluxe, XS78 and XS79

Sportsmarketing (SMK), based in Colchester, import an enormous selection of air rifles and accessories, offering shooters a wide choice of options.

My test models here are three of their ‘Supergrade’ rifles all based around the same robust action. They all utilize carbon dioxide gas (CO2) as the power source, which should mean maximum fun for minimum input. It should also be pointed out that something of a cult following exists for these rifles, largely the result of that simple yet streamlined action, affording the QB78 and XS78 models at least, the appearance and uncluttered lines of a cartridge ammo stalking rifle. With a burgeoning after-market in spares, specialist modifications and tune-ups, all dedicated to these CO2 favourites, their future is assured. So let’s take a closer look and see what all the fuss is about.

CO2 as a power source can be a little unstable, so velocity and energy can vary depending upon ambient temperature. Given that all three rifles on test are beginners models, their modest power output and any slight fluctuations, will probably go un-noticed, so as such, is largely irrelevant. Despite their asking prices - placing these models strictly in the budget category - they have a solid feel and a level of finish which is bound to impress. So let’s look at the first one.

The XS79

The XS79 model takes the large bulk fill 88gramme CO2 cylinder, which, once screwed into place, is good for 180-200 shots. Of course the cost of these disposable cylinders needs to be factored in (at around £6.99 a throw), but they do allow fairly prolonged shooting sessions to take place before a refill is needed. The downside of this design is that, because the forend is curtailed, the CO2 cylinder itself becomes the forend, meaning the leading hand has to grip a cold cylinder instead of the comfort of woodwork.

The hardwood beech stock fitted to this model exhibits some very attractive grain pattern, whilst the thick lacquered finish and rubber butt pad all add to the overall impression.

Conventional iron/open sights come fitted to this XS79, although they are rather basic and awkward to adjust. Most owners, I suspect, will be fitting glassware of some sort fairly early on, and this is made easy by the provision of extended scope rails, which run the full length of the breech block.

Removing and replacing the 88gramme CO2 capsule is made easy and safer by the addition of a knurled adapter collar, which allows any unused gas to escape safely via the vent hole.

The XS78 and QB78 Deluxe

Both these models follow the same layout, and require two 12gramme CO2 ‘bulbs’ to be inserted back to back inside the cylinder. Once the knurled end cap, just forward of the forend, is screwed into place, the bulbs are pierced and CO2 is released as required. This arrangement provides around 40 shots before the power drops, and with the 12gramme bulbs costing around 75p each, again, the extra cost of shooting needs to be borne in mind.

CO2 basically offers its own contained power unit, so the action can be free from springs and pistons, purely requiring a simple internal valve to meter the CO2. This allows for much lighter designs, and with these models tipping the scales between 5.28 and 5.75lbs, any newcomer should find them wholly manageable.

The QB78 Deluxe model offers a gold anodised bolt handle and trigger blade, which adds a touch of class to an already attractive rifle. Add in a properly adjustable set of fibre optic open sights, and the extra £20 suddenly seems a bargain.

Bolt and trigger

All three rifles incorporate the same barrel over cylinder arrangement, and all three include a bolt mechanism, which is very easy to pull back, then slightly irritating to push forward and lock down. I have been reliably informed that this should improve with use, but the bolt is definitely over-sprung and a little stiff, which just takes the edge off an otherwise enjoyable experience. As for that plastic barrel support (fitted to all three models), this could be removed by the more adventurous owner, restoring true floating barrel status at a stroke.

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Truly appreciated

I believe all these niggles are the subject of the XS78/XS79 Appreciation Society (I kid you not), so someone out there will be tuning, modifying and re-jigging these idiosyncrasies as we speak. The bolt and single stage trigger would be a good place to start, yet consider those RRP’s again, and the slightly creepy trigger is both perfectly usable, and even attractive, given its curved shape within a cast guard.

Being CO2 powered, all these rifles are recoilless, and with accuracy of around 3/4 inch at 20yds (achieved using the recommended .22 Milbro Select), close range hunting is also a possibility.

CO2? It’s a gas…

Ok; I’ll admit, I’m normally no great fan of CO2, yet legions of shooters are. All I can say is I certainly warmed to these models whilst they were in my care, representing as they do, some of the best examples out there.

Technical Specifications
Model	QB78 Deluxe / XS78 / XS79
Manufacturer	SMK / SMK / SMK
Type	Single shot/bolt action / Same / Same
Calibre	.22 only / .177 or .22 / .177 or .22
Weight	5.75lbs / 5.28lbs / 5.28lbs
Overall Length	40inches / 40inches / 40inches
Barrel Length	21.5inches / 21.5inches / 21.5inches
Stock	Beech sporter / Same / Same
Power Source	2x 12g co2 capsule / Same / 88g cylinder
Shot Count	40 shots (within 25fps) / 40 / 180
Velocity	Average 523fps / 523fps / 540fps
Shot to variation	25fps / 25fps / 30fps
Energy	9ft/lbs average on test / 9ft/lbs / 9.6ft/lbs
Trigger	single stage-3-way adj / same / same
RRP	£129.95 / £109.95 / £109.95
Uses	Beginners rifles/close range hunting

All Prices Are Guides Due to the Changes in US & European Exchange Rates

This review has 7 comments

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User Comments

I have an QB78 .177 that I bought several years ago.

Firstly, the reason the bolt is harder to push forwards (to the firing position), is because unlike most bolt actions, it cocks when being closed to the firing position.
so until the bolt is locked forwards, the gun is safe.

On mine the bolt was stiff (both directions), and the mechanism was generally rough around the edges.

I decided to strip it down, and then semi polished some parts and smoothed the burrs of other parts...
And I removed the filter from the co2 valve (its not needed, and I believe later guns dont have them)

Mine QB78 is now very smooth and predicable, and is great fun.

With a bit of tuning, and modification or replacement of parts, they can easily get to the 12lb-ft. I am going to tune mine to around 11~11.5lbft.

From the info I have read the .177 models will just about get to 12lb-ft, but the .22 can exceed it very easily.

All in all, I think they are a good, underestimated gun that you can tune have some fun with.

Strongly recommended.

Comment by: K Posted on: 09 Jan 2011 at 03:13 PM
ive just got the smk xs78 put it up two 12lb as they are set at 9lb when i had mine on the 17/ 5 /11 got 4x4/9 40 scops fitted silencer as well and put it to the test this saterday and it was great to see this gun acted like a pre charge gun i got 40 shots at high power then after that the co2s died out but the gun is very good at the price of £100 pounds my day state was £800 pounds with bottle scops and silencer and the smk xs78 is just as powerful .lovely gun in lools and power.

Comment by: MICHAEL DONNELLY Posted on: 13 Nov 2011 at 01:45 AM
I bought a SMK 79 I didn't expect too much given the price but I was suprised at how accurate it was. I shoot up to twenty metres and use my gun to hunt.
I can hit three quarter of an inch groups at twenty metres easily and time and time again. The power is advertised at around ten foot/LB which is ok for shooting up to twenty metres. The gun it self was very well made in comparison to my old Crosman rabbit stopper , No plastic bolt bolt assembly , heavier metal work and it came with proper scope mounts which took my one piece mount.
I have owned Wierauchs, BSA,Webley and others including a PCP over the years . I would say this rifle is as accurate as any of the guns I've owned . My only criticism would be the stock cheek piece is very low . I may get my tuned but it seems perfectly ok as it is. Over all I would be very confident of hitting a kill zone on small vermin again and again with this rifle. Ive owned lots of more powerful rifles(spingers) in the past but I have to say I've never had quite such an accurate rifle which I'd be confident to hit on the bulls eye every time.
Ive fitted a SMK silencer and it is very quiet.
I would recommend this rifle to any one.

Comment by: Martin ROGERS Posted on: 16 Jan 2012 at 03:53 PM
For pound per pound its No1, an entry level with out a doubt. The basic workings of this gun also make it a good tuning project. If you are interested in tuning your 78/79 email me at highviss @googlemail.com and i would be happy to provide you with info on this.

Comment by: Tony Posted on: 27 Feb 2012 at 08:48 AM
For the money you cannot complain. The QB78 .22 cal. is the best one. Fit the Terry Robb tune up kit and make sure you clean out the gun properly as swarf is a major problem and causes valve malfunction. Make certain you have a chrono because using lighter pellets could put you over the limit and carry you into the long arms of the law. On warmer days you will have a sweet handling bang on the limit 12ft.lbs rifle.

Comment by: Pete John Posted on: 10 May 2012 at 05:26 PM
just recently i have sold my smk 19 .22 and im wanting the th78d in .22 have you guys got any info of the gun if its a good buy or watevea realy would like opinions and power info thanks .

Comment by: steve hayes Posted on: 18 May 2012 at 10:12 PM
Th78 is a Qb78 with a thumbhole stock which makes it more money for basically the same gun. Look at the TR Robb (gunsmith of Southend) website. He has lots of stuff for this gun. Buy a Qb78 and the Robb tuning kit and have a full power gun for the same money as you will pay for a medium power Th78.

Comment by: pete john Posted on: 20 May 2012 at 11:37 AM

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