A week ago I took delivery of a new Sumatra Carbine in .20 calibre and I feel sure that many members of this forum will be interested to learn more about this Korean pcp six-shot repeater.
I imported the Sumatra direct from a dealership in the USA – Mac1 Airgun Distributors –whose owner, Tim McMurray, has extensive experience of preparing, modifying and tuning Korean air rifles (as well as other makes including the AirForce Talon). Mac1 turned out to be one of the few dealerships I came across willing to ship products to South Africa and willing to do so via US Mail. I will say more about Mac1 later, but first let me introduce the Sumatra Carbine…
Maker: Eunjin Industrial Co. of South Korea
Model: Sumatra Carbine 2500
Length: 35 inches
Barrel length: 16 inches
Weight: 6.6 pounds (un-scoped)
Action: Lever action, six-shot repeater
Power output: variable up to 50 fpe (approx.)
Accessories: Filler probe and spare 6-shot magazine supplied as standard.
The Sumatra Carbine is superficially very similar in appearance to the Career 707 Mk2 Carbine which I bought new about eight years ago. Visually it’s a cross between an over-and-under shotgun and a lever-action Winchester Western rifle, with twin air cylinders stacked vertically below the barrel. You either love the look or hate it. Me – I love it.
The build quality appears to be very good, with pleasing attention to detail evident in the bluing of barrel and cylinders, the chequering on the stock and fore-end, the finish of the machining and die-casting and the fit of wood to metal. Of particular note are the die-cast, silvered panels of the receiver depicting a hunting scene complete with fowls and hunting dogs, with a lake as a back-drop.
The barrel is threaded to take a silencer which is fortunate as the bark of a Sumatra on full power seems to me louder than that of a rimfire and definitely needs taming. It comes with a thread protector fitted as standard. The thread size is much smaller than the more common ½ inch UNF.
The gun has open sights as well as an 11mm dovetailed rail for mounting a scope. I found that with the high-combed stock as supplied to the US market, the open sights were unusable and could really be dispensed with altogether– I simply couldn’t get my line of sight down low enough to make them work. This is my first (minor) criticism of the Sumatra.
The six-shot rotary magazine is tiny and a joy to behold and use – there are no moving parts, no spring to play up – you just insert six pellets, skirts down, and slide the mag into its slot in the receiver (the cocking lever must be in the down position to do this). It’s so simple. Retracting the lever cocks the action, and puts a pellet in the breach. The under-lever design means that the action can be cycled rapidly permitting a fast follow-up shot should you need one. The mag is made of translucent plastic with a metal backing plate and you can see how many pellets you have left to shoot. For use in the field, particularly during night time lamping, you would need to count your shots or put up with an irritating ‘dry-fire’ every seventh shot (just at the moment when you have the rabbit’s head in your cross-hairs)!
On the underside of the receiver just forward of the cocking lever is the power adjustment wheel with 13 pre-set adjustment positions representing one full turn of the wheel. For convenience, a black dot on the rim of the wheel marks ‘low’ power, blue is for medium and red is for high power. Although the gun is unregulated, by adjusting the power wheel to increase power after several shots, to compensate for lower air pressure in the cylinder, you can achieve very good shot-to-shot consistency in terms of fps. This has to be precisely calibrated using a chronograph: something Mac1 did for me for a small additional charge.
Forward of the power adjustment wheel, neatly recessed into the fore-end, is a built-in air pressure gauge calibrated in kilos per square centimetre. It doesn’t really matter what the units of measure are: you can use it to tell you when to turn up the power wheel one notch or when to top up with air – very useful.
The Sumatra has a two piece ambidextrous stock with neat chequering. On an air rifle of this quality I would have liked to see a piece of walnut with attractive figuring. Instead the wood has a fine, even grain similar to stained beech – nice enough but rather bland.
Filling the gun with air is straightforward; there is a quick-fill aperture at the end of the lower air cylinder and the probe simply pushes into it. I use a Hill Mk2 hand pump with optional Dry-pack (an excellent piece of kit) and I found charging the rifle up to the recommended pressure of 3,000 psi to be no big deal – even from empty. In normal use the quick-fill valve is protected by a push-on dust cover.
To sight-in the rifle I fitted a Burris Fullfield 2 riflescope. This is a centre-fire rated optic with parallax set at 100 yards (it was previously fitted to my .223). It worked well enough but the usable range of magnification was limited to about 6 x when shooting at 35 yards. Normally, for a high powered hunting air rifle I would choose to zero at 50 yards but I was zeroing in my garden and I was keen to see some results. My chosen method was to use (19mm) circular self-adhesive labels, available at any stationery store, stuck on to a sheet of cardboard (actually, a wine box) placed in front of a solid back-stop. I chose light colour labels to provide contrast with the cross-hairs of the scope.
It was fortunate that the barrel of the Sumatra has the same size thread as that on my Career so I was able to use the silencer from the Career. This was custom made by Joe Young, a UK-based airgunsmith, to tame the muzzle blast of a Career on full power – and it does an excellent job on the Sumatra too.
After initial zeroing on a separate cardboard box, with the scope on 6 x magnification and using Crosman Accupells as ammo, I fired 3 consecutive shots at six labels to see what groups I could achieve. Shooting was from a standing position off crossed sticks with my back braced against a wall of my house.
I was pleased to see that apart from a couple of ‘fliers’ all shots were on the patches. My best effort – shown in the accompanying photo – resulted in 2 pellets in virtually the same hole with the 3rd close by. I’m not into measuring the size of groups but you can see that this 3-shot group is completely covered by a 10 Cent (SA) coin.
The trigger on the Sumatra is an adjustable 2-stage unit. The first stage is fairly slack, which I like, and the second stage let-off is crisp and light enough at a pull-weight of approx. 2 ½ pounds. Further lightening of the pull-weight is not advisable – it is not a ‘match’ trigger.
I’m looking forward to trying out the gun in the field next weekend on a local farm where the unwitting participation of a guinea fowl or two could make for a satisfying outing. There is however one minor drawback regarding use of the air rifle in the field – it has no proper provision for fitting a rifle sling. It’s possible to fit QD swivel studs to the wood of the butt and the fore end but in my opinion the studs would be too close together. What’s needed is an adapter to enable a sling swivel to be fitted to the lower air cylinder. Given the large number of talented gunsmiths on the air-gunning scene someone, somewhere may have already made one.
So what’s the verdict on the Sumatra carbine so far? To summarise my initial impressions I would say that this Korean thoroughbred shows plenty of Eastern promise.
I will round off this review with a comment on Mac1 Airgun Distributors. This is a dealership that caters to the needs of the air rifle enthusiast: Tim lightens the trigger pull-weight on the Sumatra to about 2 ½ pounds and replaces the barrel-to-receiver seal (a recognised point of weakness) with a better quality item. He will undertake further work such as calibrating power wheel settings to maximise shot-to-shot consistency at additional cost. Prices for airguns and accessories are reasonable, as are shipping charges. A big plus for would-be customers living outside the USA is that Mac1 accepts international orders and will ship via US Mail – a massive cost saving passed on to customers when compared with shipping charges made by dealers using international courier firms. Lastly, my order was securely double packed with the airgun in its own carton inside a larger carton, thus ensuring that everything reached me in excellent order. I would not hesitate to buy from Mac1 again should I discover a pressing need to add another air rifle to my small collection.
Mac1 web-site: www.mac1airgun.com
Hill Pumps website: www.airriflepump.com