- Eun Jin Sumatra carbine
| The Sumatra Carbine |
A lot of performance in a small package
| or read the article on the rifle || Sumatra |
A powerful lever-action repeater
By Tom Gaylord
exclusively for PyramydAir.com. © Copyright 2003 All Rights Reserved
A carbine is, by definition, a very short rifle. Usually all that's done to create a carbine is to cut down a rifle until it meets the definition. But the Sumatra carbine, while fitting the definition very well, is more than just a smaller version of the rifle; it's a unique airgun in its own right and may even be better than the rifle, especially if you plan to hunt in thick brush.
Compact and powerful, the Sumatra carbine is a great little hunting gun.
Made by Korean air rifle maker Eun Jin, the Sumatra carbine is 36.25" long and weighs about 6 lbs. It has a six-shot revolving cylinder that advances with each cycle of the lever, which also cocks the gun. Many of the features are the same as those found on the rifle, which is also reported on this website, so this review will concentrate on things not covered in that report.
The trigger is a simple single-stage unit that is adjustable to some extent. What adjusts is the sear contact area, so you must proceed cautiously. Turning the Allen screw inward (clockwise) makes the contact area smaller; turning it outward makes it larger and, therefore, safer. I adjusted the test gun to about a five-pound pull, with a fair amount of creep.
The trigger adjustment screw is located to the right of the trigger when the rifle is upside-down. Screw in for less sear contact, out for more. Be sure to leave enough contact surface so the sear doesn't slip and fire the gun unexpectedly.
The rear sight is identical to the one on the Sumatra rifle. It adjusts for windage only.
The front sight adjusts for elevation using the small wheel shown here. It is also the same as the sight found on the rifle.
The carbine comes with the same fine open sights as the rifle. The rear adjusts for windage and the front adjusts for elevation. A scope mount dovetail is attached to the top of the receiver to accept 12mm scope mounts. I used B-Square Lynx steel rings to hold a Leapers six-power compact scope with 40mm objective lens. Sight-in took two shots at 10 feet, and I immediately went to 25 yards with that setting. It only took some small tweaking of the scope knobs to bring the groups where I wanted them at that distance.
A Leapers compact scope suits this carbine well. Though it is short and lightweight, the optics of this scope are crystal clear. Because the carbine doesn't recoil, a scope stop is unnecessary.
I found it very easy to mount the scope and sight in. Notice that I used a simple two-piece mount that has no recoil stop. This rife recoils so little that a recoil stop is unnecessary. It took all of five minutes to mount the scope and sight in.
I would only use one pellet with this air rifle - the Eun Jin heavyweight dome from Pyramyd Air. They average 23.9 grains in .22 caliber and are well formed. They are on the small side of average as far as diameter is concerned, which makes them loose in some airguns but just right in the Sumatra and Sumatra carbine.
Once I located the high-power setting on the power-adjustment wheel, the carbine gave me 10 shots ranging between 920 and 813 f.p.s. Every shot was slower than the one before, so the median became the representative velocity. Taking 866 as that point, the carbine averaged 39.81 foot-pounds for the first 10 shots. That's plenty of power for raccoon-sized game if the accuracy is there - and with this carbine, it is!
Eun Jin pellets (on the right) are the best ones for the carbine. JSB Exacts work well at reduced power levels.
With Eun Jin pellets, I got repeated 25-yard groups in the 0.330" to 0.340" range, center-to-center. They would probably open to about one inch at 50 yards on a perfect day, so the carbine shoots as accurately as the full-length Sumatra rifle, which is rare. Normally a carbine spreads its shots out more than a rifle, but not this one. And, because it is much shorter and faster-handling than the rifle, the carbine is a hunter's dream gun.
This group of five Eun Jin pellets at 25 yards measures 0.331 center to center. No attempt was made to center the group in the bull as several pellets were being tested at the same time.
Five JSB pellets were almost as accurate at 25 yards, but the gun had to be shot several times so the pressure was reduced before this lighter pellet could be shot on high power. It would have gone supersonic otherwise, and that destroys accuracy. Again, no attempt was made to center the group.
JSB Exact pellets gave groups just slightly larger than Eun Jins, but since they weigh only 15.9 grains, they don't generate the same power. Fortunately, they seem to shoot to the same point of aim. After shooting 10 Eun Jins, I used the lower air pressure remaining in the gun to shoot 10 more JSBs. That kept them from going supersonic and ruining accuracy. Therefore, you could use JSB pellets in the Sumatra if you use them in this specialized way, or you could turn the power setting down to low and get a longer string of shots. Power will still be in the high 20 ft.-lb. region, which is well into the magnum class.
Power is adjustable, though I found that the power wheel rotated completely through all the power settings then reverted back to low power if the wheel continued to turn in the same direction. That takes some getting used to because the normal way to adjust a power wheel is from one stop to the other - high to low or vice-versa. Though I spent all my time at the high setting, I expect the low setting to give 1.5 to 2 times the number of shots at a correspondingly lower energy. If you want to shoot JSBs only, this would be a sound way to proceed, giving at least 30-40 good shots on a fill.
The carbine comes with a quick-fill probe that must be attached to some kind of hose to fill the gun. The probe is smaller than every other airgun probe I am familiar with, so it needs to have its own dedicated hose. I filled the gun to 3,000 psi from a scuba tank, but a manual pump would do the job, too. And the carbine is quicker to fill than the rifle because of the reduced air capacity in its shorter reservoir tubes, which are the two big tubes under the barrel.
The power wheel moves continuously in either direction. Use the marks on the wheel to tell where the power is. Red is the highest and green is the lowest.
This is a good-looking air rifle. The stock is Asian walnut and both the butt and the stubby forearm are checkered. Finishing has improved over the years and now seems as good as what is found on the better European rifles. The receiver has bas-relief "engraving," which is actually stamped into a thin metal shell that covers the action. The muzzle is threaded for those who wish to install a legal silencer. Remember that BATF must approve of all silencer transactions and that a $200 tax stamp is required for the purchase of each device.
The Sumatra carbine quick-fill probe slides into the port near the muzzle of the gun. A rotating cover keeps dirt out of the port when the gun is not being filled.
The carbine comes with two six-shot magazines and a quick-fill probe, plus Allen wrenches and an owner's manual. If you are a first-time buyer, it would be best for you to also purchase the rest of the charging device (the clamp that attaches to a scuba tank K valve with the hose to accept the gun's probe) when you buy the gun, so there are no mistakes. Then, you'll be ready to go when you unpack your gun.
Another thing first-time buyers should know about powerful precharged airguns, especially those with short barrels like this Sumatra carbine, is that these airguns are loud - much louder than spring-powered air rifles. This gun is suited to open spaces where noise is not a problem. Even with the power on the lowest setting, this is not an indoor air rifle. That said, the Sumatra carbine is a very nice combination of good power and great accuracy in a small package at a good price. If you want to hunt with an airgun, this is one of the best rifles to use.