Posts Tagged ‘gas piston’

The Umarex Octane looks a bit unusual but feels great in the hand.

The Umarex Octane looks a bit unusual but feels great in the hand.

Over a decade ago, when I was just starting to write about adult precision airguns, a guru in the field told me a thing: “If you want a really sweet shooting springer, you want to get as close as you can to one pound of gun weight (including scope) for each foot-pound of energy that the gun generates at the muzzle.”

He was offering this as an explanation for why the humble Weihrauch HW30 is so enjoyable to shoot and why it is such a tackdriver for its power. And, over the years, his statement has pretty much proven to be true. Hold that thought, we’ll get back to it in a little while.

Recently, I had the opportunity to shoot the Umarex Octane in .22 caliber.  It stretches just a half inch over four feet long, and tips the scales at 10 pounds, four ounces with the 3-9 x 40 adjustable-objective scope that comes with it mounted. The Octane incorporates both a gas piston – the ReAxis Reverse-Axis Gas Piston – and the SilencAir noise dampener.

The matte black polymer stock is ambidextrous.

The matte black polymer stock is ambidextrous.

At the extreme aft end of the Octane is a soft rubber butt pad. The entire stock, including trigger guard, is molded from a matte black polymer. The ambidextrous all-weather stock is a thumbhole design, but there is also a semi-circular notch at the top of the pistol grip where the shooter can rest his or her thumb if desired. The pistol grip has some molded indentations for improved grip, and forward of that, you’ll find the trigger guard surrounds a black metal trigger that is adjustable for first-stage travel and a lever-type safety.

The SilencAir system reduces the report and provides a mount for the front sight.

The SilencAir system reduces the report and provides a mount for the front sight.

Forward of that, there is molded-in checkering on either side of the forestock and a slot underneath the forestock to accommodate the cocking linkage. Beyond the end of the forestock is the 19.5-inch barrel, at the end of which can be found the SilencAir, a five-chamber noise dampener which also serves as a mount for the red fiber optic front sight. Moving back along the barrel, you’ll find a micro-adjustable green fiber optic rear sight mounted on top of breech block.

The Octane comes with a 3-9 x 40 adjustable-objective scope.

The Octane comes with a 3-9 x 40 adjustable-objective scope.

Moving back again, a custom metal Pictatinny mounting rail is fitted to the top of the receiver, where it provides a secure mount for the scope that comes with the Octane.

To ready the Octane for shooting, grab the SilencAir at the end of the barrel and pull it down and back until it latches. This requires about 42 pounds of effort and is very smooth and noiseless, as is typical of gas-piston systems. Slide a pellet into the breech end of the barrel and return the barrel to its original position.

Now here is where things get interesting. As you take aim and flick off the safety, you immediately notice that the lever-type automatic safety works exactly the opposite way of the lever-type safety in many other airguns. To turn the safety off and ready the Octane for firing, you pull the safety lever toward the trigger. It took me a minute or two to become accustomed to this, but it works fine, and after a while I took no notice of it. Squeeze the trigger, and a 1 lb. 13.3 oz., the first stage comes out of the trigger. On the sample that I tested at six pounds even, the second stage trips, and the shot goes downrange. This is heavier than the factory-specified 3.5 lbs., but I did not find it annoying.

Umarex .22 Octane 006

Even more interesting, the Octane is a hammer. It launched 14.3 grain Crosman Premier pellets at an average velocity of 838 fps for a very healthy 22.3 foot-pounds of energy.  This is due in large part to the ReAxis gas piston. Its design reverses the conventional gas-piston design so that more weight is driving the piston down the compression tube. The result is more power.

In addition, because of the SilencAir, the downrange report is reduced. This is a powerful gun, so it is not dead quiet by any means, but it is quieter than it would be otherwise.

And now we get back to that business about one pound of gun weight per foot pound of energy. The Octane obviously violates that rule with more than two foot-pounds of energy for every pound of gun weight. In addition, I am admittedly not the world’s greatest spring-piston air rifle shooter. I found that I could occasionally achieve dime-sized groups with the Octane at 20 yards with Crosman .22 Premiers but it was far more typical for my groups to spread out to the diameter of a quarter at 20 yards. Perhaps a more gifted springer shooter could do better, but I couldn’t.

The Octane is not the gun that I would pick for doing head shots on squirrels at 50 yards, but for an air rifle to deal with the woodchuck in the garden at 50 feet or the raccoon that has been molesting the garbage cans, it would be among my top choices. (And with the gas piston, you can leave cocked all day without fear of damaging the spring, because there isn’t any!)

I genuinely enjoyed shooting the Octane, and I think any airgunner who wants to hunt or control pests at short to medium range will enjoy it too.

Til next time, aim true and shoot straight.

–          Jock Elliott