Gamo Rocket IGT breakbarrel .177 air rifle: Part 2
by B.B. Pelletier
Let’s look at the power and velocity of the Gamo Rocket IGT .177 breakbarrel air rifle. You learned in Part 1 that the numbers printed on the box and gun were in disagreement with the Gamo USA website and Pyramyd Air’s site, but it turns out that 1,300 fps is the correct velocity according to an email Edith received from Gamo’s vice president of sales. Well, Edith spotted yet a third velocity claim — this time on the end flap of the box. A sticker listed the velocity as 1,000 f.p.s., with no further explanation. We’ll clear all of this up and find out just how fast this rifle really does shoot.
I remarked in Part 1 that the cocking effort of the rifle seemed low for a gas spring, which is what IGT (Inert Gas Technology) means. My guess was the rifle cocked at between 30 and 35 lbs. of effort, which is a good 10 pounds less than other gas springs that generate similar power. My bathroom scale confirmed that the test rifle cocks with just 33 lbs. of force, making it easier than most gas springs. The piston stroke is quite long, which is how they manage to generate all that power from such an easy-cocking powerplant. I applaud Gamo for using the physics of the gas spring in this creative way.
I also remarked that the new Gamo Smooth Action Trigger or SAT, as they call it, is a large leap forward from any Gamo trigger I have ever tested. It’s adjustable via a hard-to-access Phillips screw located behind the trigger blade; and when I attempted to adjust it, I discovered that it was set by the factory to the best position.
Screwing the adjustment screw clockwise reduces the stage-two pull length and counterclockwise does the reverse. The screw was in as far as it would go, but I did unscrew it a full turn and verified that it does increase the second-stage pull length.
The trigger released at 4 lbs., 4 oz. with good consistency. The first stage is very light (just one ounce) and stops positively at stage two. This is the kind of sporting trigger that will please many shooters, and I’m so glad to be testing it.
The last comment on the trigger is that Gamo has made the safety entirely manual. The blade is in an usual (for Gamo) place, but it doesn’t go on when the rifle is cocked. I see that as a positive step toward customer satisfaction. Gamo has somebody who knows how to design airgun triggers.
And now to the principal business of the day. I tested the Rocket IGT with four pellets — two made of lead and two that are lead-free. The first pellet tested was the JSB Exact 10.34-grain dome — a heavy pellet for a .177. With a gas spring, there’s no coiled steel mainspring to worry about, so the question of whether this heavy pellet is suited to a spring-piston powerplant is moot.
The JSB Exact pellet got an average velocity of 822 f.p.s., which was below the estimate of 900 f.p.s. I made in Part 1. The velocity spread went from a low of 816 to a high of 828, so a 12 foot-second spread over 10 shots. That’s very consistent. At the average velocity and using weight of 10.34 grains, this pellet generates 15.52 foot-pounds of muzzle energy.
Next up was the H&N Baracuda Green — the new lead-free pellet that’s surprising us with its accuracy. And that’s why I tested it here — because I intend to try it out in the accuracy test, as well. They averaged 1100 f.p.s. on the nose, and the range went from a low of 1092 to a high of 1105 f.p.s. So the spread was a tight 13 f.p.s. At the average velocity, this 6.48-grain pellet averaged 17.41 foot-pounds. That’s good power for this rifle; and if these are accurate at 25 yards, they’ll be a good hunting pellet for rabbits, squirrels and similar game.
Following the Greens, I tried Gamo’s PBA Platinum pellet, a 4.7-grain lead-free dome that they pack with the rifle. This is the pellet they say will go 1,300 f.p.s. (although Gamo’s website still says 1,250 fps). In the test rifle, this pellet averaged 1,229 f.p.s., but the string was large. It ranged from a low of 1,214 f.p.s. to a high of 1,242 f.p.s. The spread was 28 f.p.s. While that’s not terrible, it’s noticeably greater than all other pellets that were tested. At the average velocity, this pellet generates 15.77 foot-pounds at the muzzle.
The rifle comes pretty close to the 1,250 f.p.s. claim still listed on Gamo’s site (as we write this) — but not the 1,300 fps they claim on the box and rifle.
The last pellet tested was the venerable RWS Hobby. This 7-grain lead pellet is often the fastest of its type. In the Rocket, they averaged 1,004 f.p.s. with a spread from 996 to 1,013 f.p.s. The spread was 17 f.p.s., and this pellet generated 15.67 foot-pounds of energy at the muzzle. Once again, the Gamo rifle met its advertised velocity with lead pellets.
Observations thus far
Gamo met the advertised velocity for lead pellets but was below the advertised velocity for their Platinum PBA pellets. Their Inert Gas Technology gas spring is easy to cock and doesn’t vibrate much when fired. And their new Smooth Action Trigger is performing just as nice on this rifle as the mockup in the Gamo booth did at the 2012 Shot Show.
I think you can sense my approval of this air rifle so far. It’s completely modern and nothing like the guns I usually favor, but it cocks easily, it generates the power it’s supposed to, is lightweight and has a fine sporting trigger. If it turns out to be accurate as well, I think Gamo has a fine new rifle in their lineup.