Gamo’s Silent Stalker Whisper IGT air rifle: Part 2
by B.B. Pelletier
Okay, this is the week of the Roanoke airgun show. I’ll be on the road from this Wednesday until the following Tuesday, and I’m asking you veteran readers to help the newcomers with their questions. I’ll still read the blog each day, but it’ll be only during a short period in my motel each evening. Edith will be at home and will continue to monitor the blog and the comments and contribute as needed.
Today, we’re going to look at the velocity of the .22-caliber Gamo Silent Stalker Whisper IGT we’re testing. I said “Wow!” a lot in Part 1, so I certainly hope that sentiment carries forward in today’s test.
This rifle has a gas spring; so, although it’s a spring-piston air rifle, it works a little differently from the typical springer that has a mainspring made from coiled steel. A gas spring maintains the full force of the spring all the way through the cocking effort. Or at least that’s how it feels. A coiled steel spring, in contrast, starts out with little resistance and builds to the maximum about three-quarters of the way through the cocking arc, which is coincidentally the place where the leverage is the greatest for a breakbarrel.
Because of the way the gas spring works, it feels harder to cock than it really is. The secret to cocking one, if there is such a thing, is to not go fast. Just pull the barrel down through the cocking arc with a smooth, consistent pull, and it’ll feel as light as it’s going to. The Gamo specs say this rifle cocks with 32 lbs. of force; and when I tested mine on the bathroom scale, it measured 35 lbs. That’s pretty close. I told you in the first report that this piston has a long stroke, which allows the gas pressure to be lower and still generate the higher power they’re claiming. Let’s now see what that power is.
A pellet I pretty much have to test is the 14.3-grain Crosman Premier dome. I say that because I know I’m going to try it during the accuracy test. Gamo rates this rifle at 975 f.p.s. with lead-free pellets, so I estimated before shooting that the Premier would go around 750 f.p.s. That’s just about what you’ll get from a new Beeman R1, which is a very powerful breakbarrel rifle. Let’s see if I’m anywhere close. I made that guess before sending the first shot through the chronograph.
Ten Premiers averaged 685 f.p.s. The spread went from 678 to 690, so only 12 f.p.s. separated the fastest shot from the slowest. That was less velocity than I expected, but it is right in the ballpark of where I wanted the gun to be, for accuracy’s sake. That works out to an average muzzle energy of 14.9 foot-pounds.
The firing sensation is nearly dead calm, unless you hold the rifle tight. It feels like one of the finer custom tunes on a spring gun. The trigger is long and draggy in stage two, and I’ll look into adjusting it, but I’ve worked with this trigger design in the past and don’t think the adjustment changes much. Nice firing behavior, though!
The pellet that should give the claimed velocity is the RWS Hobby. Weighing just 11.9 grains, it’s the lightest pellet that has any chance for accuracy in a rifle of this power. Hobbys averaged 727 f.p.s. from the Silent Stalker Whisper, which gives an average of 13.97 foot-pounds of energy at the muzzle. But the velocity spread went from 714 to 749 f.p.s., for a whopping 35 foot-second difference. That’s pretty large, though I’ve seen bigger spreads shoot very well at 25 yards, which is where I’ll be testing this rifle.
Firing continued to be calm with the Hobbys. Because the power is not as fast as anticipated, I decided that the last pellet I would test would be the 14.3-grain JSB Exact Express. That way, I get a second possibly accurate domed pellet whose velocity is still on the good range.
JSB Exact Express
Ten pellets average 673 f.p.s., so just a trifle slower than the Premiers of the same weight. The range spanned from 662 to 681 f.p.s., for a 19 foot-second spread, which is about right for a new spring-piston gun. The average muzzle energy works out to 14.39 foot-pounds.
The rifle shoots slower than advertised — at least with lead pellets. While that may disappoint some readers, it doesn’t disappoint me, because I think the velocity is right where it needs to be for greatest accuracy. We’ll see if that’s correct in the next report.
The firing behavior is extremely smooth, and I’m still amazed at how light the rifle is. Bottom line is that it has good characteristics; and I think that if it’s also accurate, then we’ve discovered a major new rifle.