Gamo Big Cat - Part 3
by B.B. Pelletier
Gamo Big Cat is an impressive breakbarrel at an impressive price!
There's a new article about precharged pneumatics on the Pyramyd Air site. It's one I wrote for Airgun Illustrated magazine years ago, but I've updated it.
Today, I'll look at the accuracy of the Gamo Big Cat. You may remember that this inexpensive Gamo breakbarrel rifle has been getting high marks up to this point. It's light, easy to cock and the trigger is remarkably smooth. It also turned in a good showing in the velocity test in part 2. So, accuracy was all we had left to look at.
The Big Cat has no sights, so you have to mount some kind of scope or dot sight. It comes with a 4x scope for that purpose, and that's exactly what I used for this test.
I encountered some difficulty mounting the scope, and I want to tell you about it. I don't know if you remember, but in the past, and especially in the scope-mounting video I recently did, I mentioned that sometimes a scope will twist in the rings as it's tightened down. Well, the scope that came with this Big Cat did that to the extent that I had to fiddle with it for a long time to get it aligned correctly. By aligned, I mean sitting where the vertical scope reticle bisects the receiver. Every time I tightened the 2-screw scope caps, they twisted the scope just a little past plumb.
That tells me the rings are not in line with each other. And when they're tightened, they're torquing the scope tube (putting torsional stress on the tube in its tightened state). That can't be good for precision.
I also noticed that the scope was not clearly focused at the 21 yards I was shooting. Since it's only a 4x scope, it has to be pretty bad not to focus that far away, because you can barely see anything small enough to determine focus to begin with.
So, for those two reasons--the misaligned scope rings and the bad scope, I'll rerun the accuracy test with a better scope and different rings. However, the rifle did pretty good in spite of everything, plus the wind was gusting to 25 mph. So here is accuracy report number one.
Air Arms Diabolo Field
The Air Arms Diabolo Field pellet is an 8.4-grain pure lead dome that's made by JSB, so we know it's a precision pellet. In the Big Cat, they loaded easily and seemed to shoot well, but they also required extreme holding technique. If I slacked off the hold just a bit, the pellet would jump out of the group by a half-inch at 21 yards.
My best hold with the Big Cat was on the flat of my open palm. I tried the back of my fingers, but it threw the pellets around. Too much vibration, I think. However, the Air Arms domes were too twitchy to tell for sure.
Beeman Kodiaks were not as precise in the Big Cat. They spread out to 3/4" groups and didn't seem to want to do any better, so I didn't pursue them.
Crosman Premier 7.9-grain pellets
Crosman Premier 7.9-grain pellets turned out to be the best pellet I tried all day. They landed in tight groups and needed little in the way of special technique--beyond the standard artillery hold. In fact, they were forgiving of some sloppiness in technique, a situation that rarely happens with a breakbarrel. I have to say I was impressed.
That's a nice group for 21 yards on a windy day! Five Premier 7.9 pellets.
Another nice group, but the center has moved up and to the right. Nothing was done to the scope or the hold between this group and the last one.
This third group is also tight, but you can see that it's still moving to the right.
However, if you look at the three groups I show, you'll notice the impact point shifts to the right with each of the two groups after the first. As tight as these pellets are grouping, I have to chalk that up to either scope shift or parallax error; and, as tight as I'm grouping, parallax error doesn't seem to be the problem. This scope actually seems to be shifting--something that's very rare, in my experience. I don't know if it's due to the scope or the mounts at this point, and I'm not inclined to find out. I'll replace both for the next accuracy test.
The bottom line at this point is that the Gamo Big Cat seems to be a real value in a breakbarrel pellet rifle. On the plus side, it has an easy cocking action and a smooth trigger that's somewhat creepy but still quite nice. And that can be fixed with the addition of the GRT-III aftermarket trigger blade (read this report). The Big Cat is also lightweight and has a relatively smooth action. The power is right where it's supposed to be and the accuracy is fine. On the negative side is the amount of plastic used on the gun and the fact that it comes without sights.
The next report will be with a better scope and rings.