Ruger Air Magnum Combo – Part 3
by B.B. Pelletier
Photos and testing by Earl “Mac” McDonald
Hopefully, I’m getting this test finished in time for a few last-minute buying decisions for the holidays. I’m sorry it takes so long, but time being what it is, it’s the best I can do without turning this blog into an infomercial.
Today, we’ll look at the accuracy Mac was able to get from this powerful new übermagnum spring rifle. I know many of you were predicting it wouldn’t be very good, given the power output.
This is also the day when Mac will show you how to adjust the parallax of a fixed-parallax scope so you don’t have to buy a new scope to get what you want from the gun. Since that’s an interesting procedure, let’s do that first.
I was exposed to this trick back when I shot field target. Many shooters were changing the parallax on scopes with fixed parallax back then.
Step 1. Remove the threaded trim ring on the objective bell. On this scope, you’re lucky, because that exposes a cross-slot on the objective lens unit that lets you insert a thin screwdriver blade. Because of the wide span that must be crossed, a thin knife blade is often the best tool for this job. By turning the objective lens assembly slowly in either direction, the entire objective lens assembly can also be turned.
Step 2. To adjust the scope for a different range, turn the objective lens assembly while checking the sharpness of the focus on an object set at the range you wish to adjust to. Turning this assembly out adjusts the focus closer — and in moves it out farther. Unless you completely remove the objective lens assembly from the scope, no nitrogen will be lost, as the extremely viscous grease on those fine threads perfectly seals the inner part of the scope. If the seal is broken, though, the scope will be compromised and will fog up unless it’s resealed.
Step 3. Once you’re satisfied the scope focuses where you want it (i.e., the parallax is set where you want it), replace the beauty ring to lock the objective lens assembly. The job is now done.
Mac tells us that the rings that come with the rifle are nice and appropriate. They have four screws per cap and each ring has friction tape inside to prevent scope movement. Don’t do what Kevin said someone did and remove the tape because it doesn’t align quite right. Keep your hands off that tape! It’s there to do a job; and if it’s removed, the hole through each ring gets bigger.
Mac noted that the nameless scope seemed to be adjusted for the 30 yards he was shooting, so there was nothing more to do but sight-in. As first tested, the rifle shot just two inches low, with no noticeable left or right deviation. That little amount is what the scope knobs can do by themselves, so there was no need to adjust the scope mounts in any way.
Next, Mac started the testing with some Crosman Premier 10.5-grain pellets. Ten of those grouped into a pattern that measured 2.7 inches at 30 yards. Mac calls this poor, and I have to agree.
Next, he tried 10 RWS Hobby pellets that we all agreed are too light for this powerplant. They held 9 in a group measuring 2 inches even. A tenth shot was a called flier that missed the target paper altogether. This is another pellet not to try.
Except for the called flier, these RWS Hobbies grouped better than the heavy Premiers, but notice the dark edges of some of the pellet holes. Clearly, this pellet is wobbling on its way downrange –something that can’t be determined from the less-precise holes of the Premiers.
Then, Mac loaded 10 JSB Exact Diabolo heavies, the 10.2-grain domed pellets that often work best in powerful air rifles; and, again, they did their thing. They gave a 10-shot group that measures 1.1 inches at 30 yards, which is acceptable hunting accuracy.
Just for the record, Mac also fired 10 RWS Superdomes and 10 RWS HyperMAX pellets at the same distance. The groups from both pellets were too poor to measure. We know that the 5.5-grain HyperMAX pellets were traveling over 1,400 f.p.s. and could not be expected to be accurate. But, why were the Superdomes also a problem?
RWS Superdomes are almost pure lead, plus their skirts are very thin. In a rifle shooting 800 to 900 f.p.s. that’s perfect, because the rear of the skirt blows out and seals the bore behind the pellet. But, in a powerhouse like the Ruger Air Magnum, it shoots them well above the sound barrier. The thin skirt is blown all the way out until the pellet resembles a cylindrical can with a slightly domed top. Since the wasp waist is where the accuracy comes from, it’s not good to lose it this way. The pellet is then free to fly wherever it wants, destroying accuracy. If Mac could recover some of these pellets without damaging them, that is what we would see.
But, that doesn’t matter, because Mac has found a good pellet for the rifle. Putting 10 shots into 1.1 inches at 30 yards is certainly good enough for hunting. At this power level and price point, I think this is one spring gun you’ll want on your short list.