Benjamin Marauder PCP .177-caliber air rifle: Part 3
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, I’ll begin a look at accuracy for the Benjamin Marauder precharged pneumatic air rifle. If the Marauder was a normal PCP, this would be one quick report, but it isn’t. The owner has the ability to change not only the rifle’s power, but also the fill pressure the reservoir will accept. That makes testing a Marauder potentially complex if you want to try everything, and we certainly do want to do that here. So, today will just be a first look at potential accuracy, after which I’ll determine the shot count the rifle now gets with the best pellet, and then tune it to a preselected optimum range and test it again to see if the shot count increases. Neat, huh?
I know I’m going to shoot this rifle a lot, so I selected one of the best scopes I have — a CenterPoint 8-32x with parallax adjustment. The scope I chose is an old one from the time when Centerpoint was having Leapers make all their scopes. It’s no longer available, but a close equivalent would be this UTG scope.
Where to begin the test
Oh, boy, where do I start? I thought it would be good to test a number of premium pellets and try to find 1 or 2 that stand out for accuracy. Then, I’ll concentrate on those pellets, which will help me focus on what has to be done.
I shot at 25 yards indoors because that’s the distance at which things start to happen. If a pellet is going to be accurate, 25 yards is usually far enough for it to stand out.
This is one time where 5-shot groups come in handy. I decided to shoot all the pellets I’d selected in 5-shot groups and see if 1 or more of them stood out as exceptionally accurate. Five-shot groups save time, pellets and air; and when you’re faced with testing 8 different pellets, as I was, it makes a big difference.
If there was no favorite pellet, I would just have to pick a couple pellets and proceed to work with them. But as it turned out, this rifle does have a favorite. When I show you how much better it is than the others, you will probably say what my wife, Edith said when she saw the groups. She couldn’t believe that 1 pellet was so much better than all the rest, and exclaimed, “Woohoo,” involuntarily.
Marauder’s noise level
But before I get to that, when I walked into her office to show her the groups, Edith asked me what airgun I was testing because she couldn’t hear it. She thought it was some low-powered air pistol. And our female cat, who normally runs around the house complaining whenever I shoot, slept through the whole session. As it stands right now, the Marauder I’m testing is about as loud as a politician volunteering to do something proactive in a non-election year.
I selected the following pellets to test:
I did sight-in the rifle, but not so it would hit the center of the target because that would destroy the aim point. Nevertheless, a couple pellets did do just that. Fortunately, it was at the end of the 5 shots and no harm was done.
The Marauder is accurate no matter what pellets it shoots. It’s better with some pellets than others. Take a look at some of the 5-shot groups.
Okay, I could live with the JSB Monster group, and there were a couple other pellets worthy of further examination if that was the best the Marauder was going to do. But it wasn’t. When I shot 5 Crosman Premier lites, the whole test changed.
It should be obvious that Crosman Premier lites are the best pellet of those tested. On the basis of the 5-shot group, they’re twice as accurate as the next best pellet. Now, it was time to shoot a 10-shot group with them and see where that took us.
Obviously the 5-shot group was no fluke. This rifle really likes this pellet.
Where do we go from here? First, I’m going to fill the rifle again to 3,000 psi and shoot nothing but Premier lites to determine the total shot count with the gun as it’s currently tuned. You may remember that we found this rifle was tuned to the max when we did the velocity test in Part 2. While that high speed obviously doesn’t hurt the accuracy of the Premier lite pellet, wouldn’t it be nice to get several extra shots from a fill and keep the same accuracy? The rifle currently shoots Premier lites at an average 1,015 f.p.s., and I think an average 900 f.p.s. will be just as good. That’s where I’ll be adjusting the rifle. Several of you have asked how the power is adjusted on the Marauder, so this will give me the opportunity to show how it’s done.
Then, I’ll count the total number of shots at that new velocity, and we’ll see what reducing the velocity gains, if anything. I’ll also test the accuracy at the new lower velocity to see if the rifle is still just as accurate.
After that, I plan to adjust the maximum fill pressure of the rifle. I’ll experiment with the rifle operating at a lower fill pressure while still getting the same velocity. This will be at the new velocity of around 900 f.p.s. We’ll see what benefits there are to having a lower fill pressure.
I do plan on shooting the Marauder at 50 yards, too, but that will come after all the adjustments have been made and evaluated. By then, we should know the test rifle very well and be able to tune it for the best performance. There’s a lot more in store for this rifle!