Benjamin’s Rogue ePCP — a new way of making airguns: Part 3
by B.B. Pelletier
I spent the day at the range last Friday with the Benjamin Rogue. It was like a first date, as I had no idea of what to expect. With other new airguns, there’s always information from the developers or at least there are the physical specifications to go by. With the Rogue, I was starting from scratch.
Oh, the Crosman engineers had been very forthcoming with their testing anecdotes, and as for experience, there was a bundle of it already in the bag from gun writers who both saw and shot the rifle at the SHOT Show on Media Day. Unfortunately, the anecdotes were told to me in Martian — a language without a universal translator. Crosman engineers understood very well what they were saying, but without a common frame of reference, I had no clue. The little field experience there was came from gun writers, as in, “Golly, Jimbo! It’s a three fifty-seven BB gun! Whad’ja think of that?”
What we need, to make sense of this new rifle, is someone who’s shot other big bore air rifles and can compare them. And, in this case, that’s me. So, there I was, on a first date.
Here we go. First, I filled the gun in a very conventional way. The Rogue has a male Foster quick-disconnect fitting, so my standard female Foster fitting on my carbon fiber tank fit without a hitch. I filled to 3,000 psi, because that’s the maximum pressure for which the electronic valve is set. With a Quackenbush Outlaw Long Action rifle with a purely mechanical action, you know the nominal fill limit is 3,000 psi, but every rifle will accept a little more than that. So, your first trip to the range consists of filling to progressively higher levels until the actual fill pressure for your individual rifle is discovered. My Quackenbush .458, for example, takes a max fill of 3,500 psi and gives two powerful shots in the 500+ foot-pound region. Then, it’s time to refill. If you attempt shot three, as my buddy Mac did a couple weeks ago with his .458, you can stick a bullet in the barrel — like he did.
But the Rogue is completely different. The onboard computer controls the firing valve to release exactly the right amount of air, depending on how much air was in the reservoir, the weight of the bullet fired and what you want the gun to do. You control all this through commands that you input into the onboard controller. When they say the max fill is 3,000 psi, it really is!
Crosman sent me bags of several different lead bullets to try, plus Nosler shipped me a sufficient quantity of their new Benjamin eXTREME Bullet with Ballistic Tip. It’s a 145-grain lead bullet designed expressly for the Rogue. One look at it and you know that someone who knows big bore airguns had a hand in its design.
Nosler’s eXTREME bullet with ballistic tip for the Benjamin Rogue is designed to create minimum friction with the bore by touching the lands only at the driving bands. A hollow cavity in the base obturates when the rifle fires, sealing all the gas behind the bullet — just like a Minie ball — for maximum efficiency.
This is the round that shocked all the gun writers at the 2011 SHOT Show Media Day, when it outperformed a .223 AR-15 on a coyote silhouette at 75 yards. The fast-moving, lightweight centerfire bullets simply exploded on the steel target, while the big Nosler hammered down the silhouette every time. Of course, the smaller bullet was simply vaporizing too quickly to transfer its energy to the heavy steel target, even though it actually delivered many times the impact energy of the Rogue. But seeing the airgun flatten the steel silhouette was the mental impression the writers carried away.
This is the bullet I selected to begin testing. I know what you want right now is a chart of velocities with the bullet. Well, I can’t give that to you — yet. There’s more testing to be done, as you’ll see shortly.
What I can tell you is that, when the rifle was at 2,421 psi and the power was set to medium with a 145-grain bullet programmed, the Nosler bullets went 760 f.p.s. on the first shot and 700 f.p.s. on shot six. The pressure dropped from shot one (2,421 psi) to the end of shot six (1,773 psi). Each shot used just over 100 psi of air. Although I didn’t have to, I stopped after shot six and I’ll tell you why.
I’d chosen this pressure and power setting with the Nosler bullet to shoot a group at 50 yards. But like I said, this was a first date and you sometimes don’t find out what you need to know until you go too far, so I kept shooting at the target until shot six strayed way over to the right, opening the group from about 1.5 inches to 3.2 inches, effectively doubling the group size. This wasn’t the first group I had shot, and by this time I knew that when the bullets went to the right, they were not coming back.
The first three shots can almost be covered by a quarter or a Euro. Shots four and five moved to the left, while shot six moves way to the right. Had I continued to shoot the shots would probably have continued to the right or started dropping lower on the paper.
Let’s take a closer look at that target. Within the group listed and shown above, the first three shots clustered in 0.736 inches between centers. In fact, two of those three shots took out the exact center of the target. In this group, which began at 2,421 psi on medium power using the 145-grain Nosler, I got a superb three-shot group, a good five-shot group and indications that shot six and all that followed were going to open the group much larger. For the record, the first shot produced 186.02 foot-pounds of energy at the muzzle, while shot six produced 157.8 foot-pounds. Shot five, which was where I would stop in the future with these settings and bullet, went 724 f.p.s. and produced 168.81 foot-pounds. All of that was on medium power with a starting pressure of 2,421 psi.
Is this a bit confusing? It was to me at the beginning of the test. When you think about all the possibilities this system offers, you’ll see that you could spend the rest of your life exploring the possibilities and never test them all. After shooting over 50 rounds, it began to sink in what I was doing and how this gun really works.
You could spend the rest of your life exploring the possibilities and never test them all.
How the Rogue works
You tell the gun what weight bullet you’re using, from a choice (with the current software) of 100 grains, 145 grains or 170 grains. Set the number as close as you can to the actual weight bullet used. Then, you tell the gun to shoot on low, medium or high power. The rifle knows how much air is in the reservoir, so it factors that into the equation to determine how long to leave open the firing valve to give as consistent a velocity as possible for as many shots as possible — all things considered.
However, you don’t just set these controls without thinking. For example, if it’s power you want, use the heaviest bullet available, set the gun for 170 grains and high power. If you want lots of shots, select a lighter bullet, a lighter grain setting, and a medium or even low power.
Let’s set the numbers and settings aside for a moment. There’s also the target to consider. If you can generate big numbers but have an open group downrange, it doesn’t help you very much. What you’re looking for is the right bullet at the right power, given the right pressure in the gun for the best results downrange, and that takes some time to figure out. What I’ve shown you to this point is one of about ten such test targets that I shot and tracked last Friday. When I can make more sense out of the rifle’s performance curves, I will report it.
Yeah, but how many shots does it get?
Some folks don’t want to see behind the curtain. They just want results. Right now! For them, I offer the following. Here are the first 13 shots I fired with 145-grain Noslers on medium power before the rifle was sighted-in. I started from a 3,000 psi fill and just kept shooting shot after shot. I think the picture will explain itself.
Here are 13 shots in rapid succession at 50 yards. All are the 145-grain Nosler bullets. Note the tight central group, then the two shots above that group and the two below. The four outlying holes were the last four shots fired, with the bottom two being shots 12 and 13. As the reservoir pressure declines below a certain point for each bullet, the group starts to open up. Although I was chronographing these shots, the chrono was misbehaving, so I didn’t get any of the velocities until shot six, which was 705 f.p.s.
On this same day, I also tried bullets weighing 90 grains, 127 grains, 167 grains and 178 grains. I’ll report on their performance in the future, but as you can see, there’s a lot of detail to the testing I’m doing. I don’t want to report anything until I can make sense of it for you.
The longest string
The longest string I shot all day without topping off was 16 rounds. But I changed bullets and power settings in that string, so it can’t be taken as a whole. It’s really three tests rolled into a single fill. But 16 shots on a fill is more than I’ve ever gotten on a big bore of any kind, even from those older lower-powered guns — like the Farco — that use CO2.
The range session ended when I attempted to shoot a hard-cast .357 bullet in the rifle. It would not enter the bore, stopping at the beginning of the rifling. Hard-cast bullets are used by those who wish to handload .357 Magnum pistol rounds to higher velocities because they don’t melt and deform at the base like softer bullets do. But they also take far more energy to engrave the rifling into the bullet, and that was why I couldn’t load this one. It got stuck in the bore. Since I didn’t have a steel rod to push it out, that ended the session for the day. Note to self — always carry a GI sectional cleaning rod in case this happens again, and DON’T use hard-cast bullets in the Rogue!