Archive for April 2009
by B.B. Pelletier
Before I begin, another tidbit on the Pyramyd Air moving sale on Saturday, May 30. If you want to buy new items from the store, please bring a list of those items on paper.
Lots of interest in this rifle last week. Today, I’ll focus on the barrel. Although there are many interesting parts to the Marauder, some of the most anticipated features are centered on the tube with the spiral scratches. Just as a reminder, this barrel is American-made, choked, free-floated and shrouded.
I briefly mentioned that this isn’t a Lothar Walther barrel in the first report. It’s made by Crosman. Back when we were developing the basic requirements of the first- and second-generation PCP rifles Crosman would build, Crosman engineers were adamant that the second-generation barrel should be shrouded. I was equally adamant that it be choked. The subject of free-floating the barrel never came up in the discussions I attended.
Crosman has been making good barrels for decades, so it isn’t a challenge to make another. But a choked barrel was a new concept. They discovered that all their major PCP competitors were using choked barrels, so just being able to put that into the ad literature was bragging rights by itself, but was it really important?
I can cite history–where famous barrelmaker Harry Pope clearly felt that a half-thousandth choke at the muzzle was a good thing. The intriguing thing is that many of Pope’s most accurate barrels were for muzzleloading rifles–yet they were still choked. Yes–the choke does squeeze the bullet down smaller than the rest of the bore as it enters the barrel; and no–lead does not “spring back” after being squeezed. But upon firing, the pressure of the explosion whacks the base of the bullet so hard that it squashes out to fill the bore tightly. This obstruction of the bore is called obturation, and all blackpowder arms do it. Diabolo pellets also expand at the skirt when hit with high-pressure air at the start. The force of the air is not nearly as great as the force of exploding gunpowder, but the skirt is made of thin lead and flexes more easily.
The choked muzzle then squeezes all exiting pellets to the same size as they leave the bore. And that’s been proven to increase accuracy. We shall see when we test for accuracy.
In firearm rifles, a free-floated barrel allows the barrel to move as it heats up from firing. Since it doesn’t contact any part of the stock–the definition of free-floating–it never picks up a secondary point of contact to disturb its vibration. It’s free to vibrate the same with every shot–the same condition we strive for with the artillery hold. Free-floated barrels have long been known to improve accuracy over barrels that touch the stock along the forearm.
In a PCP, as the reservoir loses pressure, it flexes. If the reservoir is connected to the barrel, it will pull the barrel along with it as it moves. A free-floated barrel is not connected to the reservoir at any point. It tends to be accurate over the entire string of useful shots. In some rifles, like those from AirForce, the barrel is separated from the reservoir, so free-floating isn’t an issue. But in a rifle where the reservoir runs parallel to the axis of the bore, the potential for barrel movement due to reservoir flex is greatest.
One thing I must note is that the Marauder barrel shroud clatters a little when the rifle is handled. Actually, it’s the barrel inside that’s free to move around that causes the clattering. If you want a free-floated barrel, you have to put up with a little movement, and with the shroud being so close to the barrel, that means a slight bit of noise in the Marauder. Crosman engineers tell me they are working to minimize the noise, but I have to report on the gun I’m testing.
Okay, here’s the thing so many want to know about. The shrouded barrel. Is it baffled? Yes, it is. How much quieter is it because of the baffles? Not much.
Huh? I thought baffles were THE thing for quiet rifles. Well, they can be if they’re needed and if they’re placed and spaced just right. But the muzzle of the Marauder is buried so deep inside the shroud (nearly 6″ from the outside of the end cap) that you can remove all the baffles, put the end cap back on and the rifle sounds almost the same. I just tried it and although I can hear a difference, it doesn’t amount to much. Maybe with a good sound meter that can freeze the high readings. If you had one that works fast enough to catch the fast peaks, there might really be a difference. But that’s like saying it’ll matter to your Collie but not to you. This rifle is quiet. Period. End of report.
No. Not the end. Not yet. I must be honest and revise my appraisal of what the rifle sounds like with the baffles installed and shooting a 10.5-grain Crosman Premier pellet at about 920 f.p.s. It sounds a lot like a Sheridan Blue Streak firing on one-quarter of a pump of air. Yes, that is louder than a ballpoint pen falling on a carpet. To all who went out and purchased ballpoint pens and had their homes recarpeted just to see what the Marauder sounds like so they didn’t have to risk buying one and being disappointed–I apologize. It’s still quieter than most weak spring rifles.
The end cap unscrews to remove the baffles that are just loose inside between the muzzle and the end cap. The shroud also unscrews so you can see the barrel. as shown in this report.
Accuracy is also a barrel thing, but I’m not putting it here. We’ll have to get to it on a day all by itself. I’m thinking Friday.
by B.B. Pelletier
Before I begin, here’s the news on the Pyramyd Air garage sale. It will be held on Saturday, May 30, from 9 a.m to 5 p.m. The location is the current Pyramyd Air building, so the address is on the website right now. I have a LOT more to tell you in the coming days, plus we still want to hear what YOU expect to see.
Now, settle back, kids, and daddy will tell you all a long story about the Benjamin Marauder.
First, there was the Benjamin Discovery, which sold more rifles in the first year than many PCP models have EVER sold. The engineers at Crosman (Benjamin and Sheridan are trade names owned by the Crosman Corporation) had many great ideas when the Disco was being developed, but the most important thing was to build a basic precharged pneumatic (PCP) rifle that could be sold at a remarkably low price while offering incredible value. That project was a clear success.
Phase Two was the next gun that the engineers were promised would have all of their cool ideas. It would be a world-beater PCP, with all the right bells and whistles. And one additional thing. Because it would be made in America by a factory that knows how to control production costs while maintaining quality, it would be affordable. Not cheap, but affordable. This is the report of that rifle–the gun they call the Benjamin Marauder.
Overview of specifications
The Marauder is a 10-shot repeating PCP that comes in either .177 or .22 caliber. I tested a .177. It has a bolt-action and the magazine is spring-operated, so pellet feed is positive and without friction. Therefore, the Marauder is one of the slickest bolt-action PCPs on the market. Or it will be when it goes on sale in May.
The rifles that Crosman sent out to airgun writers are pre-production models with a few small differences yet to be made. In my reports, I’ll detail what these differences will be.
The stock is fully ambidextrous with palm swells on both sides of the pistol grip and a rollover cheekpiece that’s identical on both sides. Except for the operation of the bolt, the rifle is ideal for both left and right-hand shooters. The stock is very conventional, with a high cheekpiece for scope use. There are no open sights, so a scope must be used.
The trigger is fully adjustable for length of first stage, length of second stage and pull weight. It breaks as crisply as the proverbial glass rod–a fact I will show you via a computer analysis in a future report.
The fill port is a male Foster quick-disconnect with an internal micron-sized air filter. That ensures only clean air can flow into the reservoir.
There’s a purpose-built pressure gauge on the underside of the forearm. It will be marked up to 3,000 psi, for which you’ll learn the reason next.
Adjustable fill pressure
The Marauder lets the shooter change the gun’s fill-pressure. What that means is the owner can “tune” the gun’s firing valve to work with air pressures of 2,000 psi up to 3,000 psi. Why would you want to do that?
If you wanted to operate the rifle on BOTH air and CO2 (though never both at the same time–always one or the other), you’d have to adjust the firing valve to operate on a fill of 2,000 psi air. CO2 pressure changes with temperature, alone, and cannot be changed mechanically. So, for the valve to fully open and work properly on CO2, it has to be adjusted to operate on air at 2,000 psi. I believe that is how the rifle will be set at the factory. Crosman had not made up their minds when this report was researched; but since they’ll be advertising it as a Dual Fuel rifle, it makes sense.
If, however, you wanted to operate only on high-pressure air and were interested in getting the longest string of good shots possible from a fill, you would set the valve to operate at 3,000 psi. The CO2 operation would be lost (until you reset it to 2,000 psi), but you could expect to get several more shots in the optimum power curve at the higher fill pressure.
It’s possible to set the rifle to operate on a fill pressure between 2,000 and 3,000 psi. There would be no special advantage to doing so, but understand that this capability (setting the fill level to 2,000 or 3,000 psi) is not a discrete thing. There’s a scale of fill pressures between the two limits, and the fill can be set anywhere.
Final point–setting the fill pressure does not change the velocity of the gun, at least not directly. The velocity is adjustable and will cover it next, but first you need to understand that the fill pressure does not determine the velocity.
Oh, and one more thing. As far as I know, the Marauder is the only PCP that permits this kind of adjustment without exchanging parts inside the gun. It’s the only gun that lets the owner do this and even explains how to do it in the owner’s manual. You’ll need a chronograph if you plan to adjust the rifle this way.
Okay, THIS is the thing most people will be interested in. The Marauder adjusts velocity in a way that’s entirely different than any other PCP on the market. With all the others, you dial a wheel or flip a switch. Whatever velocity that gives–that’s it. That’s what you get. Want something different? You either have to move the adjustment or shoot a different pellet.
The Marauder lets you select the exact velocity desired for a given pellet (within the scope of the rifle’s capability) and to set it. Once set, that pellet will shoot at that velocity, within reason, until the end of the fill.
In the 1870s, American buffalo hunters loaded their blackpowder single-shot rifles with just a single kind and weight of bullet, which they personally cast in a mold. They loaded the cartridge with a certain amount of powder that never varied, plus they lubricated the cartridge in a certain prescribed way. This recipe never changed, and these rifles were capable of putting five shots inside a 5-inch circle at 500 yards. The Marauder is very much like that.
Instead of a rifle for 20 different pellets and velocities, the Marauder wants to be set at the best velocity for the best pellet. In the coming weeks, I’ll share what my experience has been in determining that pellet.
Velocity and fill pressure are interdependent
If either one of these variables changes, the other will also change. When you set the rifle up, you have to find a balance between both variables. It isn’t difficult to do, but it’s a complex relationship. That’s why I said earlier that a chronograph is needed to adjust the fill pressure.
But you don’t have to do anything if you don’t want to. An owner can just take the rifle from the box and shoot it the way it came. These adjustments, which have never been available to those who are not airgunsmiths, are unique to the Marauder when it comes to production air rifles.
Well, it’s not a Lothar Walther! But it’s probably just as good. For starters, it’s a choked barrel. A choked barrel has a slight constriction at the muzzle end that sizes all pellets passing through, so they emerge with the same diameter. Rifle chokes have been known since the late 19th century as a means of getting the best accuracy from a barrel. When jacketed bullets began to replace lead bullets in the 1890s, choking went away, but in PCPs it’s recognized as the mark of a premium barrel.
The barrel is free-floated. That means it doesn’t touch the reservoir. As the pressure inside the reservoir drops, the reservoir flexes–and if the barrel were touching it, it would move. But the Marauder barrel is fully free-floated.
The barrel is shrouded. The rifle is therefore quiet.
Drop a ballpoint pen onto a deep-pile carpet.
So quiet, in fact, that you cannot hear the muzzle report (or at least I can’t). All you hear is the musical ping of the hammer spring releasing.
So quiet that 50 feet away, it’s doubtful anyone could hear it.
I own a legal silencer for a .22 rimfire. It silences the gun by 41 decibels. This rifle is quieter than my Ruger 10/22 rifle shooting CB Caps (no powder, only priming compound) through the silencer.
Over the past several months, I’ve made several of you promises about this rifle. You were looking for a quiet PCP air rifle, and I told you to wait. You were looking for an accurate air rifle, and I suggested you wait. Well, the waiting is almost over.
Crosman will release the first small batch of Marauders directly from the factory starting in May sometime. They will limit that release to about 100 rifles. They do that so they can warm up the production line while keeping a sharp watch on what’s being shipped. If you buy from them, expect to pay full retail, which will be a nickel under $500.
If you wait for Pyramyd Air to receive their rifles in June before placing your order, you’ll probably realize a small discount. Nobody told me that, but I have watched enough of these things to think it will happen that way.
Finally, as you can see from this lengthy first part, I have a lot more to tell you about this rifle. For each feature I glossed over today, like the trigger and the velocity setting, I’ll come back and give you a compete and detailed story. So, this report is going to be a long one!