Posts Tagged ‘PCP Marauder’

Hunting in South Africa: Part 1 by Jim Chapman

Wednesday, October 28th, 2009

Introduction
As an outdoor writer, and moreover one specializing in hunting airguns, I get to shoot a lot of airguns. There are many good rifles being produced today, and a few great ones. But what we have been missing is a great hunting airgun at a price point most hunters can afford. In a marketplace that is populated by guns starting at over a thousand dollars, not to mention the cost of adjunct gear such as filling equipment, it is difficult for new shooters to enter the sport. That is why I got excited when Crosman entered the precharged pneumatic arena, first with the Discovery then following with the Marauder.
The Discovery is a single shot PCP rifle that has everything the airgun hunter needs in an entry level gun; it is accurate, powerful, and reliable, fills to a low charge pressure with a handpump, and can run on CO2 for lower powered indoor shooting. But the truly compelling thing with this rifle is that packaged with a handpump it cost far less than anything else the airgun hunter could buy. I was lucky enough to be sent one of the first pre-production guns to shoot, hunt with, and give some feedback on. But truth is that I think the engineers and market research people got it just about perfect and delivered exactly what the market wanted and needed. However, there was room for a higher tier rifle that bridged the simple no frill design requirement of the Discovery and the more sophisticated (and much more expensive) rifles at the high end of the price/performance spectrum. While I really like the Discovery, I thought it would be perfect if there was an option to get it with a shrouded barrel, and if there was an option for a premium trigger to be installed by their custom shop (even if that cost a few hundred dollars more), and if there was a multi-shot version. That was the point; this gun hit so close to the mark that the only thing needed to make it a better gun were features only found on much more expensive rifles!

Then a couple years later I received word that Crosman had a new PCP rifle in development, and again was offered a pre-production gun for evaluation. The Marauder was unveiled at the 2009 SHOT Show in Orlando; and what was introduced to the airgunning world was a rifle offering features previously found only on much more expensive models. The Marauder has a 10 shot rotary magazine, a sophisticated match grade adjustable trigger that is a dream, and comes standard with a shrouded barrel that is whisper quiet. This in addition to the Marauder’s intrinsic accuracy and the power to take any small game from squirrels to woodchucks, has resulted in a gun I love to carry in the field. As a matter of fact, I selected the Marauder as my small game rifle for an airgun safari in South Africa’s Eastern Cape, which in past years has been a challenging testing ground requiring a gun to shoot with precision, hit hard, and be reliable. When you’re thousands of miles from home, it makes sense to only carry gear you believe in. The Marauder has proven itself to me.
My intention with these hunts was to demonstrate that the Marauder is the real deal for small and medium game hunting, and that they can be used to make one shot kills that cleanly anchor the tenacious small game and pest species in this hunter’s paradise. Even though this book was based on hunting in Africa, the experience speaks directly to the guns suitability for hunting anywhere in the world.

Hunts were setup over a five week period in South Africa, and I planned to make the most of the hunts. My friends and professional hunters Rob Dell and Andrew Myers were contacted to organize the trip. From my Indiana based office I was phoning sponsors; Crosman for guns, scopes, and pumps to be drop shipped for pick up on my arrival to the Eastern Cape, Pyramyd Airgun, arguably the biggest and one of best airgun supplier in North America came through with financial support, and Adventures in airguns supplied additional equipment. It all came together and formed one of the most enjoyable hunts of my life.
In this small booklet my objective is to share several facets of hunting with the Marauder, relating our experiences regarding the guns, the gear, the people, and the game. And in the end I believe you’ll see that if you own a Crosman Marauder, you have a gun that takes you anywhere you want to go.

Hunting with Airguns
There is a long tradition of hunting with pre-charged pneumatic (PCP) air guns, dating back to the late 1600s when big bore air rifles were used by European nobility to take large game animals. In more recent years, spring piston airguns became available to the masses, and after World War II there was a dramatic increase in the availability of guns. The sport has continued to grow in much of the world, especially in those locales where gun ownership is not an option for the civilian population. In Europe there is a tradition of high quality airgun manufacturing, especially in Germany and the United Kingdom.
As a matter of fact, the UK has arguably been the center of the modern airgunning world. They produce many of the finest spring piston and PCP airguns in the world; and support a vibrant airgun hunting community with a couple popular magazines dedicated to reporting on and promoting the sport. And while the range of available guns offered to the market comprises both spring piston and PCP power plants, there has been an upsurge in the popularity of precharged pneumatic guns in the market over the last decade.

In the United States serious airgun hunting has been relatively unknown, and even less so when it comes to PCPs. However, as Americans are faced with increased urbanization, the attraction of the air powered hunting arm becomes ever more apparent; providing a means of hunting in areas that are more densely populated where firearms are a no-go. While many hunters feel that PCPs are easier to shoot accurately and tend to be more powerful than spring piston guns, the fact that there has been a dearth of appropriately priced PCP guns for the American sportsman has blocked a lot of new hunters from entering the sport. With Crosman’s release of the Discovery and the Marauder, this is going to change in my opinion!

In this book I will examine how these new Crosman guns can be used for field work, and relate some firsthand experiences coming out of our five week airgunning trek in South Africa, in which I relied solely on the Marauder and the Discovery for small game hunting.

Why Hunt With Airguns?
As stated previously, in Europe and much of the world airguns are the only option available to people wishing to hunt. They simply are not allowed to possess firearms, or the population densities are so high that there is not enough open land to hunt over. But there are several reasons that shooters everywhere appreciate; airguns are relatively quiet (in the case of the Marauder, less than a whisper) and have a limited carrying range, they can therefore be used to perform pest control duties and hunt in fairly populated areas, and due to the limited range can even be shot safely in the backyard or down in the basement. The cost of airgun projectiles is much lower than even .22 rimfire ammunition, with pellets costing a penny or two per round. The challenge of the hunt is increased with airguns, because to ethically take game the hunter must close the distance which requires honed hunting skills. In this respect airgun hunting offers many parallels to bow hunting while incorporating traditional marksmanship.

The modern PCP airgun is capable of tack driving accuracy out to sixty or seventy yards, while most springers can be used with confidence out to thirty five or forty yards. Another benefit is that the hunter can get in a great deal of practice. I will often go down to my basement range and put a couple hundred rounds through a gun I’m getting ready to take with me into the field. You’re not going to be able to do this with a firearm unless you happen to live on a ranch in Montana.
The last reason on my list is the least tangible …. Airguns are cool! There is something about the engineering that goes into these guns, along with the diversity in designs available that makes airguns a highly addictive past time. The airgun uses a tiny puff of air to send a fifteen or so grain piece of lead down range to anchor their quarry! This is a fact that always amazes me…

by Jim Chapman

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All right folks that is all for part one, we will be posting the rest of the book a few chapters at a time over the next few months. After that the full book will be available to download.

Thanks for reading.

Joshua

Marauder Single Shot Tray is available…

Thursday, October 15th, 2009

Since releasing the Marauder we have had one accessory request more than any other, a single shot tray. Well we heard you loud and clear. The new single shot tray slides in the same channel that the multi-shot clip fits in and allows for a single round to be fired from the Marauder. The single shot tray is available in the PCP Accessories section of the site. Here is a link…

PCP Accessories…

Keep your suggestions coming. We’re listening.

Joshua

Airgun Hunting in South Africa with Jim Chapman…

Monday, October 5th, 2009

Jim Chapman hunting South Africa
Today on Croswords we are taking a few minutes to talk with noted airgun hunter and writer Jim Chapman. This past summer Jim took the Benjamin Marauder on a hunting trip to South Africa and carefully chronicled his journey. He collected all these notes and pictures into a book that we will be sharing with you over the next few weeks here on Croswords. Before we dive into the book I wanted to take a few minutes to ask Jim a few questions about his trip and his love for airgun hunting…

Jim, for our readers who may not be familiar with you and your globetrotting exploits, please introduce yourself and tell readers about your website.
Well I think my experience is not all that different in terms of hunting; when I was a young boy my uncle gave me an old BB rifle that I cleaned, and then used for the summer terrorizing sparrows and gophers. I went through the normal stages of rimfires for small game, shotguns for upland game, and eventually centerfires for big game. After college I left the States and moved to Europe for several years, followed by Japan then Australia, I was away for the better part of 20 years. It was while I was living in Europe in the early 80’s that I was introduced to adult airguns. I like to shoot and since you couldn’t own a firearm in those places I gravitated to airguns once I found out about them. I get to travel all over the world for my work, and have had the opportunity to hunt and shoot in many places. My wife is South African so I’ve been spending a good part of my summers down there for many years, where I always get in as much hunting as I can.

How long have you been hunting with Airguns?
I guess I really became serious about airgun hunting in the late 80’s. I was asked to run a couple projects in Asia and (what was then) Eastern Europe. I moved my wife and son back to the States to be near family, and I alternated between a month abroad and a month back in California. When I was back at home I had a whole month that I didn’t have to work. I hunted almost every day during that period, and often with airguns. That was a fun couple of years!

Why Airguns?
I do a lot of wingshooting and hunt a lot with firearms and bow, but airguns are my favorite. To airgun hunt the way I believe it should be done means getting in close (30-50 yards), which hones your skills as a hunter. I’ve always thought of it as a cross between archery and firearm hunting, as it uses skills from both. Another factor is that I have a busy life and airguns give me an opportunity to hunt closer to home. Because you can safely shoot them just about anywhere, it opens up property for me to hunt where a firearm, even a rimfire, is not going to work. Firearms generate too much noise, too much power; you’d be surprised how many places are opened up to hunt when you don’t have to worry about those two issues.

Do you have any favorite game you like to hunt with airguns?
There are so many species you can hunt in different parts of the country; but I’d have to say that tree squirrels in the Midwest and jackrabbits out West are my favorites. Both of these species require the same hunting skills I use when hunting big game. It’s funny, I get the same charge of adrenaline when shooting a squirrel I stalked, as when I’m lining up on a whitetail. But unlike deer where I might shoot three or four in a season, I can get many shots on a two hour squirrel hunt. Of all the small game animals I hunt with an airgun, guinea fowl in Africa are my favorite. These birds are big, they are fast and they are wary. I think they represent the ultimate airgunning challenge.

Tell us about your adventure to South Africa?
I have hunted in South Africa a lot, with firearms and airguns. I received special permits to hunt big game with bigbore air rifles, and have taken everything up to kudu and warthogs. We always choose standard caliber airguns to bring with us to hunt small game and for pest control at my friends farm, and it always turned out to be great fun. On this last hunt I decided to focus on the small game, and it was an excellent call! We had a great time and I think when readers look at my little Marauder Journal they’ll see why.

What led you to South Africa?
My wife is South African and we have family we like to visit there every year. But more importantly, I have two friends that are professional hunters named Rob Dell and Andrew Myers. Andrew stared hunting with airguns while living in the UK, and Rob is an outfitter (Hounslow Safaris). Rob’s family owns a large property in the Eastern Cape. These guys have become specialists in airgun hunting in South Africa.

You took the Benjamin Marauder with you. What did you think of the gun and its performance?
I wanted a gun that offered excellent performance (accuracy and power), that was multishot capable, and that was reliable. And even though noise was not a huge issue on the farm, I wanted a quiet gun as I also had the chance to hunt on friend’s vineyards back near Capetown where noise was an issue. I had four guns with me, a .22 caliber, two .177 caliber Marauders and a .177 Discovery. We shot thousands of pellets between the three of us, and the guns functioned perfectly.

Is it difficult to travel abroad with an airgun?
Of course depends on where you’re going, but in the case of South Africa it is easier to travel with airguns than with firearms. What made it much less complicated was shipping the airguns over in advance, which you cannot do with firearms. That step made the whole process (outside the 32 hour travel time) much easier.

What game did you hunt?
We hunted wild pigeons, guinea fowl, carrion crows, Egyptian geese, hyrax, mongoose, springhare, rabbits, and many pest birds. What was wild was not only the types of animals, but the sheer numbers of them. My friend’s property is about 10,000 acres with hundreds of thousands of acres of reserve and farmland around it. You should understand that in South Africa all properties are called farms; they are what we would call ranches. Even though only a portion of the land was used for livestock, areas where there was feed drew pest species from far and wide. I left two Marauders on the farm where they are used every day for pest control. It’s kind of cool, Rob lives in a place surrounded by all kinds of big game and he carries his Marauder in the back of his truck for pest control when he heads out. I tell you, I made big points leaving those airguns behind as gifts!

Was the trip successful and would you take the Marauder again?
I love the Marauder. Sure, there are a lot of good products out there but nothing comes close to the rich feature set, the performance, and the quality of this airrifle, anywhere near the price point. I’ve taken several small game guns out over the years and the Marauder would be high on my list to use again.

What is your next big adventure?
I’ve got several hunts lined up this year; I’ll be airgun hunting in Texas, California, Indiana, Missouri, Kentucky, California, and Colorado for all kinds of game. But I think the next long trip will be somewhere in South America. I’m looking for a place that offers
something unique …. But I don’t know what yet.

I would like to thank Jim for his time answering these questions for us. Look for the first chapter of his book here on Croswords starting next week and follow Jim’s continued adventures at his website, American Airgun Hunter

Thanks for reading everyone.

Joshua

The Marauder and I by Jim House

Monday, August 3rd, 2009

First impressions are not always reliable. During a quick look at an object one feature may be noted and even that not in an objective way. Given an extended period of experience with the item, an entirely different perspective may be developed. With the Marauder and I, it was not necessarily love at first sight. But given the sterling qualities of the Marauder, we are now the best of friends. Let me tell you the basis for that friendship and how it developed.

My friend, the Benjamin Marauder, is a precharged pneumatic air rifle that is available in .177 and .22 calibers with velocities of up to 1,100 and 1,000 ft/sec, respectively. The reservoir can be pressurized up to 3,000 psi with air or the rifle can be used with carbon dioxide in the reservoir. In which case, pellet velocity is lower because the vapor pressure of carbon dioxide is not nearly as high as the permissible pressure with air. Not only is the Marauder a precharged pneumatic, it is a 10-shot repeater. The pellets are held in a rotary magazine that fits in a slot across the receiver, and a rotary section inside the magazine is spring loaded. When the bolt is pushed forward, it moves a pellet from the magazine into the chamber. After firing, drawing the bolt back to cock the rifle allows the spring loaded pellet holder to rotate to bring another pellet in line with the chamber. Closing the bolt the moves the pellet forward into the chamber.

Filling the reservoir of the Marauder to achieve a high pressure requires a special pump or a scuba tank. It is reasonable that one would be willing to expend some effort for a friend. However, when the reservoir is fully charged, it is possible to fire 25-30 shots at full power.

The Marauder is an imposing air rifle. Physically, it is 43 inches long and weighs 7.5 pounds. Because it is furnished with no open sights, it is necessary to mount a scope on the rifle which can raise the weight to as much as 8.5 or 9 pounds. Because the reservoir tube must be contained within the forearm, the stock is thick. The stock is equipped with a large rollover cheek piece so the rear section of the stock is quite thick also. Both the shrouded barrel and the reservoir tube are rather large, and they are mated to a massive metal receiver. So, my initial perception was that the Marauder was a large air rifle.

A complete description of all of the important features of the Marauder is a considerable task. As a result, I will stress only some of the major attributes that make this such a capable and versatile air rifle. One of these features is the choked barrel. By having the bore slightly smaller near the muzzle, the skirt section of the pellet is given a uniform size and shape just before it exits from the muzzle which increases accuracy. Trigger action of the Marauder is outstanding. There is a light take up motion then crisp let off with a pull of about two pounds on my rifle. Another outstand feature of the Marauder is that it can be tuned for optimal velocity with a particular pellet. For example, if it is found that Crosman Premiers give best accuracy when the velocity is 850 ft/sec, it is possible to tune the rifle to give that velocity.

Although the Marauder is a very powerful air rifle, it is exceptionally quiet as is illustrated by an event that occurred during testing. While I was shooting the Marauder, another shooter arrived at the range to practice for an event known as a plate shoot with his center fire pistol. As he came over to where I was shooting, he put on his hearing protectors. I told him that they were not needed, but he took one look at that boss airgun and would not believe me. He said that he had a $5,000 hearing aid and was not going to take any chance with a loud gun. I assured that with the hearing loss I had suffered over the years that I was not about to shoot a loud gun without hearing protectors. At that time, I fired a pellet at the target. The other shooter simply could not believe that such an imposing airgun could be that quiet! Yes, the Marauder is unbelievably quiet for such a high powered airgun.

In the testing that I did, I made sure that the pressure was in the range 2,200-2,800 psi. Because a PCP discharges only air, there is no noticeable recoil. Therefore, it was easy to control the rifle during firing. Although the Marauder is a large air rifle, rests on the sandbags very well when firing from a bench. I mounted a 3-9X AO scope on the rifle for testing.

I always test powerful air rifles at 25 yards in keeping with their being useful pest control tools. With Crosman Premier pellets, by first 5-shot group measured only 0.56 inch. Firing additional groups result in an average size of only 0.44 inch for five groups with the smallest being a ragged hole of 0.24 inch. For an outdoor range where there is always some breeze, this is outstanding accuracy.

The Crosman pointed pellet has always been a favorite of mine. With that pellet, the average of five 5-shot groups was 0.61 inch. Testing with other pellets gave similar results so there is no doubting the accuracy potential of the Marauder. During all the test firing, there was never any failure to feed and functioning was flawless. There is no doubting the reliability of the Marauder. Velocity measurements showed that the Marauder gave 900 ft/sec with both Premier and wadcutter pellets. This corresponds to a muzzle energy of about 26 ft lbs which means that the Marauder has plenty of power for taking pests and small game even out to 50 yards. I would not call it a sleek rifle, but it sure had the qualities that endear it to a serious shooter.

After getting past my first impressions, I found the Marauder to be a wonderful companion whether at the shooting bench or sitting in the woods. It has all the attributes of a true friend, and the Marauder and I are destined to spend a lot of quality time together.

Jim House

Benjamin Marauder: Your mileage may vary

Friday, June 5th, 2009

Crosman recently released our new Marauder PCP gun, and one of the features that make it different from its predecessor, the Discovery, is its adjustability. In fact it is probably the most adjustable PCP gun on the market. This also makes it one of the most versatile guns. Its adjustable hammer energy and valve transfer port allow the gun to operate at fill pressures between 2,000 and 3,000 psi, and at various velocities. Due to these inherent features we are often asked about making adjustments for various shooting purposes. Our own factory sponsored team of Ray and Hans Apelles have a very in depth adjustment procedure that is a must read. It can be found here:
A-Team Tuning Procedure

This July a number of Crosman employees will be participating in a Field Target shoot in Binghamton, New York NERFTC. As that date is rapidly approaching, I started to consider what equipment to bring. That naturally got me thinking about how best to set up our new Marauder for optimum performance for long distance shooting.

Let me first preface this by saying I should not be confused with an expert in any shooting discipline in general, and field target in particular (that is why we worked with Hans and Ray Apelles on this project). I am also not the Engineer that designed the Marauder (that’s Russ), or the Premier Pellet (that of course, was Bob Holtz). I am just lucky to have worked with them all. Furthermore, I am not claiming that these velocity profiles are the best that can be achieved or that if you dial your gun in at the same setting you will get the same results. Your mileage may vary. This is just my opinion and thought process as I got my gun ready to shoot this match. I do hope this helps to illustrate

Here are some adjustment options and how I document them:

  • What I am labeling “Hammer Tension” the manual calls “Hammer Spring Pre-load adjuster” and for shorthand, I label “H”. When I say ”6 H”, I mean that the hammer adjustment is six revolutions in (clockwise) from the minimum starting point of completely (counterclockwise) out.
  • “Stroke Adjustment” is what the manual calls “adjusting the striker” or “hammer stroke” and I am using “S” as my shorthand. So “2.5 S” is shorthand for when you have the stroke adjusted two and a half revolutions in (clockwise) from the maximum starting point of completely (counterclockwise) out.
  • The “Transfer Port Adjustment” is what the manual calls the “metering screw” and I am using “V” as short hand (for velocity or “venturi “). The starting point is all the way (clockwise) in.

Starting point:
First off you should always document your starting point as a base line. If for no other reason than to make sure you can get back to the factory settings. The Marauder (as shipped in .177 cal.) has a velocity profile that starts at 2500 PSI and ends around 2000 PSI, and when shooting 10.5 grain Premiers, will usually average around 853 over 30 shots. We felt this was the best compromise for shooters that could be using a hand pump or a scuba tank to fill the gun. The velocity was also reasonably high enough for longer distances, while still getting a shot count of 30. The gun has a 10 shot magazine, and I like to think in multiples of 10 for shot count when looking at possible combinations.

Marauder Tuning Chart

Caliber – 177
Grains – 10.5
Hammer Tension (H) – 3
Stroke Adjustment (S) – 2.0
PSI Fill- 2500
PSI End – 2000
Pumps to Recharge – 44
Transfer Port Adjustment (V) – 2
Minimum Velocity- 837
Maximum Velocity- 862
Average Velocity – 853
Median Velocity – 855
Standard Deviation – 7.20
Extreme Spread – 25
Average FTLBS – 17.0
Cumulative FTLBs – 509.1
# Shots – 30
# of pumps per shot – 1.5
Foot pounds per pump (FtripleP) – 11.6

Faster is better
First I wanted to see the highest velocity I could achieve so as to get the flattest trajectory. I used the 10.5 grain Crosman premier heavy (CPH), as I have had the best results with them in this gun.

Marauder Chart

Caliber – .177
Grains – 10.5
Hammer Tension (H) – 6
Stroke Adjustment (S) – 0.0
PSI Fill – 3000
PSI End – 2200
Pumps to Recharge – 65
Transfer Port Adjustment (V) – 4
Minimum Velocity – 1007
Maximum Velocity – 1039
Average Velocity – 1025
Median Velocity – 1025
Standard Deviation – 9.32
Extreme Spread – 32
Average FTLBS – 24.5
Cumulative FTLBs – 490.0

# Shots – 20
# of pumps per shot – 3.3
# Foot pounds per pump (FtripleP) – 7.5

As you can see in order to get up to 25 foot pounds of energy (FPE), I needed to open the Transfer Port (V) out to max of four turns ( V 4). I also started at 3000 psi and had the longest stroke adjustment (S 0). The numbers I look at for longer range shooting try and keep the velocity spread under 30, the standard deviation under 9, and ideally below 5. I was a little high, but it was as close as I could get with this gun while keeping the other requirements.
Summary: This adjustment would give me plenty of power in case of a windy day, and also the least amount of drop at the 55 yard line. The down side is that the accuracy at this velocity may not be the best that it can be, Bob Holtz used 800 fps to do all his accuracy testing when he developed the Premier pellet. On a more a practical standpoint, I don’t want to have to count on having 3000 psi to fill the gun. If I was hand pumping, it would be too much like work. Most important was that most clubs limit you to around 20 FPE to reduce target damage, so I had to rethink my requirements.

Accuracy is king
My next idea was that if 800 fps was the most accurate velocity, I could probably get 40 good shots and keep in just under 12 FPE needed to shoot with the big boys in International Class.
I also wanted to bring the fill pressure down so that I wouldn’t have to pump as hard. To go under 12 foot pounds I would also change pellets to the Crosman Premier Lites (CPL).

Marauder Tuning Chart

Caliber- 177
Grains- 7.9
Hammer Tension (H)- 4.5
Stroke Adjustment (S)- 6.8
PSI Fill- 2150
PSI End- 1800
Pumps to Recharge – 28
Transfer Port Adjustment (V) – 1.5
Minimum Velocity – 797
Maximum Velocity – 824
Average Velocity – 813
Median Velocity – 814
Standard Deviation – 6.98
Extreme Spread – 27
Average FTLBs – 11.6
Cumulative FTLBs – 463.9

# Shots – 40
# of pumps per shot – 0.7
Foot pounds per pump (FtripleP) – 16.6

So to get the power level down, I turned the metering screw way down to 1.5 V, and backed off on the hammer energy by turning the Stroke in, to almost 7 S. The fill pressure of 2150 seems a little odd, but I just marked the gauge on the gun and filled to that mark.

Summary: I hit the velocity spread and standard deviation numbers that I wanted. I liked the number of shots per fill and it was easy to pump at this pressure. Reality was starting to set in when I considered how much Kentucky windage I was going to have to use. I was not really that good a shot when you consider that I was going to be shooting unsupported in the sitting position. I need all the advantages I can get if I’m not going to use shooting sticks like I did in Hunter class.

Compromise
The one thing I liked the most was the lower fill pressure so I decided what I wanted was exactly a 2000 psi fill for a starting point. That way I could use one of our 72 cc bottles (add link) and not have to worry about overfilling. Also, I wanted to go back to using the CPH and be at around the factory setting of 850 fps with at least 30 shots.

Marauder Tuning Chart

Caliber – 177
Grains – 10.5
Hammer Tension (H) – 4
Stroke Adjustment (S) – 6.0
PSI Fill – 2000
PSI End – 1655
Pumps to Recharge – 48
Transfer Port Adjustment (V) – 1.75
Minimum Velocity – 822
Maximum Velocity – 856
Average Velocity – 841
Median Velocity – 842
Standard Deviation – 9.27
Extreme Spread – 34
Average FTLBS – 16.5
Cumulative FTLBs – 494.8

# Shots – 30
# of pumps per shot – 1.7
Foot pounds per pump (FtripleP) – 10.3

I did this by opening up the transfer port adjustment to a 1.75 V and with a few hammer adjustments I was in the ball park.

Summary: Close, but not there yet. Unfortunately there was too much velocity variation. I would have to give up some of the shot count.

Fine tuning
Normally when I am trying to get a flatter velocity profile, I decrease transfer port diameter by turning the metering screw (V) in. On this gun it worked out to be the opposite. This just shows that sometimes it is best to make small adjustments and have patience (and a lot of pellets). With a little bit of trial and error, this is what I finally settled on.

Marauder Tuning Chart

Caliber – 177
Grains- 10.5
Hammer Tension (H) – 2.25
Stroke Adjustment (S) – 4.3
PSI Fill – 2000
PSI End – 1655
Pumps to Recharge – 33
Transfer Port Adjustment (V) – 2.125
Minimum Velocity – 840
Maximum Velocity – 857
Average Velocity – 850
Median Velocity – 851
Standard Deviation – 4.76
Extreme Spread – 17
Average FTLBS – 16.8
Cumulative FTLBs – 337.0

# Shots – 20
# of pumps per shot – 1.7
# Foot pounds per pump (FtripleP) – 10.2

If you look back up at the factory settings, you will see that they are not that different. I had come full circle. All I really needed to do was reduce the Stoke to 6.25 S and that would have reduced the hammer energy enough to bring my fill pressure down. This is a good place to point out that if you are having trouble getting the results you want, try increasing (or decreasing) your fill pressure to find the range that works best for you.

Summary: I found the velocity that I wanted and most importantly it was consistent. As I am going to be using the small bottle, it won’t be that much of problem to fill after only 20 shots, and with a 350 psi band of air I am able to get a dozen gun fills from one bottle fill (240 shots). Give it a try and let us know what you think.

Second option

I was happy with the results with the last test, but I decided that I should also see how the gun would shoot at 20 FPE. At this point I was getting the hang of this process and I know that since I had the hammer tuned for the current fill pressure all I should have to do in open up the V adjustment. I set the fill pressure around 1900 psi and adjusted the V screw out until I had a little over 900 fps.

Here is my Chart…

Marauder Tuning Chart

Caliber – 177
Grains – 10.5
Hammer Tension (H) – 2.25
Stroke Adjustment (S) – 4.3
PSI Fill – 2000
PSI End – 1655
Pumps to Recharge – 33
Transfer Port Adjustment (V) – 3
Minimum Velocity – 901
Maximum Velocity – 923
Average Velocity – 913
Median Velocity – 915
Standard Deviation – 7.10
Extreme Spread – 22
Average FTLBS – 19.4
Cumulative FTLBs – 388.8
# Shots – 20
# of pumps per shot – 1.7
#Foot pounds per pump (FtripleP) - 11.8

Summary: The velocity is not as flat as the last one, but acceptable and I have the added advantage of a little more power. Next step is to set up a scope and get out to the range and see what setting shoots best.

Give it a try and let us know what you think.

Ed

Warning: Please read your owner’s manual for safe operation of the Marauder, as well as the instructions for making these adjustments. In order to properly make these adjustments, a certain level of familiarly with the fundamentals of a Pre-Charged Pneumatics (PCP) gun is assumed. If you are not comfortable with the procedures talked about here and in the manual, please seek the assistance of a professional Air Gun Smith.