Gen 2 .25-caliber Benjamin Marauder: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

Benjamin Marauder air rifle Gen 2Second-generation Benjamin Marauder in a synthetic stock.

Part 2
Part 3
Part 4

This report covers:

  • Introduction
  • RAI modular stock
  • Leapers parts
  • New Leapers scope
  • Past Marauder reports
  • Why this project?
  • Adjustments
  • Trigger
  • Power
  • The basics


This is the beginning of a very long test series. I’ve just purchased a second-generation Benjamin Marauder in .25 caliber for several reasons. First, I have read in so many places that the .25-caliber second-generation rifle is extremely accurate. It has a Green Mountain barrel that many people say is the bomb. I have tested the first-generation Marauder in .25 caliber and found it to be a very nice PCP that will reliably produce one-inch 10-shot groups at 50 yards. While that’s good, it’s not exactly what I would call the bomb, so I want to see if there’s a difference with this second-generation gun.

RAI modular stock

I also want to mount the Marauder in a modular stock from R. Arms Innovations. I saw that stock at the 2015 Malvern airgun show in April and made arrangements with Dave Rensing to get one for this test.

RAI modular stock
R. Arms Innovations modular stock for the second-generation Benjamin Marauder.

Leapers parts

There are a lot of UTG parts that go on that stock that Leapers has provided for this test. The modular stock calls for them, and some are very exotic — namely, the folding butt. I’ll cover all of those parts in detail when I mount them on the modular stock.

New Leapers scope

Leapers also sent me one of their brand-new UTG Accushot 2-16×44 Tactical scopes for this project. Yes — I did say 2 to 16 power! I showed you this scope in the 2015 SHOT Show report (see Day 2) and mentioned that Leapers also has a new 1-8x and a 3.5-28x that will be out this year. The 2-16x is hitting the market right now, and Pyramyd Air will have them in stock very soon.

For those who are new to the shooting sports, a variable scope with 8x magnification ratio is very special. The cheapest 1-8x scope until now has cost over $1,500. Leapers already sells their UTG Accushot 1-8×28 CQB for a fraction of that.

There are now other 2-16x and 3-28x scopes coming on the market, but they carry very stiff pricetags. Those who know Leapers know they won’t put their name on a scope until it’s exactly what they want it to be. So, this is the chance to be able to purchase an exotic telescopic sight that was, until recently, out of reach for most people.

Past Marauder reports

I’ve done a lot of reports on Benjamin Marauders over the years. I thought this would be a good place to list links to all of them, so you can go back and reference if you want. Here they are:

Benjamin Marauder .177 caliber: Part 1
Benjamin Marauder .177 caliber: Part 2
Secrets of loading the Benjamin Marauder magazine
Benjamin Marauder .177 caliber: Part 3
Benjamin Marauder .177 caliber: Part 4
Benjamin Marauder .177 caliber: Part 5
Benjamin Marauder .177 caliber: Part 6
Fixing a Marauder magazine
Benjamin Marauder .177 caliber: Part 7
Benjamin Marauder .25 caliber: Part 1
Benjamin Marauder .25 caliber: Part 2
Benjamin Marauder .25 caliber: Part 3
Benjamin Marauder .25 caliber: Part 4
Benjamin Marauder .22 repeater with synthetic stock: Part 1
Benjamin Marauder .22 repeater with synthetic stock: Part 2
Benjamin Marauder .22 repeater with synthetic stock: Part 3
Benjamin Marauder .22 repeater with synthetic stock: Part 4
Benjamin Marauder .22 repeater with synthetic stock: Part 5

Why this project?

Clearly, I’ve written a lot about Benjamin Marauders. So, why this project? Well, while I’ve written about the gun, I’ve never had the opportunity to modify one and make it my own. I’ve always been testing them as they came from the factory, with whatever adjustments the gun allows — which is a lot. This time, I’m going to take control of the rifle and really wring it out. I want to test that RAI modular stock because it seems so small and slim — although I have to admit the synthetic stock the Gen 2 Marauder comes with is pretty slim and svelte already.

Compared to the old wood-stocked Gen 1 Marauder, this one is a full pound lighter. And when you shoulder the rifle, you notice how slim the forearm feels, compared to the thick wood stock on the Gen 1 rifles.

I really wanted to test that Green Mountain barrel that I see so many people bragging about. I know that Crosman rifles the .177- and .22-caliber barrels in-house, and you can read my reports linked above to see the accuracy I’ve extracted from this airgun. Regardless of caliber, it always seems to hover around one inch for 10 shots at 50 yards. That’s pretty good, but it isn’t as good as what I hear people bragging about. So, this test will be seriously focused on accuracy.


I’ve already written volumes about the Marauder trigger, the fill-pressure adjustment and power adjustment. I expect this rifle to act the same as the others I’ve tested, which is to say it will be very flexible and tunable. Will I be able to get it to the level of perfection I’m seeking — the level others have written about on various chat forums? We shall see.

I’m going to run this test a little differently. I’ll combine Parts 1, 2 and 3 in this report and the next as I sort out the rifle, adjust the trigger, mount the scope, adjust the stock and set the power where I want it. Past reports described it pretty well, so I’ll borrow from them.


The trigger was set very heavy with a lot of creep in the second stage as the rifle came from the box. I lightened the trigger-pull adjustment as far as it will go and then worked on the stage-1 and stage-2 adjustments. When I finished adjusting, I had the trigger breaking at 1 lb., 1 oz. with a crisp second stage that has no creep. I bumped the rifle several times, and the sear didn’t release.

Benjamin Marauder synthetic stock trigger adjustment screws
The large round screw at the left adjusts the trigger-pull weight. Behind the trigger blade, the two small screws adjust the first- and second-stage pull length. And the screw behind those 2 allows for slight repositioning of the trigger blade.


I’m going to leave the power adjustments where they are until I shoot some groups at 50 yards. No sense changing something before I know how well it performs. Unlike the trigger, which is a matter of personal preference, I can’t tell anything about accuracy without shooting the rifle at targets.

The basics

I’ll close this report with the basic description of the Marauder I’m testing. It’s a .25-caliber 8-shot precharged pneumatic repeater. It comes with one magazine and may or may not come with a degasser tool included. The rifle accepts up to a 3,000 psi fill of air, but that level is adjustable by the owner. You can also operate the Marauder on CO2, if you prefer.

The rifle weighs 7.3 lbs., but it comes without sights. A scope and mounts will add another pound or more to that, and I’ll install a UTG bipod, which adds another pound. My rifle will tip the scales around 10 lbs. once everything is installed.

My Marauder has a black synthetic stock that I’ll use for the initial tests. At some point, I’ll install the new RAI modular stock with folding butt. I don’t know what that will do to the weight, but I’ll keep you informed.

The barrel is inside a baffled shroud, so the report is much quieter than it would be if the muzzle was exposed. While this isn’t a super-quiet airgun (I’ve already fired it many times), it’s very quiet for what it is — referring to the caliber and the power level.

There are links to 18 past reports if you want to know more about Marauders in general. For how this one performs, you will have to wait and see, just like me.

Walther Terrus air rifle: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3

Walther Terrus
Walther’s Terrus rifle with synthetic stock.

This report covers:

  • Open sight test
  • Different artillery hold
  • Cleaned the barrel
  • Mounted the scope
  • First shot — lost my aim point!
  • Crosman Premier pellets
  • RWS Meisterkugeln pellets
  • Overall evaluation

Today, I’m scoping the .22-caliber Walther Terrus and shooting it at 25 yards. This is an air rifle for which I have high hopes because it has many great features we have already seen, and the price is as good as it gets. If the Terrus is accurate on top of everything else, we’ll have another world-beater.

Open sight test

In part 3, we shot the Terrus with its open sights at 25 yards. I knew I wasn’t going to be as accurate with open sights, but I’d hoped the rifle would encourage me. I don’t think it did, though. My open-sight groups were close to 2 inches or more, though a couple did have some promising clusters. I wondered how much better it would get with a scope.

Different artillery hold

A couple readers advised me to slide my off hand forward instead of touching the triggerguard. I mentioned that the stock swell at the forearm was a problem, but on today’s shooting I did exactly that. This is an alternative artillery hold that sometimes yields good results. It felt odd because of the stock swell, but I was able to do it. My off hand was at the rear of the cocking slot.

Cleaned the barrel

I cleaned the barrel with J-B Non-Embedding Bore Cleaning Compound simply because several readers suggested it. When I did, I discovered that the test rifle has an extremely tight bore. Extremely tight! I used a worn brass brush and still had difficulty getting it through the barrel. But it was possible to pull the brush through several times, so that’s what I did. Then, I removed all the residue and got ready for the test.

Mounted the scope

I selected a Leapers UTG 8-32X56 AO Accushot SWAT scope with sidewheel parallax adjustment. The exact scope I used is no longer listed, but I linked to the closest scope that’s still being sold. This big scope is too much for a Terrus; but when I’m pressed for time, I go with what’s the most ready. This scope had 2-piece BKL high rings already attached, so it was quick to mount to the rifle. And I lucked out a second time when the Terrus proved to NOT droop! I set the scope to 22x which looked good.

Sight-in was a single shot at 12 feet; and then I backed up to 25 yards, where it took 6 more rounds to get on target. Just this one time, I decided to adjust the scope to strike the center of the target. There are some people who think where you are on the bull is important, and I wanted to satisfy them.

First shot — lost my aim point!

And the first shot was a near-pinwheel (center of the bull blown away)! There went my aim point! But I guesstimated where it was and shot 10 13.43-grain JSB Exact RS pellets into a 0.636-inch group. I thought I noticed a small amount of twitchiness in the hold, but it wasn’t bad.

Walther Terrus JSB group 1
At 25 yards, the Walther Terrus put 10 pellets into 0.636 inches. Not bad for shooting 9 of them without an aim point!

On the heels of the good performance from the Diana 340 N-TEC the other day, I decided to give the Terrus a try rested on the bag. This time, 10 went into 0.579 inches — making the Terrus a neutral rifle that’s not hold-sensitive! I did not discover this during the test, though. I thought the second group was slightly larger than the first, so the rest of the test was shot with the artillery hold.

Notice that this second group has shifted slightly to the left. Just the manner of the rest or hold made that difference. All targets were shot with the same scope setting.

Walther Terrus JSB group 2
At 25 yards, the bag-rested Walther Terrus put 10 pellets into 0.579 inches. This is a good pellet for this rifle!

Crosman Premier pellets

I also tried some Crosman Premiers. I stopped after just 5 shots, because the group had already grown to 1.422 inches. The Premier is obviously not suited to the Terrus.

Walther Terrus Premier group
At 25 yards, 5 Crosman Premiers went into 1.422 inches, so I stopped shooting. This isn’t the right pellet. And the pellets landed in order — at the low right, center of the bull, low left and the last 2 low right.

RWS Meisterkugeln pellets

While wadcutter pellets aren’t good for long range, they’ll sometimes do well out to 25 yards. I had an unopened tin of RWS Meisterkugelns, and the power of the Terrus seemed well-suited to their 14-grain weight, so I went for it. When the first 8 pellets landed in a tight 0.578 inch cluster I thought I was on to something; but on shot 9, I didn’t fully relax and the shot landed high. I call that one a pulled shot; but on the last shot, I did everything perfect and it went into the same hole as pellet 9. So, the Meisterkugeln pellets are slightly twitchy. Ten shots in 1.197 inches at 25 yards.

Walther Terrus Meisterkugeln group
At 25 yards the first 8 RWS Meisterkugeln pellets went into 0.578 inches. Shots 9 and 10 opened the group to 1.197 inches.

Overall evaluation

There is no longer any doubt — the Walther Terrus is a world-beater! You get a lot of value in a very low-priced package. I would recommend getting the wood stock to avoid the swollen forearm on the synthetic model; but if money is tight, you can learn to live with it.

The trigger is nice, but I think it could be improved. I’d like the release to be a little lighter. The breech lockup cannot be improved — it’s perfect right now. The open sights are throwaways, in my opinion; and with the accuracy we see today, I think most of you will want to mount a scope.

The rifle still buzzes a little when it fires, but I’m going to see what I can do about that. I’ve decided to make the Terrus a project rifle, so I bought it yesterday from Pyramyd Air. The fun ain’t over yet!

Odds ‘n’ ends

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • The artillery hold
  • Who makes it?
  • Does it have a Lothar Walther barrel?
  • Strange questions
  • Passion
  • More in me

Today, I’m taking time to address some of the many things that I want to talk about that don’t add up to a whole report by themselves. I’ve wanted to do this for several years and never took the time to do it, but today I’m just going to do it.

The artillery hold

If you don’t know what the artillery hold is, please read this and watch the short video. Blog reader Chris USA asked me how I approach shooting spring guns. He assumed I started with a firm hold and then went to the artillery hold when that didn’t work. I don’t. I start with the artillery hold first; because over the past 20 years, I’ve leaned that most recoiling spring guns need it.

But in recent years, I’ve also discovered that the number of springers that don’t have to be held that way is larger than I had assumed. I think I can boil it down for you this way. When a spring gun seems to scatter its shots unless you pay careful attention to the hold, you have to use the artillery hold. But when a spring gun seems to want to put all the pellets in the same place, that’s one that can probably be rested directly on a bag.

Until I shot the Diana 340 N-TEC in yesterday’s test, I would have told you that only smooth-shooting low-powered guns would do that. But the 340 disproved that. It’s smooth, even at great power, which is why I tried it on the bag.

I still don’t know everything, despite what you may have have heard. Like all of you, I’m still learning this stuff as I go. Whenever you find a stable springer, try resting it on the bag. The artillery hold is a wonderful technique, but it isn’t always needed.

Who makes it?

In recent years, people have become obsessed with the origins of airguns. I guess the Diana situation is a good illustration. One person wants only a Diana-made airgun because he insists that only German-made airguns are worthwhile. The next person wants a Diana that has been made in Rastatt, before the company was moved by the new owners. Then there’s a guy who doesn’t want a Diana at all. He wants the Chinese copy made by Factory Number 2, because they make a product that’s just as good as Diana, but they don’t charge an exorbitant price for it. A fourth fellow then chimes in and tells us that the White Stag company is copying the rifle made by Factory Number 2 and giving it a superior trigger. And, finally, a guy asks why Diana doesn’t just copy the rifle Factory Number 2 builds, and give it the White Stag trigger?

Folks, this stuff is gettin’ too heavy for my head! I just test them and report what I find. You have to sort them out yourselves.

Does it have a Lothar Walther barrel?

Close on the heels of who makes the gun comes the question, “Who makes the barrel?” As if only one company in all the world knows how to make airgun barrels. Then, I see comments about why certain airguns are so accurate. They all seem to say that it’s due to their Lothar Walther barrels. I keep my mouth shut when this happens, even though I know some of those guns people are bragging about use barrels made by Anschütz and even BSA. Heck — that’s where John Whiscombe went for his barrels!

Lothar Walther makes fine barrels, I will give them that. But so does Crosman. Yes, I said Crosman! I have seen Crosman barrels that will shoot just as well as anything Lothar Walther makes. There are two distinctions that separate Crosman barrels from Lothar Walther barrels. First — Crosman doesn’t put the effort into barrel-making that Lothar Walther does. That’s not a criticism of Crosman. They are simply making a lot more things than just barrels.

And second, Crosman is not known for their barrels. They should be, in my opinion, because they’ve made some darn fine barrels. But at the rate they manufacture airgun barrels, it’s impossible to hold the same level of consistency that Lothar Walther holds. You will pay 10 times as much (and a heck of a lot more, truth be told) for a Lothar Walther barrel as you will for a Crosman barrel, so there isn’t the time in the process to maintain the same level of consistency.

As far as I know Lothar Walther doesn’t make:

CO2 cartridges
Complete airguns

…and a great many other products. Each of these (pellets, BBs, CO2 cartridges and whole airguns) are entire industries, yet somehow Crosman manages to do all of them well, while still making good barrels.

If there’s a chink in their armor, it comes from the guns they don’t make — the guns they buy from Wang Po Industries, as blog reader RidgeRunner refers to them. I’ll agree, those guns are the Achilles Heel of the Crosman product line. They’re what they are — some are okay and others are not so good, but Crosman receives them in 40-foot containers and whatever comes out has to be disposed of, one way or another. But don’t tar the entire company with this one brush, because Crosman is still a leader among airgun manufacturers.

I think the globalization of airgun manufacture disturbs our conservative natures. We don’t all vote the same way, but when it comes to airguns and shooting, we have a lot more in common than most of us would care to admit.

Strange questions

I read every question this blog receives. Even though I don’t always answer them (I have no time), I read them all. Along with the regular questions, there are a few I find strange.

One that I get a couple times each year deals with using air pistols to kill pests. Now an AirForce TalonP air pistol can easily take small and even medium-sized game. It produces 50+ foot-pounds of energy at the muzzle. But a TalonP pistol doesn’t exactly fit in your pocket. It’s not a pistol in the same sense that a Walther PPK/S is. And that’s what these questions are asking: “Can I kill rattlesnakes with a Walther PPK/S BB gun?”

NO — you can’t!!!!!

Don’t even think of trying, because if the snake finds out what you’re trying to do (and they will), then it’s YOU who are in trouble.

Then there’s the guy who has disassembled his Rolex watch and wants me to provide step-by-step instructions and preferably a short video to help him assemble it again. Did I say Rolex watch? I’m sorry, it was his multi-pump pneumatic, but it might as well have been a Rolex.

Okay — here are the instructions. Set the parts of the airgun on the kitchen table. Raise your left hand and place your right hand over your heart and swear you will never take apart another airgun. The bill for this lesson is the cost of your now-destroyed airgun. If you want an advanced degree, pack as many of the parts as you can find into a box and ship them to a repair center like Pyramyd Air. That costs more, of course. Education always costs something.

“Well, heck, Tom — I could just not take the next one apart at all — just send it in for repairs when it needs them.”

See — you’re smarter already!

The final strange question is one I wrote. I never got one just like this, but I get a lot of them that are similar:

hello i have a airgun that my father got as a kid for me it worked until a few years ago then stopped one day it looks simple to take apart and i would like to learn to fix airguns as i am planning on starting a repair business when i retire next year what do you think is the best book to learn how to repair airguns and can you please tell me the schools that have airgun repair training programs

I don’t know what you want, because I could read these thoughts many ways. Please try to break up your thoughts into sentences so I give you the right advice.


I am passionate about the subject of airguns. But I don’t “hype” guns, like some new readers suppose. In fact, I do the opposite. An airgun has to please me before it gets my approval, and not too many do. Yesterday, you saw one in the Diana 340 N-TEC.

Just because I don’t mock certain manufacturers or use foul language, never suppose that I don’t care. My big fear is that people will act on my recommendations and be disappointed.

More in me

I’m sorry, but I needed to do this today. I guess I reached critical mass. There’s a lot more, but I promise to parcel it out in small amounts.

Diana 340 N-TEC Classic air rifle: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Diana N-TEC 340 Classic
Diana 340 N-TEC 340 air rifle

Part 1
Part 2
Part 3

This report covers:

  • Scoping a drooper
  • Firing cycle is smooth and quick
  • Trigger takes some learning
  • Artillery hold
  • First group
  • Second group
  • Third group
  • I was pleased!
  • Artillery hold abandoned — the fourth group
  • The bottom line

Boy, has this test turned out to be an eye opener! I had hoped that the Diana 340 N-TEC Classic would not disappoint, and believe me — it didn’t!

Scoping a drooper

Today, I’ll test the rifle scoped at 25 yards. I mounted an AirForce 4-16x scope in UTG Quick Lock Max Strength high Weaver rings; but this is a Diana air rifle, and that means the scope base on the rifle is proprietary. Knowing Diana’s reputation for drooper barrels, I also mounted a prototype UTG drooper scope base on the rifle. They aren’t supposed to fit, but this one did, perhaps because it’s a prototype and not the same as the bases they sell.

Even with the drooper base, the rifle still shot too low at 25 yards. The drooper base I chose has a shallow droop angle, so I think the 340 N-TEC either needs a drooper base with a steeper angle or an adjustable scope mount to compensate. At least, the rifle I’m testing needs that.

Firing cycle is smooth and quick

I’d forgotten how smooth and quick the firing cycle of the 340 N-TEC is. When the gun fires, it seems like the pellet is already at the target 75 feet away. The rifle is dead calm, like something that comes from a top tuner’s shop. And there’s no aggressive slap in the face from the cheekpiece like you get from most rifles with powerful gas springs. The shot is just solid, fast and pleasant — the way we expect spring rifles to be, although very few ever are.

Trigger takes some learning

The trigger, on the other hand, requires getting used to. It’s vague and light. The rifle fires before you’re ready. The best solution is not to touch the trigger until you’re ready to let the shot go.

Artillery hold

I used an artillery hold, with my off hand slid forward to the point that the rear of the cocking slot was touching my palm. This is a good hold for stability.

First group

After sighting-in the first group I fired was with JSB Exact Heavy 10.34-grain domes. I saw that they did well in the 10-meter test, and I felt they were a good pellet to begin with. Boy — was that an understatement! The first 10 pellets went into 0.492 inches at 25 yards! That may be the best group I’ve ever shot from a powerful gas-spring rifle at 25 yards. I can’t remember a better one.

Diana N-TEC 340 Classic JSB group 1
The Diana 340 N-TEC Classic put 10 JSB 10.34-grain domes in 0.492 inches at 25 yards on the first target.

I have to tell you that I was impressed by the way this rifle shot. It seemed to need very little in the way of special holding technique, and, where most gas-spring rifles would have scattered their shots into a one-inch pattern at 25 yards, this rifle seemed to want to stack one pellet on top of another. I got the feeling that this is a natural shooter — that rare airgun that just wants to put all the pellets into the same place. More testing would tell the story.

Second group

Next, I tried some H&N Baracuda with the 4.52mm heads. I have no good reason for choosing this pellet except I wanted to see how something different would do. Ten pellets went into 0.641 inches at 25 yards. That’s not as good as the JSBs, but it’s still not too shabby.

Diana N-TEC 340 Classic Baracuda group
Ten H&N Baracudas Match pellets with 4.52mm heads went into this 0.641-inch group at 25 yards.

Like the first group, I was getting the sensation that this rifle wanted to put every pellet where it was aimed. Although the pellets landed in a larger group, none of them surprised me by flying erratically, the way pellets from powerful gas-spring rifles often do. I was starting to realize that the 340 N-TEC is a very stable air rifle.

I thought I would shoot just one more group of JSB pellets. This time there would be no excuses. I would hold each shot perfectly.

Third group

And that’s exactly what I did. The second group was also small, at 0.544 inches between centers. That’s slightly bigger than the first group, although the difference is so small that it could just be a measurement error. I’d obviously reached my limit with this rifle and pellet.

Diana N-TEC 340 Classic JSB group 3
Ten JSB Exact Heavy pellets made this 0.544-inch group at 25 yards the second time around.

I was pleased!

This is the first time in all my years of testing airguns that I’ve shot a powerful gas-spring rifle that is also neutral to hold. I knew the lower-powered gas-spring guns were pretty forgiving, but not the magnums — which the 340 N-TEC certainly is.

And that’s when I got a crazy idea. What if this rifle is so neutral that it’ll even shoot when rested directly on a sandbag? As in, no artillery hold?  Is such a thing possible? Until this test, I would not have thought so. But this 340 N-TEC acts like it wants to shoot, so I gave it a try.

Artillery hold abandoned — the fourth group

Lo and behold, I put 11 shots — not 10, but 11 — into 0.732 inches at 25 yards, with the rifle rested directly on the sandbag. I miscounted the shots, which is where the extra shot came from. This is the powerful spring rifle many of you said you wanted — one that’s neutral to hold. Well, here it is! And it’s powerful, relatively easy to cock (for a powerful gas-spring rifle, that is) and it has a light trigger.

Diana N-TEC 340 Classic JSB group 3
Eleven JSB Exact Heavy pellets made this 0.732-inch group at 25 yards the second time around. I miscounted the shots.

My complaints are few. First, the trigger is too vague. It certainly doesn’t perform like a Diana T06 trigger. But look at the groups I was able to shoot. Obviously, you can do good work with this trigger.

Second, I don’t like the excessive barrel droop. You have to plan on that going in. Otherwise, the 340 N-TEC is a world-beater.

The bottom line

I’m so glad I selected the least expensive 340 N-TEC to test for you. This is an affordable gas-spring hunting rifle that’s within reach of a lot of airgunners. If you haven’t made the switch to pneumatic rifles yet because you’re holding out hope that a good springer will come along — here it is. I don’t know that every 340 N-TEC will be as good as the one I tested, but I’m guessing this one is representative. Good on ya, Diana!

Air Arms S510 Ultimate Sporter: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

Today’s report is a guest blog from Pyramyd Air call center employee Tyler Patner, who’s going to tell you about the Air Arms S510 Ultimate Sporter.

If you’d like to write a guest post for this blog, please email me.

Okay, let’s look at this air rifle. Over to you, Tyler.

Air Arms S510 Ultimate Sporter
Air Arms S510 Ultimate Sporter

This report covers:

  • The stock
  • The forearm
  • Bipod
  • Finish
  • Chronograph results
  • Adjusting the gun for real-world operation

Air Arms has long been at the front of the pack when it comes to sporting air rifles. The year 2014 was no different for the iconic manufacturer. Celebrating their 30th anniversary, Air Arms rolled out several new models that caught the attention of airgunners the world over. The S410/510 series has been some of my personal favorites for quite some time. They represent a value for your money — for which you often have to pay at least a few hundred dollars more. Multi-shot, externally adjustable power, a great trigger and a highly accurate Lothar Walther barrel are all benchmarks of the line. The Ultimate Sporter represents a step forward for Air Arms. With the help of Minelli in Italy, they’ve kept the classic S510 style stock but made a few upgrades that both the obsessive field target shooter (yours truly) and any hunter can enjoy. Let’s now take a closer look at some of the features of the Ultimate Sporter.

The stock

The main difference most will notice on the Ultimate Sporter is the gorgeous laminated stock. With the introduction of the new Air Arms FTP 900 in the same year, Air Arms and Minelli presented a unique laminate color scheme that has not been seen on the production market before. Not only do the new colors add a bit of flare, but the addition of an adjustable cheekpiece marks the biggest upgrade that we’ve seen thus far over a standard S410/510.

Air Arms S510 Ultimate Sporter cheekpiece 1
The cheekpiece adjusts in several directions.

This is a feature many might overlook; but if you’ve never used a rifle with an adjustable cheekpiece, you really don’t know what you’re missing. When properly set up, it ensures a comfortable and consistent cheek weld that’s automatic and vertically and horizontally adjustable. You can also move it forward and backward and put some angle on it with the ball joint design.

Air Arms S510 Ultimate Sporter ball joint
The cheekpiece moves on an adjustable ball joint.

Air Arms S510 Ultimate Sporter cheekpiece 2
The buttpad also adjusts, making the rifle easy to adapt to most shooters’ physiques.

The forearm

Moving forward to the forearm, there’s a flat-bottom design unique to the Ultimate Sporter stock. It contains an accessory rail, the same as you’d find on a 10-meter target rifle or field target rig. Commonly referred to as an Anschütz or Euro rail, the gun comes standard with a swivel stud installed on the rail, which can be moved and even removed entirely. This matches the stud in the bottom of the cheekpiece rod and makes the rifle ready to accept a sling out of the box. For this review, I mounted an Air Arms bipod I found floating around.


I use a bipod on my FTP 900 and love the quick fold-out design. Sadly, this item is not imported at this time, but I wish it was! A UTG bipod could also be mounted to the swivel stud, as UTG provides a neat adapter for that exact purpose. This rail was previously found only on the field target lines from Air Arms, and I believe this was included in the Ultimate Sporter for the Hunter Field Target (HFT) shooters in the UK. With the introduction of the HFT 500 in late 2014, Air Arms made it very clear that this is the market for which the stock was built, as both rifles share the same stock.

Air Arms S510 Ultimate Sporter rail with bipod

The Air Arms bipod I attached to the rail isn’t currently sold separately by Pyramyd Air.


The Ultimate Sporter stock has a semi-gloss finish. When I first opened the box, I was taken aback by it because I was expecting the same high-gloss finish as the FTP 900. I’m not knocking the finish on the Ultimate Sporter; it’s just something that needs to be noted. The stippled sections of the stock feature the same rough feel that I experienced on the BSA Scorpion SE.  It looks like this is what Minelli is going with now, and I like it a lot. It provides a very responsive feel and great contrast to the smooth portions of this gorgeous laminated stock.

Air Arms S510 Ultimate Sporter finish difference
Though the wood laminate on the Air Arms FTP 900 stock is the same as the Ultimate Sporter, the finish is glossy compared to the Ultimate Sporter’s semi-gloss. That’s difficult to see in this picture, but you can readily see it in person.

Chronograph results

The beauty of a gun like the S510 is that you have an adjustable power wheel, which is an adjustment screw that lets you control the size of the transfer port. This makes chrony testing harder, as I had to play with different settings and record results.

Air Arms S510 Ultimate Sporter sidelever
The short sidelever is pulled out and back to retract the bolt. The silver knob is the right side of the power adjuster that’s controlled on the left side of the action.

To get constants for high and lower power, I used H&N Field Target Trophy pellets in the .22-caliber rifle I’m testing. At 14.66 grains, it gives me a good idea of how close to manufacturer specs the gun actually performs. With the power adjuster set to the lowest setting, I aired the gun up to 200 BAR and loaded up some FTT pellets. Over 53 shots, I got a high velocity of 658 f.p.s. and a low of 640 f.p.s. An 18 f.p.s. variation over that many shots for this unregulated gun is pretty phenomenal if you ask me. The 14.66-grain FTT pellets were pushing 13.70 foot-pounds of energy at the average velocity of 648 f.p.s. As velocity started to drop off, I checked the gauge and saw the gun was down to about 135 bar. I was seeing spreads of about 2 f.p.s. between shots, so I knew that as long as the barrel was a good one, this gun was going to be a shooter!

I refilled the gun and turned the adjuster all the way to the other end of the power spectrum to see how hot this baby could go! This time, I really got a clear sweet spot. I found that a 200-bar fill is too much pressure at this setting, as we find with most unregulated PCPs. This should be particularly good news to hand-pumpers and folks who only have 3000 psi scuba tanks. Not quite as many pumps and more useful fills from your tank is never a bad thing, unless you’re a glutton for punishment!  From a 200-bar fill, the first 15 shots were really useless. They started around 900 f.p.s., and it took the first 15 shots to get up to 960 f.p.s. before we got into the sweet spot. Those looking for the very best accuracy will find only inconvenient points of impact shifts over the course of those 15 shots. Once we passed shot 15, though, the numbers began to impress me.

Shots 16-32 gave an extreme spread of just 15 f.p.s., with a standard deviation of 2.80 f.p.s. That spot fell between 170 and 135 bar. If I were pumping, I’d far prefer going to 170 bar as opposed to 200 bar. Having used a pump in the past, I can tell you that my smaller frame can barely get a rifle up to 200 bar without jumping on the handle to force it back down! The highest recorded velocity was 973 f.p.s., and the low for those 17 shots came in at 958 f.p.s.

If we look at the entire shot string on the 200-bar fill, the low was 902 f.p.s. on the first shot. I stopped shooting once the velocity dropped below 930 fps, which happened at shot 40. Bear in mind that this is with the power adjuster set at the highest point. What it means is that the transfer port is fully open. So, this larger spread and lower shot count is to be expected. That’s all the adjuster is — a simple transfer port restrictor. With the transfer port all the way open, the 14.66-grain FTT pellet produced an average 30.30 foot-pounds over 40 shots. For a medium-weight, .22-caliber pellet like the FTT, that’s quite high. With a heavier pellet, such as the JSB 18.1 grain Exact Jumbo Heavy, you can expect to be in the 35-38 foot-pound range.

Adjusting the gun for real-world operation

Now came the task of finding out where the gun was most efficient for what I consider real-world numbers. This means using a heavier pellet and scaling back on the adjuster to get a tighter velocity spread. This also produces a smoother shot cycle. Before you tilt your head and give me that questioning look, let me explain.

When talking about a shot cycle, most people go straight to spring/gas-ram guns that have a lot of felt recoil. In a PCP, I’m talking about lock time as well as felt recoil. As you go up in power on a PCP rifle, you do begin to feel what I characterize as muzzle flip. This is a pulse created partially by the hammer (which in most hunting power PCPs is relatively heavy) hitting the valve, as well as the expulsion of air from the muzzle. Particularly with shrouded PCPs, you tend to feel this a bit more, as the air that gets caught by the baffles is propelled backwards into the dead space of the shroud. With the power adjuster on high, the shot cycle was ugly and harsh — I can’t describe it any other way. It’s not like the gun wasn’t accurate, but it took far more effort from me to achieve the groups I expected of a gun of this quality.

When shooting a PCP, I need the gun to do the work for me. Why? Well, I’m lazy and accustomed to 12 foot-pound field target guns that don’t move when you break the trigger. So, in my testing, I settled on the power adjuster set about three-fourths of the way toward the high end.

Air Arms S510 Ultimate Sporter power adjuster
The power adjuster (arrow) controls the size of the air transfer port. It’s located on the left side of the receiver.

With JSB 18.1 Exact Heavies, my string started at 825 f.p.s., with a 180-bar fill, peaked at 838 f.p.s. at shot 15, which was right around 150 bar. The string ended at 820 f.p.s. with shot 30. The pressure in the gun at the end was about 125 bar.

The JSB heavies produced roughly 28 foot-pounds at the muzzle. This is a pellet/speed combo with which I’ve had success in other guns, but I’ve only seen numbers this good out of regulated PCPs. Over the entire 30-shot string, the standard deviation was just 1.23 f.p.s., with an extreme spread of 18 f.p.s. This setup was yielding regulated results without the regulator! At this point, I wasn’t about to mess with the power adjuster further, as I don’t think those results could be bettered. The only thing left to do was shoot the S510 Ultimate Sporter for accuracy! I will do that for you in part 2.

An open letter to airgun designers

by Tom Gaylord
Writing as B.B. Pelletier

Announcement: Pyramyd Air has asked me to announce their Memorial Day Madness sale, which features some sizable price reductions.

This report covers:

  • Design parameters and constraints
  • Barrel
  • Pivot joint
  • Coiled steel spring items
  • Piston
  • Spring guides
  • Mainspring
  • Gas-spring items
  • Piston bore
  • Trigger and safety
  • Stock
  • Sights
  • Scope base
  • Disassembly
  • Discussion
  • You do the rest

I used to teach a subject called Value Engineering to Department of Defense procurement personnel. Value Engineering was a U.S. Army initiative from World War II, where a design was examined by not just engineers, but by all the disciplines that dealt with the product. The goal was to create the function of an item at the lowest cost.

They discovered, for example, that a maintenance man could make a small change that saved the Army millions of dollars by either making the item easier to maintain or making it so it didn’t require maintenance at all. On the other hand, a production manager might make a change in the design that dropped the cost to produce the item from $2000 to $3.00 by simply changing the way it was produced.

What I’m going to do today is start a multidisciplinary design review of an inexpensive breakbarrel spring rifle — the most popular airgun sold in America today. Blog readers can participate through the comments. I can assure you of one thing — nearly all airgun manufacturers have at least one person reading this blog every day. So, let’s give them some food for thought.

Design parameters and constraints

  • The rifle we design has to cost very little to manufacture. Nothing that costs extra money will be included in the design.
  • We’re building a rifle for the broadest possible use. That means it must be accurate, easy to cock, easy to maintain, have a good trigger and good sights, and a stock that adapts to the broadest possible shooter base. Power will be secondary to all other constraints, but we won’t do anything to limit the power of the gun. It’ll be whatever it must be — in light of all aspects of design.
  • Fewer parts means a simpler design.
  • The broader the appeal, the more we’ll sell. The more that sell, the lower the development costs per gun.
  • Maintainability builds customer confidence.
  • Accuracy is the most important aspect.
  • Smoothness of the firing cycle takes precedence over everything except accuracy.


The rifle must have a good barrel, capable of producing good accuracy. That would be 10 shots grouping in less than one inch at 25 yards. We have learned in this blog that good barrels don’t have to cost a lot of money. Look at the accuracy we got from a thin-walled steel barrel in the $100 PCP — (read Part 4).

Because this is a springer, we can keep the barrel short. Ten inches is all that’s needed. That keeps the cost down, because short barrels take less time to rifle. The rest of the tube that appears to be the barrel can be hollow. We need the extra length for cocking and separation of the open sights.

The barrel needs to have a good, clean crown, so special attention will be paid to each crown produced. The barrel needs to be mounted solidly in the jacket or shroud so there’s no chance for movement.

Pivot joint

The pivot joint must be a bolt or other means of attachment whose tension can be adjusted when the barrel becomes loose. A locknut is required unless the pivot bolt can be designed to not loosen with use.

The pivot joint shall have a design that reduces friction to the maximum extent. Washers on either side of the baseblock are in common use for this today, but they’re not mandated.

Coiled steel spring items

The following items apply if a coiled steel mainspring is used in the design.


The piston must have a seal that’s easily replaceable when needed. The piston must also serve to guide the mainspring to reduce vibration. The piston stroke should be long to give maximum power with the lightest spring tension.

Spring guides

Some method of guiding the mainspring shall fit the mainspring tight to reduce friction. It should be incorporated into the design of the piston without adding additional parts.

Anti-spring torque

There shall be a means of eliminating the rotational torque from the mainspring at both ends. A plain washer is sufficient for this. The finish of the washer shall be as smooth as is economically feasible in a high-rate production scenario.


The mainspring shall be a strong yet light coiled wire spring. It should be under minimum load when at rest. Before installation, it shall be lubricated inside and out with a low-friction, high-viscosity grease.

Gas-spring items

If a gas spring is used, it should be very easy to cock. Use of a long piston stroke allows for lower gas pressure in the spring and also reduces the cocking effort through optimum cocking linkage design. The piston weight should be kept as low as feasible with longevity to reduce forward recoil with the shot.

Piston bore

This applies equally to steel mainspring and gas-spring guns. The piston bore size should be as small as possible to keep the overall size of the rifle in check. Use piston stroke rather than bore diameter to generate power.

Trigger and safety

A two-stage trigger with an adjustable first stage should be used. It should be possible to adjust out the first stage — making the trigger single-stage.

The trigger should work through geometric design (over-center release) rather than sear slippage. If a sear is used, sear contact should not be adjustable.

There should be a manual safety that blocks the trigger.


The stock should have an adjustable length of pull that ranges from 12-1/2 inches to 14-1/2-inches. The stock line should be as straight as possible, negating the need for an adjustable comb.


The sights should be adjustable in the rear and a hooded post on a ramp up front. The adjustments should have a means of determining where the rear sight notch is and where is is being adjusted. There shall be markings on the sight to indicate which direction to turn the adjustments to move the strike of the pellet.

Scope base

A Weaver-style scope base should be permanently attached to the spring tube.


The rifle shall be designed with ease of disassembly in mind. The mainspring will not be under great tension, so a mainspring compressor shall not be needed for this.


Try to apply any one of these design features to a rifle that’s currently being made, and you incur considerable cost. Therefore, this rifle must be designed from the ground up. Airgun companies today are fearful of a clean sheet of paper because of the engineering time they think it entails. However, if they would just hold a couple preliminary design reviews of these features, they would save thousands of man-hours by finding the simplest solutions to every feature.

This is a process in which you “make haste slowly,” as Benjamin Franklin once said. You put the descriptions of the features up on the walls of the conference room and let them soak into everyones’ pores over time. You don’t set deadlines in the beginning, like, “We want to roll this out at next year’s SHOT Show!” In the world of software design, there’s a saying: “You want it bad? It’s bad right now!”

The company comptroller is just as welcome to contribute as the lead engineer. Remember that actress Hedy Lamarr co-invented the spread spectrum and frequency hopping communications technology that was first used to control torpedoes in WWII. For her efforts, she was inducted into the Inventor’s Hall of Fame in 2014.

Avoid absolutes in the beginning. Saying the gun should retail for $175, or weigh 6 lbs. or achieve 900 f.p.s. in .177 caliber eliminates 98 percent of the design possibilities.

You do the rest

That’s my contribution. Now, you do your part and help design this spring rifle farther.

Hatsan BT65 QE: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4

Hatsan BT65 QE
Hatsan BT65 QE.

This report covers:

  • Eun Jin pellets
  • Predator Polymag pellets
  • JSB Exact King pellets
  • Bottom line

This is the final test of the Hatsan BT65 QE. I’ve enjoyed working with this rifle. Once I got the silencer issue sorted, the gun became quite accurate. Today, I’ll try some other pellets, and I’ll also try a group at 100 yards. The silencer parts are still out of the shroud, so there’s nothing to hinder the flight of each pellet.

Eun Jin pellets

I tried the 35.8-grain .25-caliber Eun Jin dome first. Because of the rotary magazine, I was concerned this long pellet might not fit, but it did. It fit fine. And it cycled through the action without a fault. But accuracy was a different story.

These pellets went everywhere except where they were aimed. Only 6 out of 9 stayed on the target paper I was using; but since I had a paper backer, I could judge that the whole group was something like 4 inches between centers of 9 shots at 50 yards. It’s not a pellet I would recommend for this rifle. Given their power, it would have been nice if these Eun Jin pellets were more accurate; but there are several other very accurate pellets to choose from, so it isn’t a deal-breaker.

Predator Polymag pellets

The Predator Polymag was a pellet I really wanted to try in the Hatsan. They’re surprisingly accurate on some powerful precharged rifles, so the BT65 was the ideal candidate for a test.  Five were pretty close, but all 9 of them went into a 1.403-inch group at 50 yards. While they aren’t bad, they aren’t especially good, either.

Hatsan BT65 QE Predator Polymag
Nine JSB Predator Polymag pellets went into 1.403 inches at 50 yards.

JSB Exact King pellets

Then, it was back to the pellets I know are the best in this rifle — the .25-caliber JSB Exact Kings. By this time, I’d screwed with the scope settings so much that the pellets were not hitting the point of aim. That’s good, because then I don’t destroy my aim point, but it’s bad when I want to hit something other than paper.

A dobsonfly (a large insect that some might call a dragonfly) landed on one of my targets, giving me a target of opportunity. But the scope was set up with the point of impact intentionally off, so I had to shoot 3 times to walk the pellets in. Amazingly, the insect remained still as this was done. I know it sensed at least one of the pellets zip through the paper next to it because it fluttered its wings a bit. Shot 4 landed smack on the large predator’s body and left a brown smear on the target.

I then shot a 9-shot group that measured 0.79 inches between centers and another 5-shot group that measured 0.578-inches between centers. Both of these were at 50 yards.

Hatsan BT65 QE JSB King 9 shots
Nine JSB Exact Kings on the first magazine after a fill went into 0.79 inches at 50 yards.

Hatsan BT65 QE JSB King 5 shots
Five JSB Exact Kings from the second magazine after a fill went into 0.578 inches at 50 yards.

So without further ado, I walked down to 100 yards and put up a target. When I got back to the firing line, I proceeded to put 9 JSB Kings into 1.687 inches. This group landed on the centerline of the scope, but I was elevating the reticle 4 mil-dots.

Hatsan BT65 QE JSB King 100 yards
Even at 100 yards, 9 JSB Kings from the first magazine after a fill still went onto 1.687 inches between centers.

Bottom line

The Hatsan BT65 is a worthy .25-caliber repeater. The one I tested had accuracy problems until I removed the silencer parts, clearing the path for the pellets. If I owned this rifle, I would simply enlarge a couple of the holes in the baffles and put the parts back in the shroud. I’ve fixed other PCPs this way, and I know how easy it is to do. But I don’t own this gun, so I left the parts as they were.

With the baffles installed, the rifle is certainly quiet. The report doesn’t give much indication of all the power that’s on tap.

Hatsan says the rifle is protected against double feeds — where 2 or more pellets are fed into the barrel. I found that to be true only when the rifle is carefully cocked. You have to pull the bolt handle all the way back like you mean it. It became second nature to cock it correctly after a while, but don’t think that a double feed can’t happen — because it can.

The accuracy is stunning! You get what you pay for as long as you stick with the right pellets.

The trigger is fine and adjustable. It’s a sporting trigger — not a match trigger, but you shouldn’t have any reason to complain about this one.

The bottom line is that the BT65 is a good air rifle that performs as intended. It’s worth your consideration.