Quackenbush Air Guns

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The .50-caliber Bandit!
A modern big bore air rifle priced for everyone

Story and photos by Tom Gaylord
Copyright 2003 Tom Gaylord

Dennis Quackenbush completed his first big bore air rifle in 1996. The Brigand, the first of his Outlaw series, was an astonishing gun when it was introduced, because there simply wasn't anything else that could be bought affordably. Since then, however, the big bore field has expanded so dramatically that Quackenbush has had to adapt to some pretty stiff competition. That has caused him to improve his designs until the CO2-powered Brigand of 1996 is now just a memory.

The Bandit is a .50-caliber rifle that shoots a 0.495 round lead ball weighing 182 grains. To optimize the new rifle for hunters, Dennis decided to look into the question of rifling twist rates and number of lands by actually testing different designs.

He started rifling barrels with different twist rates and different numbers of lands until he found one that offered the greatest combination of accuracy and performance. Contrary to the belief that a micro-grooved barrel is best for all airguns, it turned out that a SEVEN-groove tube with a fast twist rate (fast for round balls) works best for the Bandit.

As long as he was designing a new barrel, he didn't stop with just the rifling. He also choked the barrel at the muzzle. A smaller-diameter muzzle (the choke) removes most of the randomness of the bullet at the point of exit, which is the most critical spot in the barrel. We're used to choked bores on small-caliber air rifles, but they aren't common on big bores.

The Bandit is big. Not only is the bore size large, the barrel walls are also quite thick - especially for an air rifle that doesn't really need the strength of its barrel walls for safety. What it does need is stability to increase accuracy.

Many modern big bore airgun makers use seamless hydraulic tubing for their barrels. It's wonderful stuff and makes their job so much easier because they can buy it with a pretty straight hole already down the center. And it works, which is a good thing because it makes custom airgun barrels possible for lots of makers.

However, Dennis doesn't use hydraulic tubing. Since he can't buy tubing with the extra wall thickness he requires, he drills his barrels out of a solid bar of steel, then reams the bore smooth. He then cuts each groove separately. This method takes longer than pulling or pushing a "button" through the bore, but it gives Dennis the flexibility to change any of the dimensions of the bore at will.

This is really the old-fashioned way to make a barrel, and it takes a lot more time and care to do it this way. Drilling a straight deep hole through bar stock is a very challenging task, but Quackenbush has to do it to get what he wants.

In 2001, I asked Dennis to build an experimental .50-caliber Bandit with the longest barrel he could make to test my theory that a longer barrel will increase velocity in a precharged rifle. I knew from testing the 24-inch-barrel Bandit that some high-pressure air was exiting the muzzle behind the ball, and I wanted to use as much of it as possible.

It turned out that he was able to make a maximum barrel length of about 32 inches, so that was what I tested. The velocity increased by 59 feet per second (f.p.s.). Now, you might think that's not very much extra speed in return for the extra eight inches of barrel, and I would normally agree with you. But, when the ball weighs 182 grains and you are already pushing it 795 f.p.s., an extra 59 f.p.s. translates to another 39 foot-pounds. Now, that does mean something. It influenced Dennis to add two more inches to his production barrels.

Today's Bandit comes to you with a barrel of 26 inches, which delivers slightly more velocity and energy than before. The rifle weighs just under 8 pounds, depending on the density of the wood in each individual stock. The length of pull is 13-1/4 inches, and the overall length of the rifle is about 43 inches.

A ball-bearing detent on the bolt gives it a crisp final latch-up as it closes, and Dennis cuts a taper in his breech rifling so you don't have to force the large lead ball into the rifling with hand pressure. Small touches like these make the difference between a conversation piece and a good usable rifle.

The trigger is a simple but effective single-lever design. It creeps a bit, but it's manageable for a hunter. You can easily uncock the rifle by holding onto the cocking rod and slowly lowering the hammer to its resting point. The rifle has no safety, as such, so the simple uncocking procedure is a good one for owners to learn.

Most of the metal on the gun is blued steel, with just the hammer, bolt and cocking rod left bright. I am told these pieces will be made from stainless steel in the near future. Dennis offers several grades of metal polishing at graduated price increases, but I have always found his standard grade to be more than adequate.

The stock is American walnut. There have been several modifications to the shape of his stocks through the years. The new style has a taller cheek piece, which brings your eye up to a taller scope. You may find that your stock has a particularly beautiful grain and color pattern because these blanks were purchased from some of the top stock making companies in this country.

You probably won't want much magnification with a bore this large. I found the stock shape perfect for a vintage Beeman SS2 scope with integral mount. Speaking of scopes and mounts, the dovetailed rails on all Quackenbush big bore rifles are somewhat on the narrow side, so certain airgun mounts won't work. Also, Dennis has received some calls from owners claiming that their scope mounts were tipped to one side. This is invariably due to cheap mounts supplied with scopes. These cheapies have two different radii on their clamping bases, and the fatter side doesn't penetrate the Bandit's dovetail as deeply - resulting in a lean to one side. Fortunately, each rifle comes with a set of steel Bushnell rings that are split vertically. They have sharp points to engage the dovetails precisely on both sides of the receiver, and the vertical split in the rings ensures that every time you install them, they will be exactly centered with the receiver. What recoil there is in a Bandit is light enough that a stop is not needed.

The reservoir fill-port is up front. An integral sliding cover around the port protects the interior from dirt.

The port is sized as a five-sixteenth-inch hole. Dennis supplies a fill probe that will attach to any 1/8 British Standard Pipe (BSP) fitting, which is the most common fitting in precharged airguns.

The hanger that holds both barrel and reservoir at the front has three Allen screws that allow the muzzle to be repositioned. Any tendency to shoot to the left or right can be corrected that way without using the scope's internal adjustments.


The way this gun gulps air, you'll want to use a scuba tank to refill it most of the time. I found our test Bandit used 400-500 psi of air per shot for the first two shots. That begins to taper off starting with shot three. I felt that four good, powerful shots were available with each 3,000 psi fill. It's possible to get more than 10 shots from a fill, but the velocity of the final one will be down in the 400s. All big bores use a lot of air, which may surprise those who are used to getting 30-50 good shots from a smallbore PCP.

The vintage big bore guns from centuries past got more shots from an air charge than the new breed of screamers because they didn't do nearly the work with each shot. Big bore airguns of old were content to push out 60 to 150 foot-pounds of energy, with most of them hovering somewhere below 125 ft.-lbs. They derived their energy more from projectile weight than from velocity.

Today's big guns do both - they push big heavy bullets and they push them fast. Much faster than vintage airguns. The .50-caliber Bandit sends a 180+-grain ball downrange at a trifle more than 800 f.p.s., depending on the gun and the temperature. A vintage big bore of the same caliber might have gotten as high as 550 f.p.s. on a good day, but 500 would have been more like it. The difference between old and new might not seem like much, but it happens at a point on the performance curve where enormous energy is required to do just a little more work. The experimental long-barreled Bandit we tested went a little faster than the 26-inch standard model, but not enough to warrant an additional six inches of barrel.

Besides their barrels, modern big bores also use seamless hydraulic tubing for their pressure reservoirs, where the guns of the past used everything from bored steel cylinders to flasks made of folded iron with brazed seams. Today's guns work at pressures above 2,000 psi, while most vintage guns never went above 600 psi. This is one place where Dennis does use the tubing, simply because it is the best material available.

The reason vintage guns were able to do as much as they did with such limited air pressure was their combination of extra-long barrels and timed locks. Instead of the hammer just knocking the valve open by brute force, the timed lock opens it with a set of cams that hold it open for a specific length of time. This allows a larger charge of lower-pressure air to escape. The longer barrel increases the amount of time the lower-pressure air has to push on the bullet. Together, these two features (longer valve time and longer barrel) make it possible for 500 psi to do almost the same work as 2,000 in a modern slam-fire system with a shorter barrel.

The Bandit is supposed to be filled to 3,000 psi, but each rifle will exhibit slightly different performance characteristics. These characteristics can be discovered by shooting the rifle through a good chronograph. Experimenters can even remove the receiver's back cap and substitute a hammer spring of different length to change performance. Dennis made the spring a standard half-inch diameter, so you can easily buy bulk replacements at the hardware store and cut them to length.

Dennis now makes an external spring adjuster to allow owners to change power at will without disassembly. This device opens the way for much experimentation with an individual rifle.  The adjuster replaces the cap on the action tube by unthreading the cap on the gun and threading this one in.  No tools are needed to set the adjuster.  It has a knurled lock ring that acts as a jam nut that you can work with your fingers.  Currently not available.

Having said that, however, you should also know that these guns are not nearly as sensitive to small velocity variations as smallbores. Where 20 f.p.s. is the maximum velocity variation we often look for in a smallbore over the effective range of shots, with a big bore it is 100 - or even a bit more. Think about it - if your .177 group shifts by a half-inch at 40 yards, you really notice it; with a .50-caliber ball, you'll never see it.
I found that our test gun had four really good shots. I will describe how it shot in a moment, but first I want to tell you how I conducted the test.

The Bandit is a single-shot bolt-action breechloader with separate loading and cocking actions. You load by retracting the bolt. It stays wherever you put it because of the ball-bearing detent mentioned earlier.

A lead ball is loaded in the trough and pushed home with the bolt - a crisp, easy operation. Dennis has really calculated everything to make this a very slick-loading ball-shooter. The safety lug on the left of the bolt body provides some cramming action to firmly seat the lead ball in the rifling.

This test was done in 2003 and a .50 caliber was new to the market so projectiles were limited, but .495 round ball was still available.
Since that time bullet makers have made conical bullets for the .495 and other airguns have been made in .495, after this rifle had established the .495 bore size.

Dennis rifled his barrel very specifically to take a swaged .495 round lead ball. You can buy them at any good gun store that sells muzzleloading supplies, or they can be bought through the mail. You can cast your own balls, of course. The only thing you'll have to watch is the placement of the sprue when loading. Swaged balls are very uniform and have no sprue, so I recommend using them for best accuracy.

Now, this is an important point - DON'T USE THE BALLS SIZED .490! This is an alternative size for some .50-caliber muzzleloaders. They fit this rifle (very easily, in fact), but you won't get the gilt-edged accuracy of which the rifle is capable; nor will you get all the power and accuracy the rifle has to offer. I know, because I tried them.

When I went to the gun store to get ammunition, they were out of .495 balls. All they had were the .490 size Dennis told me NOT to use. But the next stop was the range, so what could I do?

I found that the smaller .490 balls shot okay, but nothing to get excited about. They produced 1.8-inch groups at 30 yards - good enough to blast a pop can, but not what Dennis had lead me to believe his gun could do. They ranged around 755 to 760 f.p.s. for the first shot on an 84-degree day. Since they weigh about 175 grains, that's about 223 ft.-lbs., which is nothing to sneeze at, but not up to spec for a Bandit.

My friend Earl McDonald and I shot most of these undersized balls at swingers 35 to 50 yards away. The rifle was capable of hitting a four-inch-square swinger about half the time at 50 yards when held offhand. That's pretty fair accuracy for stand-up shooting!

We had the swingers at 35 yards spinning wildly, barely missing a shot on the 3-1/2-inch paddle. The balls made some beautiful big lead splats when they dropped harmlessly to the ground near the base of the swingers.

Clearly, another test was required using the right ammunition. I was able to get to the range with what was needed a week later. The weather was a chilly 48 degrees, and both scuba tanks were operating at a 2,800 psi pressure level. There was no sun to warm them, so I had to use a manual air pump to complete each fill.


You don't need an expensive scope, a 2 1/2 x 32 or a 4 x 32 shotgun scope works very well.  The scope is already set for short range parallex and it can certainly take the recoil of an air rifle.  With the 2 1/2 power scope, you can shoot with both eyes open, using the scope as an optical sight.  I bought one of these scopes from a retailer for under $30.

The .495 Speer swaged balls worked like a charm! They loaded just as easily as the .490s, so the bolt leverage and rifling taper is obviously right.

Being a trifle larger, these balls weigh an average of 182-and-a-fraction grains. At 3,200 psi, the first shot moved out at 801 f.p.s., for a muzzle energy of 259.35 foot-pounds. Quackenbush rates his Bandit at 250 foot-pounds, but the truth is, with use, the gun loosens up and may well go just a bit faster than advertised. You can help this along with lubrication of the heavy hammer.

Also, owners will have to experiment with their individual rifle to learn the best maximum fill pressure. I have heard of shooters using a top pressure of 3,500 psi and getting even better results than mine, but you have to use a chronograph to determine this for sure. Remember, at some point more pressure will slow the gun rather than speed it up, so if you don't have a chrono, stick to 3,000 psi.

The REAL news with the .495 balls, however, is accuracy! Buckets of it, in fact. No sooner had we settled down to shoot than the first three balls went through the same hole at 30 yards. It was a hole so small a nickel covered it completely. Shot four didn't even disturb the paper as it passed through the group, so naturally shot five had to open it up to almost an inch! Until then, we were working on about 0.20 inches c-t-c.

The next group started out the same way, then another wide shot opened it as well. Fortunately, I happened to notice that the sandbags were creeping forward on the bench, and the wide shot was taken with the rifle resting on its reservoir. By pulling the bags back so they balanced the forearm about four inches from the end, the next ball went into the original ultra-tight group. After that discovery, everything was on autopilot.

As long as we kept the rifle rested with its forearm on the front sandbag about four inches from the end of the wood, the balls went to the same place every time. We filled the rifle after every second shot and then after every third shot, and the hits just kept on coming.

With a solid half-inch group under my belt and several others almost as good, it was time to move the target out to 40 yards. Even at that distance, there was no change in accuracy. The Bandit shot like a natural. Dennis has had reports of sub-one-inch groups at 30 yards from some of his customers, but we were able to achieve the same at 40 yards! And it wasn't hard to do. This utilitarian air rifle shoots as well as a fine Pennsylvania rifle when the right caliber balls are used.

No lubrication of ammunition is required. Neither is there any leading of the bore. The combination of relatively low velocity and pure lead balls make for a maintenance-free gun.

Because of the success of the Bandit and because Dennis also wants to try new things, he has experimented with other calibers in the rifle he calls the Bandit. Currently, he is making a .308 version that shoots conical lead bullets instead of balls. It develops over 200 foot-pounds with a 130-grain bullet. So, the mystique of a powerful air rifle is still present, but with conicals you get much greater range.

The Bandit is a fun airgun to own and shoot. It has enough power to do some serious hunting, yet it is uncomplicated enough for the first-time buyer to use, as long as he understands the general operational and safety issues of any gun. Off-the-shelf ammo means there's no problem feeding the gun - but remember to use only the .495-caliber ball. You have to have a means of refilling the reservoir with air, and we recommend using a scuba tank with this one.

Quackenbush Bandit
.50-caliber single-shot air rifle
Pro - Well-made and designed, extremely accurate, ammo available at gun stores, easy to load, easy to fill, has protective cap for the fill port, each rifle comes with a good pair of scope rings - a very affordable big bore air rifle with lots of potential for hunters and enthusiasts alike.
Con - Trigger has creep. Fill probe not a standard size, though one is provided with every rifle.
Cost - currently (2003) rifles are $580. Other versions with finer finish and wood grain available at higher cost.
Availability - Each rifle is handmade by Dennis Quackenbush. Call 417-993-5262, M-F, 9 AM-5 PM, Central.

1633.jpg (89961 bytes)
A real world comparison of the size of these airguns.  On the left is a Mauser rifle with a 24" barrel in .22/250 cal.  To its right,  is a 25" barrel  .50 Bandit.   I've included a yard stick to give perspective.  I dislike photos with no reference for perspective or such a tight crop that you don't see the whole item.


The standard rifle I make is right handed.  I can make left handed rifles (putting the machine cuts on left side or the right side is the same amount of work, so I don't charge extra for it) but you just need to tell me at the time of ordering so I can machine the parts for left hand.  It has a genuine left hand stock (a mirror image of the right hand stock).  See the Stocks page.

Currently made rifles have Weaver scope bases rather than the 3/8"
    dovetail.  Weaver bases are the type that are used on center fire
    rifles. weaver_base.jpg (149536 bytes)

click on picture to enlarge

Seeing the rings is to understand.  On the left is a 3/8 dovetail mounting ring and on the right is the scope ring for Weaver bases.
rings.jpg (53256 bytes)

There's been a change to the filler, now in use is a quick disconnect
    for filling.  There's a picture of it at the end of the owner's manual.
    Go to the home page, click on the Outlaw Manual and scroll down.



The original thought behind the use of the .50 cal. rifle was to be able to hunt on areas that would be too small for firearms use.  The use of a round ball was selected because it slows down quicker than a conical bullet and doesn't carry as far.  A fellow would be hunt medium size game and not have to worry that his shot would carry very far, as a firearm would.