1 - Part 3
We are looking at the .50-caliber Bandit air rifle made and sold by Dennis Quackenbush. In Part 1, we looked at the history of the rifle and its general design. In this part, we'll get it ready to shoot and also learn something about the big bores from history.
BIG BORES USE A LOT OF AIR
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. Price $50. plus shipping.
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.
GETTING READY TO SHOOT
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.
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?
In the next and final part, we will shoot the Bandit and wrap up this report.