PELLET GUNS ARE PEST ELIMINATORS

Written by: Der Luftmeister

Before ecologists taught us that every species of every type was needed, we regarded several species as downright pests. Among the species that seemed to be overly abundant and noxious were sparrows, starlings, pigeons, and rodents. In fact, there was a real need to reduce their numbers to keep their residues to a minimum around the barns and chicken houses. In those early days of airgun work, the selection of tools was nowhere near as broad as it is today. In fact, the pest hunter now has an almost limitless number of choices of rifles, sighting equipment, and ammunition. With spring coming on, perhaps you are realizing that you have a potential pest problem and you want to be prepared. It is with this in mind that we review some basic guidelines.

First, each situation is somewhat different when it comes to selecting an air rifle for use as a pest eliminator. There is a great difference in the tenacity to life exhibited by a mouse and a pigeon. The level of power required depends on the types of pests you need to eliminate. Second, different types of pests are generally encountered at different ranges. You may need to hit mice that are no more than one or two dozen feet away, but you may have to take a shot at a pigeon that is 40-50 yards away. There is a lot of latitude when it comes to using pellet guns on pests.

When selecting an airgun for eliminating pests, keep in mind that an airgun that is suitable for use on sparrows and mice at short ranges may not be suitable for use on pigeons at extended ranges. A 177 caliber air rifle that shoots at 500 ft/sec is suitable for the former but not for the latter. If your pest program reduction includes larger pests or even small pests at relatively long ranges, pick an air rifle of considerable power. Any of the 177 caliber rifles that shoot at 800-1000 ft/sec has sufficient power to dispatch small pests cleanly. Without going into a lot of theory, keep in mind that 20 and 22 caliber pellets weigh almost twice as much as some 177 versions, and they have a much larger cross sectional area. The result is that the larger calibers hit with much more clout and they are more effective on pests and game.

When planning your pest safari, keep in mind that the muzzle of your rifle is not placed against the animals. The target will be some distance from the muzzle, and the velocity of pellets falls off rapidly. If the muzzle velocity is 900 ft/sec, the remaining velocity at 40 yards will be much lower. Even if the kinetic energy at the muzzle is 12 foot pounds it may be only half that at a range of 40 yards. Select an airgun with sufficient power for the job intended.

Pests are not dispatched by pellets that are near misses. In fact, dispatching a pest cleanly requires the pellet to strike a lethal zone that is a very small target. Accuracy is absolutely necessary when shooting pests with an airgun. By all means select a few types of pellets and see how accurate they are in your rifle. Keep in mind that pointed and domed pellets generally hold their velocity better at longer ranges. If they are sufficiently accurate, select pellets that have a high ballistic coefficient when the range is likely to be long. Also, if the pest is one that requires little penetration, a hollow pointed pellet is a good choice. They generally expand well and deliver a heavy blow.

Although we will deal with scopes in more detail in a future blog, a scope is virtually a necessity when shooting small pests. Match the scope to the air rifle. If the type of pest shooting you plan to do calls for hitting small targets at rather long ranges, pick a scope that has sufficient magnification to give a good sight picture. If your pest rifle is a break action, make sure that the scope you choose is designed to handle the jerk that is produced when the piston comes to a stop and yanks the rifle forward.

You have selected a rifle, scope, and pellets so you are ready to go, right? Well, yes you are ready to go to practice. Practice shooting under conditions that simulate the type of field shooting you will do. It is one thing to sit at a bench and shoot groups and quite another to shoot the rifle from a standing position or from behind a tree. It is accuracy under field conditions that is the necessary ingredient when shooting pests

Spring is upon us and that means opportunities to eliminate pests. Get out the airgun, select some pellets and get ready to help restore ecological balance.

Stay pumped!

GASPING FOR BREATH

Written by: Der Luftmeister

My wife and I spend a considerable amount of time in areas at high elevation. During one summer a few years ago, we had some airguns along for recreation and testing. The battery included a couple of multi-pumps, a break action, and a rifle powered by carbon dioxide. Along the way, I added a fine Crosman 140 that had languished on the shelf of a pawn shop for over a year. In one shooting session, I set up the chronograph and started shooting across it with one of the multi-pump rifles. Knowing that particular rifle well, I was surprised to see that the velocity was considerably lower than it was the last time I tested it. While walking around the area, I became aware that I was breathing differently than back at home. That should have been no surprise at an altitude of 8,200 feet. Then it dawned on me that while I was having trouble getting enough air, so was the airgun!

At high altitude, the atmosphere is less dense so each breath brings in less air. In order to get enough oxygen, it is necessary to breathe more deeply and more often. When the airgun is pumped, each stroke brings in less air. The reason that the velocity is lower at high altitude is that the pumping is less efficient in the thinner atmosphere. I decided that this phenomenon needed to be explored in some detail. The airguns I had available were all rifles that I had tested extensively at home where the altitude is only about 800 feet.

Working at an altitude of 8,200 feet, I selected a dozen types of pellets and measured the velocity produced when the rifle was given ten pump strokes. What I found was that the average velocity at that altitude was 91% of what it was at 800 feet. With a second multi-pump of different caliber the results were almost exactly the same. Although I should have known better, I thought that a break action rifle might not be affected as much as the multi-pumps. What I found was that the break action gave a velocity at 8,200 feet that was just 87.4% of what it gave at 800 feet. The rifle tested is advertised to give 1,000 feet per second and low altitude it actually gives about 900 feet/second with pellets of normal weight. The effect of altitude at 8,200 feet reduces this value by approximately 100 feet/sec on the average. Keep in mind that a 10% reduction in velocity means almost a 20% loss in kinetic energy.

Having seen the loss in velocity at high altitude, it seemed that it might be useful to determine the effect at some intermediate altitude. Fortunately, one of the ranges we use during our travels is at an elevation of 5,500 feet so velocity testing was carried out there. The results were about as expected in some ways and surprising in others. With a dozen types of pellets, the multi-pump rifles gave average velocities that were about 94% of what they were at an elevation of 800 feet. The break action rifle gave almost exactly the same result.

Here we have something of a paradox. The break action rifle lost about the same percentage as the multi-pumps on going from 800 feet to 5,500 feet but lost about 4% more velocity on going from 800 feet to 8,200 feet than did the multi-pumps. Since the results are based on velocities with over a dozen types of pellets in each case, the effects seem to be real.

When the rifle powered by carbon dioxide was tested, it was found that the altitude produced no effect on velocity. That was expected because the pressure inside the gas cylinder is determined by the temperature but it is not affected by external atmospheric pressure. Your Tech Force 78 will give the same velocity regardless of the altitude as long as the temperature is the same. So will the precharged Tech Force TF50. Although I had no precharged pneumatic rifle for testing at that time, the altitude would have no effect on velocity. That is because the rifle is pumped to reach a specific pressure of compressed air inside the reservoir regardless of the outside pressure. What would be different is the number of pump strokes needed to reach that pressure!

There is another factor to consider. Keep in mind that at high altitude a multi-pump rifle can be given an extra stroke or two to compensate for the thin atmosphere. It is not possible to do this with a break action because cocking the rifle moves the piston into firing position. The amount of air that enters the compression chamber is fixed by the design of the rifle, and at high altitude that amount is smaller because the atmosphere is less dense.

The lower muzzle velocity and resulting lower kinetic energy have serious implications for the air gunner who heads to the mountains to hunt vermin. Depending on the type of airgun, it may be advisable to select a model with a little extra power. Although it is a topic for another time, the thinner air at high altitude retards the flight of the pellet less. This means that the velocity loss is not as rapid as it is at lower altitude. So, even though the muzzle velocity is lower, it is partially offset by the velocity being retained better. We will have more on this topic in a later blog.

Until next time, stay pumped.

TO BB OR NOT TO BB

Written by: Der Luftmeister

There is little doubt that most shooters, regardless of whether they shoot firearms or airguns, started with a BB gun. Mine was a Daisy No. 100 Model 38 single shot that was cocked by pulling the stock downward as in opening a double barreled shotgun. Dropping a single pellet down the muzzle was the only way to put the BB in place. If I recall correctly, that gun cost $1.75 at that time. In those days, there were two other BB guns were popular, the Daisy Red Ryder and the Model 25 pump.

Today, there are numerous BB guns available, but some of them are repeaters that can also be used as a single shot pellet rifle. These include models such as the Crosman 760, 66, and 2100 as well as the Daisy 880. Although these multi-pump models can be used with BBs, they have rifled barrels and shoot at high velocity when given several pumps. I have never favored shooting steel BBs through the rifled barrels. One old gun of this type that I examined had very pronounced grooves in the rifling where a constant diet of steel ammunition had scraped away the metal. When I refer to a BB gun, it is the smooth bore type that comes to mind.

Three of the fine BB guns available from Compasseco are the Winchester 1894, the Red Ryder, and the Grizzly Model 840. It is the last of these that will be featured in this essay. My association with the 840 goes back several years to when I picked up a like new specimen in a pawn shop for $8. I was not really concerned much with this type of gun at the time, but thought that it would fill a gap in my modest collection of airguns. I set the gun aside without much thought, but eventually decided to work with it.

For shooting down the hallway, I usually set up a brown paper bag that has folded newspapers toward the back and a few crumpled up papers in front. For a BB gun that is all you need. I taped a target to the bag and started shooting. Wow! At 25 feet, my first three shots gave a very small cluster. None of my other strictly BB guns shot like that.

The Daisy 840 loads at the receiver rather than in a steel shroud around the barrel. That means that the barrel is a full 19 inches in length rather than the short tube used in guns like the Red Ryder. Being loaded by means of a bolt action, the breech is open when the bolt is pulled back. The shooter has a choice of pushing the bolt forward to load a BB from the 350 shot reservoir or placing a single pellet in the open breech. Cocking the 840 requires the pump handle which doubles as the forearm to be pulled down and pushed back in place. Only one pump stroke can be used so the power level is similar to that of other BB guns that have a cocking lever.

The 840 Grizzly is a handsome rifle that resembles a pump rimfire. It has a raised ridge on the receiver that has grooves which can accommodate clamp on mounts for a scope or red dot sight. The open sights are better than on most BB guns, and the rear sight is adjustable for elevation. The safety on this slick BB gun is located in the trigger guard.

Just for fun, I set up the chronograph to see what velocity the 840 gave. My first few shots were so uniform that I decided to send 20 BBs across the chronograph. The result was astounding. The average velocity was 304 ft/sec with a standard deviation of only 3.2 ft/sec! The velocity is right in line with most single cocking BB guns, but the velocity uniformity is excellent. When I switched to Daisy Max Speed pellets the average velocity was 278 ft/sec with a standard deviation of 3 ft/sec. The velocity with pellets is lower because a pellet weighs about three grains more than a BB.

I got some small groups shooting with open sights, but wanted to see what the 840 was capable of so I mounted a 2-7X AO airgun scope on it. With Daisy Max Speed pellets what I got at a distance of 25 feet were five 5-shot groups that averaged 0.56 inch. I later got almost the same results when using Gamo Match pellets. Although the accuracy was not as good as with pellets, BBs grouped quite well.

Now you may think that this would not be possible from a smoother bore. Remember that pellets have most of the weight in the head and the thin, hollow skirt acts like the webbing on a shuttlecock used in badminton. The pellet flies straight on regardless of whether it is spinning or not.

Most shooters of BB guns are content to hit pop cans, but the Daisy 840 is capable of much better accuracy than that. In my opinion, a better starter BB gun does not exist. If you have a youngster who wants to enjoy air gunning with you, check out the 840. It does not require a lot of pumping and it will shoot the same .177 pellets as the Tech Force BS4 or TF79 that Dad shoots.

PELLET DIMENSIONS

Written by: Der Luftmeister

Some time ago, I conducted some accuracy tests with a Daisy 22X multi-pump rifle. That model is a 22 caliber wood and metal rifle of modest power that has a well shaped stock and forearm. I had mounted a 3-12X AO airgun scope and was getting groups that averaged around 0.23 inch at 10 yards. In fact, I was well pleased with this performance. Then, without warning, the groups started measuring about three times this size. What had happened? I had changed to a different type of pellet.

The pellets that gave the small groups were the inexpensive pointed Daisy Max Speed. The bad groups were obtained with Crosman Premier, wadcutter, and pointed styles. Being curious, I continued to shoot and even tried several other types of pellets. Some grouped like the Daisy variety, some grouped poorly like the Crosman types, and some were in between. What did these observations mean?

Not all pellets are created equal. They differ in weight and point design as any air gunner knows. If you are familiar with the history of Crosman airguns, you probably know that several classic models are repeaters. The outstanding Crosman 600 pistol and Model 400 rifle come to mind although there are others. These models utilize an inline magazine to hold pellets. The pellets are pushed forward by a spring-loaded plunger so that each pellet is held with the nose pressed against the skirt of the pellet in front. If pellets having rounded or pointed noses are loaded in the magazine of these guns they do not feed properly. Moreover, if the skirts are made very thin and soft (as some are), there is a good chance that the pellets may be deformed enough to prevent proper feeding. Consequently, Crosman pellets have traditionally been produced with skirts that have thicker walls than most others.

It has also been my observation that Crosman pellets seem to be constructed of a harder alloy than are most others. Certainly they are made with shallow cavities and very sturdy nose sections. The result is that they give excellent penetration with minimal deformation.

While searching for some way to rationalize the accuracy results that I had obtained, it eventually dawned on me to take a look at pellet measurements. What I found was that in 22 caliber, the Crosman pellets have an average head diameter of 0.216 inch while the skirt averages about 0.222 inch in diameter. On the other hand, the Daisy Max Speed has an average head diameter of 0.215 inch, but the skirt averages around 0.226 inch. It is reasonable to assume (whether rightly or wrongly) that the diameter of the Crosman pellets might be kept on the small side so they would feed reliably through magazine rifles and pistols and enter the chamber easily.

Well, at this point I knew that the larger Daisy pellet shot well while the smaller Crosman pellets did not, at least in this particular rifle. What about other pellets? Having measured a great many types, it was easy to select some others of similar dimensions. Gamo pellets are virtually identical in dimensions to the Daisy variety so I tried Gamo Master Points in the rifle. Sure enough, the group size was almost the same as when the Daisy pellets were fired, and the groups averaged 0.24 inch. Groups with the Meisterkugeln, which has a skirt diameter of 0.225 inch, gave an average size of 0.28 inch.

The tests described were carried out in a cursory fashion, and I need to do a lot more work to make sure that the effects seen are reproducible. However, it is well known that airguns are finicky about the type of projectile used. I am not ready to say definitively that the skirt diameter is the critical factor, but for what ever reason, my Daisy 22X has definite preferences. Among rimfire shooters, it is well known that chamber dimensions vary considerably between rifles, and that is one of the reasons why specific types of ammunition shoot better in certain rifles. Perhaps the skirt diameter is a measurement that is critical to accuracy in certain air rifles.

Airgun shooting is primarily about accuracy. When dispatching pests, I normally like to use specific types of pellets because of their performance. However, even in that case I reach a compromise between pellet design and accuracy. If you do not hit the target, penetration or expansion makes little difference. If your airgun is not shooting quite up to par, it may be time to try some different pellets, especially ones with different dimensions. Serious air gunners know this of course, and they select ammunition carefully.

Until next time, stay pumped.