How to mount a scope: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4

This report covers:

  • More scope stuff
  • Swap the rings
  • Spiraling pellets
  • What to do about spiraling pellets
  • Misaligned scope
  • How to correct the misaligned scope
  • Setting up a rifle
  • BB did NOT say all bundled scopes are bad!
  • Scope stiction
  • Sighting-in for one distance
  • Summary

More scope stuff

While we are finished with mounting a scope, there is more to tell. A lot of it does come to the forefront when you mount a scope, so it is germane to this discussion. We have touched on some of it before, but today I hope to tell you how to deal with it.

Swap the rings

This is a trick that can help resolve many of the problems we will see today. It’s also one of the big reasons that I prefer 2-piece rings to 1-piece. Someone asked last time what can be done when the scope’s axis is out of alignment with the barrel. Well, that is often the case. The way you find it out is — after you sight the rifle in you try to shoot at different distances and discover that your pellet is off to one side or the other. What can be done? read more


How to mount a scope: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • The olden days
  • What needs to be done
  • Eliminate cant
  • The tale
  • More information
  • The scope must be angled down
  • Adjusting the scope too far right is also bad
  • Not experts
  • Position the eyepiece
  • Adjustable scope mounts
  • Is it enough?
  • Points to remember
  • Summary

The olden days

When I started shooting in the 1950s, scopes were not that common, especially on airguns. I was as intrigued by them as anyone, believing that they increased the accuracy of whatever they were mounted on. 

Well, they don’t. What they do is make it easier to shoot accurately with a given airgun or firearm. But they can only do it if they are mounted on the gun correctly and then sighted in properly. This series is dedicated to addressing all that is inherent in both mounting a scope correctly and then sighting it in properly.

What needs to be done

To properly mount a scope there are several things to consider. Here is a list. read more


John Wayne Lil’ Duke BB gun with scope: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Lil Duke and scope
John Wayne Lil’ Duke BB gun with scope.

Part 1
Part 2
Part 3

This report covers:

  • The scope base
  • Mount the scope
  • The test
  • Sight in
  • Air Venturi Steel BBs
  • Hornady Black Diamond BBs|
  • Avanti Match Grade Precision Ground Shot
  • Smart Shot
  • Old Dust Devils
  • Dust Devil Mark 2
  • Discussion
  • Oh, fudge!
  • Summary

Today I mounted the scope on the Lil’ Duke BB gun and tested the gun for accuracy a second time. This was an interesting test! Read all of it before you form any lasting impressions, because there is a surprise coming at the end.

The scope base

The scope base comes in the box with the Lil’ Duke. It’s in a plastic bag and the instructions how to attach it to the BB gun are in the owner’s manual. I have used BB-gun scope bases like this before so the the job went quick.

The base itself is plastic and attaches to the gun with a screw in the back and by fitting the front end under the rear sight. The screw comes out from the top of the pistol grip. Remove it, attach the mount and screw it back into the hole. It has machine threads and I could never get it tight with the mount installed. read more


Can a fixed-barrel airgun have barrel droop?

by B.B. Pelletier

This report is in response to a comment Pyramyd Air got from a customer who doubts that fixed-barrel airguns can ever droop. His position is that they can only have droop if the barrel is heated in some way (as on a firearm that fires very fast) or if the gun is assembled in a shoddy fashion.

He said he believed barrel droop is only commonly found on breakbarrel airguns, which is why he said he would never own one. He thought that droop was mostly caused by the metallurgy of the barrel.

Today, I’d like to address the subject of barrel droop in detail. It can be caused by many things, but poor metallurgy isn’t one of them. Barrels do not bend from cocking, despite what some people may think. It is true that a barrel can be bent by human force, but the force required to do so is much greater than the heaviest cocking effort on the most powerful magnum airgun. So, poor metallurgy is not a contributor to barrel droop.

What is barrel droop?
I will explain what barrel droop is in detail later in this report. For now, I’ll just say that barrel droop is a condition in which an air rifle shoots so low that the scope cannot be adjusted to hit the target.

You must understand that most scopes cannot be adjusted all the way to their highest elevation settings and still operate correctly. This will differ from scope to scope, but generally most scopes do not work well when adjusted above three-fourths of their maximum elevation. It’s imperative that they get on target before reaching that height, and a drooping barrel can prevent that.

History
Throughout the first five decades of spring-piston air rifles, no one ever heard of barrel droop. It was a non-issue. That was because nobody bothered scoping their air rifles.

The sights on most breakbarrel guns are attached to the barrel, both at the front and rear, so they’re in line with the bore — as long as the bore is drilled straight through the barrel, which it seldom is. The amount of misalignment is usually measured in the thousandths of an inch — an amount the sights can easily account for.


With both the front and rear sight attached to the barrel, there’s less chance for misalignment.

In the 1960s, retailers began attaching scopes to airguns to sell more of them. Firearms had been using scopes for some time, and the general belief among shooters was that scopes extracted the maximum accuracy from any gun.

But scopes had a problem, as well. They were attached to the spring tube of the gun, which isn’t integral with the barrel on a breakbarrel airgun. For the first time, the alignment of the spring tube and barrel came into question.

It soon became known that most breakbarrel guns have a barrel that slants downward from the axis of the spring tube. In the 1960s and ’70s, breakbarrels were hand-selected for scope use when they exhibited less slant than other guns of the same model. You can read about this selection program in both the Air Rifle Headquarters and Beeman catalogs of the period.

What those catalogs didn’t address was the fact that fixed-barrel airguns can and do sometimes have the same barrel slanting problems. They didn’t address it because, at the time, scoping airguns was brand new and not that much was known about it. The people scoping the guns often installed simple fixes, such as shimming the rear ring, and didn’t even think about why they were doing it.

Why the barrel droops
The comment that prompted this blog went on to say that barrel droop was caused by poor metallurgy. Evidently, the writer thought that “droop” referred to a barrel that was curved (or bent) downward — which is not the case. The term “droop” doesn’t refer to a barrel that is somehow curved. It means a barrel that points in a direction away from the sight line, so the axis of the bore and the sight line are diverging. To correct for this droop, the scope has to be repositioned to align with the axis of the bore.

We all understand that a pellet starts falling the moment it leaves the muzzle. The farther from the muzzle it goes, the faster it falls; so the line of flight is actually an arc, rather than a straight line. To align the sight line of the scope with the axis of the bore, we have to align the scope to look downward through the line of flight. To be effective — that is to get any distance over which the pellet is on target — the sight line is made to pass through the arc of the pellet twice — once when the pellet is close to the gun and again when it’s farther away.


The scope is angled down through the pellet’s trajectory. This illustration is greatly enhanced for clarity. This alignment is done the same for firearms and airguns, alike.

But the question is, “Why does the barrel point downward?” With a breakbarrel, it’s usually because of how the breech locks up at a slight angle that causes the downward slant. Some guns, most notably target breakbarrels, overcome this with barrel locks that cam the breech tightly against the spring tube in a straight line. Most guns rely on the spring-loaded detent to both align and hold the barrel during firing. If there’s a weakness, it’s at this point. When a breakbarrel with an unlocked breech fires, the barrel tends to flex in the direction the barrel is hinged. If the barrel broke upward to cock, the problem would be reversed and we would have a barrel “climb” problem.


A breech lock like the one on this HW 55 ensures that the barrel always aligns with the sights — provided the rifle is designed that way.

Do you now understand that the barrels are perfectly straight, and it’s just the angle of the bore’s axis relative to the line of sight that creates the drooping problem? Good, because that’ll make the following easier to understand.

What about underlevers and sidelevers with fixed barrels?
How can a fixed-barrel rifle have droop? Easy — the barrel isn’t attached to the gun with the bore parallel to the line of sight. Presto! Automatic sighting problem. Or the scope base that’s attached to the spring tube may not be aligned with the axis of the bore. Or the bore may be drilled off-center; and although the outside of the barrel is parallel to the sight line, the bore’s axis isn’t. Any of these three things can happen.

Bore not drilled straight
This is very common. It’s extremely difficult to drill a deep (long) hole straight through a steel bar. The drill bit can wander off-axis as it bites its way through the steel, or it can be off-axis all the way through the bore if it isn’t correctly set into the holding fixture before the drilling begins. I’ve had barrels with bores as much as a quarter-inch off-axis with the outside. Granted that’s extreme and uncommon, but it demonstrates the possibility.

The only way a barrel-maker can ensure concentricity of the bore to the outside of the barrel is to machine the outside of the barrel after the gun is rifled.

Barrel isn’t aligned with the spring tube read more


Air Arms TX200 Mk III air rifle: Part 3

by B.B. Pelletier

Part 1
Part 2


Air Arms TX200 Mark III air rifle is impressive in its optional walnut stock.

Today, we begin our look at the accuracy of the legendary TX200 Mark III. Since the rifle has no sights, I mounted a Hawke 4.5-14×42 Sidewinder Tactical scope in two-piece UTG Accushot 30mm medium rings. These rings are tall for a medium-height ring, but the TX200 cheekpiece is so high that many higher rings will be just right and fit the shooter perfectly. I know they come very close to a perfect fit for me, and the 42mm objective bell still clears the spring tube by a lot.

I’m showing a photo of the rifle with the scope mounted because you’ll see that the end of the scope hangs over the back of the loading port. In a TX200, that isn’t a problem unless you have summer sausages for fingers, because the loading port is very large — but on other underlevers and some sidelevers it may be. The Hawke is not a long scope, so this clearance is something a new TX owner needs to consider.


The Hawke scope hangs over the loading port just a little, but was not in the way during loading. See how much clearance the 42mm objective tube has above the spring tube?

What pellets to shoot?
This question is the one every shooter asks whenever they get a new gun — air or firearm. I have a lot of history with this rifle, but in the time since I last shot it many good pellets have come to the forefront. The JSB Exact RS is just one example. I know that Crosman Premier 7.9-grain domed pellets are averaging 958 f.p.s. in my rifle, and that means the lighter 7.3-grain JSB Exact RS will probably top 1,000 f.p.s. Six months ago, that might have turned me off; but after the exciting 11-part “Pellet velocity versus accuracy test” proved that harmonics and not velocity is what causes inaccuracy, I see no reason not to try a faster pellet.

I sighted in with Beeman Kodiaks, just because I used to shoot them in my other TX for field target, and they always worked well. But in reviewing my past reports, I see that this will be the first time I’ve shot 10-shot groups for a report. What a difference that makes!

Naturally, group one was with the Kodiaks. I had hoped to shoot around my aim point, but as you’ll see, that didn’t happen. The group may be a trifle larger than it should be, because for the last four shots I was guessing where to put the crosshairs.


Ten Beeman Kodiaks went into this group that measures 0.584 inches between centers at 25 yards.

Notice how round the group is? Actually only the first shot went low and right — the rest made that small hole you see. And that was exactly where the aim point was, so after six pellets there was nothing to guide on. Nine of the ten pellets went into a group measuring 0.302 inches!

Next, I tried 10.34-grain JSB Exact Heavies. Often, I get the best results with this pellet in an accurate .177 rifle. Ten shots in the TX made a group that measures 0.523 inches. Let’s see what that looks like.


Ten JSB Exact Heavies made this group that measures 0.523 inches between centers at 25 yards. It looks more open than the Kodiak group, but it doesn’t have the one straggler the Kodiak group does.

Next, I tried the light JSB Exact RS pellet. The point of impact shifted up about an inch, and the group opened to 0.687 inches. It’s still fairly round, but more open than the first two by a lot. The RS probably isn’t the pellet for this TX. read more


Learning to shoot with open sights: Part 5

by B.B. Pelletier

Announcement: William Davis is this week’s winner of Pyramyd Air’s Big Shot of the Week on their facebook page. He’ll receive a $50 Pyramyd Air gift card! Congratulations!

Willliam Davis is this week’s Big Shot of the Week. Here he’s showing off his Crosman pistol with shoulder stock. He says he gets one-hole groups with it.

Part 1
Part 2
Part 3
Part 4

It’s time to advance through the 20th century and look at open sights as they evolved. We now know that by the beginning of the 20th century almost everything that could be done to increase accuracy with open sights had already been done. There were a few nice touches that were added, but most of the hard work had already been done. But that didn’t mean the gun makers were finished. There were always new embellishments that could be added. Yet, some of the sights that were most popular in the 20th century actually got their start in the 19th century.

Buckhorn rear sights
Buckhorn rear sights were actually popularized in the American West in the second half of the 19th century. But they became very trendy around the 1920s, and the trend lasted well into the late 1950s — past the time when they made any real difference to shooting and were more of an adornment that some shooters expected to see. Though they were originally mounted on single-shot muzzleloading rifles, they are perhaps best-known as the sights for Western-style lever guns.

A buckhorn sight is very distinctive.

When you see a full buckhorn rear sight, you instinctively know it was created for some specific purpose, though there’s very little literature that actually explains it. I’ll now go out on a limb and explain the sight as I understand it.

A buckhorn rear sight is a ranging sight. What that means is that it’s a sight that can quickly be “adjusted” to shoot at different ranges without touching the sight. All you do to change the distance is change the sight picture. There are three clear sighting options when you sight through a buckhorn. The sight is nearly always associated with a post-and-bead front sight; and when it isn’t, I suspect someone has changed one of the two sights — either front or rear.

The bead can be held in the small notch at the bottom of the buckhorn for close shots. I would tell you that this is the 50-yard sight picture, but that would be misleading. On some guns, it might be exactly that, while on others the distance will be different. Suffice it to say this is the closest range at which the sight can be used without any adjustment.

When the muzzle is elevated until the front bead appears in the center of the hole described by the arms of the buckhorn (sort of like using a large peep sight), you have the middle range. Again, I can’t tie this to a specific distance without referring to a specific gun. And when the muzzle is elevated so the bead is between the points of the horns at the top, you have the longest range at which the sight can be used without adjustment.

All three ranges are achieved without moving the rear sight — by simply elevating the front post in relation to the buckhorn. That’s the purpose of the buckhorn sight as I understand it. If you have one on a 44/40, the three distances will be different than if you have one on a .22 rimfire. You should bear in mind that when the buckhorn was invented, men typically had just one rifle and they learned it well. It wouldn’t take long to become accustomed to the ranges for which their own rifle was sighted.

Now for the bad news. Most riflemen dislike the buckhorn, finding it crude, obstructive and generally not useful. Townsend Whelen was very outspoken against it. And most shooters who own one simply use the lowest notch for sighting, so the extra capability goes to waste. But it looks very Western, hence my remark about it passing into the realm of a fad.

Semi-buckhorn
Worse than the buckhorn is the semi-buckhorn, which is neither fish nor fowl. It was even more common than the buckhornand appeared on most rimfire rifles of the 1940s and ’50s because of its supposed popularity. It’s not a ranging sight like the buckhorn — just a stylistic form that’s supposed to look cool. It was popular at the same time the semi-beavertail forearm was considered necessary. Nobody asked shooters what they preferred. Companies just attached these sights to their guns and that was what you got– not unlike the fiberoptics of today.


The semi-buckhorn rear sight is just a stylized rear notch with two long arms that add nothing to the functionality.

Fiberoptics
Fiberoptic sights have synthetic or glass tubes that collect light and transmit it to a point at the end of the tubes. The point is oriented toward the shooter’s eye so the fiberoptic tube looks like a bright pinpoint of light. The object is to align the two rear sight dots with the front sight dot so the three appear to be in line. The front dot is usually red or orange and the rear dots are usually green.

It all sounds fine but for one thing. Red is the single color that’s hardest to see for colorblind people, and approximately 14 percent of all men are colorblind in some way and to some degree. Red-green is the most common type of colorblindness. That doesn’t mean these people can’t see the colors red and green, but they have problems seeing all shades of those colors, as well as other colors that are similar. Traffic signals compensate for this by putting yellow into the red and blue into the green, but I’ve seen some fiberoptic tubes that were so dark that I couldn’t tell what color they were. They are always red when that happens, by the way.


The typical fiberoptic front sight is a single red tube like this one from TruGlo. read more


Learning to shoot with open sights: Part 4

by B.B. Pelletier

Part 1
Part 2
Part 3

This series began with the earliest sights that were both primitive and simplistic. Then, we looked at the evolution of peep sights, starting back before 1840 and progressing to around 1903.

There’s a lot more to be said about both open and peep sights. It was at this point in time that they each began to develop along separate lines. I think I need to concentrate on one type of sight per report to keep things straight. In today’s report, I’ll look at open sights from around the middle of the 19th century until today.

Open sights evolved rapidly after the American Civil War, which ended in 1865. Not that all the innovation was done in the U.S., mind you, but that was a time when the world of firearms was advancing though technological stages, and the sights kept pace with everything. Other wars around the world at the same time drove the armies of many nations to push the limits of firearms; and we got smokeless gunpowder, fixed cartridges, breechloading arms and eventually repeating firearms from this era.

In 1850, a military firearm was loaded at the muzzle and carried but one shot. Repeaters at this time were novelties and even dangerous experiments because of the volatility of black powder. These single-shot martial arms were accurate to about 400 yards on man-sized targets.

In 1900, there were repeating firearms holding 10 self-contained cartridges filled with smokeless powder and spitzer (pointed) bullets that could shoot accurately to more than one mile distance. Most of the primary designs we use today had been invented.

I stopped discussing open sights when I started my look at peep sights; but even though the advances in open sights were not as great in terms of the improvements they contributed to accuracy, open sights did advance in parallel with peep sights.

Range-driven improvements
The old black powder arms were accurate; but because they shot their bullets so slowly, the trajectories were huge. Bullets dropped by many feet on their way to the target. We all like watching Matthew Quigley shoot his big Sharps rifle at distant targets, but how many people appreciate that his bullets are dropping by 60-80 FEET before they impact the target?

Enough fantasy. Let’s get real for a moment. In 1874, the U.S. and Irish rifle teams shot a match at the Creedmoor range on Long Island to decide which nation had the world champion marksmen. They shot at targets at 800, 900 and 1,000 yards. At 1,000 yards, the bullets from the Americans’ .45-caliber rifles dropped more than 100 feet. So, they had to set their sights to compensate for this tremendous drop. A 550-grain .45-caliber lead bullet starting out at 1,400 f.p.s. will drop 114.69 feet when it gets to 1,000 yards.


This model 1873 Springfield Trapdoor carbine rear sight (from 1878) is graduated to 500 yards on the ramp and to 1,100 yards on the upright standard. There’s another sight at the top of the standard that’s sighted even farther — perhaps 1,300 yards. Image copied from Trapdoor Springfield by M.D. (Bud) White and B.D. Ernst, copyright 1980, Beinfeld Publishing, Inc.


This 1879 Remington rolling block rear sight on an Argentine military rifle chambered for .43 Spanish (11.15 x 58R) is elevated to shoot 400 yards. By flipping the standard straight up, the rifle can shoot out to 900 yards accurately.

I mention this because airgunners everywhere are so willing to condemn the .22-caliber pellet for having a “rainbow trajectory.” Folks, they don’t know the meaning of that term! And this is the reason that I refuse to give up my fascination for firearms — because I often find remarkable parallels between them and airguns. But some shooters will watch Quigley and then opt for the fastest .177 they can buy, so their pellets don’t drop too much at long range! To heck with that! Instead, take the time to learn where the pellets will drop and shoot the more accurate, heavier pellets. That’s what Quigley did.

So, the military rear sights of the 1870s were long affairs that had inclined ramps to raise them up for long-range shots. By 1900, this had been taken to the absurd limits of 2,000-yards. Nobody could see that far on the battlefield to shoot accurately; but by this time, military leaders were espousing area fire and talked about “beaten zones” and “cones of fire.” They were thinking of rifle bullets in a way similar to artillery shells, except they didn’t explode, of course.


By the turn of the 20th century, military leaders were thinking in terms of 2,000 yards and indirect plunging fire, as this 1896 Mauser rear sight shows. Image copied from Mauser Bolt Rifle, Third Edition by Ludwig Olson, copyright 1976, E. Brownell & Son. read more