Posts Tagged ‘Optics’

TX200 Mark III: Part 6

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5

Air Arms TX200 MkIII air rifleBB’s TX200 Mark III.

This is my second trip to the rifle range to shoot the TX200 Mark III at 50 yards. Last time, I shot only heavy pellets; today, I’ll shoot the hopefully more-accurate lightweight pellets, plus one JSB medium-weight pellet that several blog readers have had success with.

I also shot the rifle laying across the sandbag, instead of in the long groove down the center. Several readers said that was the best way to rest the rifle directly on the bag.

TX 200 Mark III rested lengthways
When I tested the rifle last time with heavy pellets, this is how it laid on the sandbag.

TX 200 Mark III rested sideways
For most of today’s test, the rifle laid sideways on the bag.

The day was perfect for shooting pellet guns at long range. There wasn’t a breath of air during the entire session.

Crosman Premiers
The first pellet I tested was the Crosman Premier lite — a 7.9-grain dome that some say is the most accurate pellet of all in the TX200. The group landed about 2-1/2 inches above the aim point because the rifle was still sighted for heavy pellets. But it was centered perfectly, and 10 pellets made a group measuring 1.077 inches between centers. That’s not a bad group, but I’ve seen TX200s do better at 50 yards.

TX 200 Mark III Premier lite sideways group
The first group was 10 Crosman Premier lites. It measures 1.077 inches between centers.

That was a good start. The group was only slightly larger than the smallest group fired in the session before, which was 1.042 inches.

Following the first group, I adjusted the scope down several clicks. I wanted to keep the shots on or near the bull at which I was aiming.

JSB Exact 8.4-grain dome
Next up was the JSB Exact 8.4-grain dome, a pellet that several readers said was the most accurate one in their TX200s. Alas, that wasn’t the case in my rifle. When the first 5 pellets landed in a very vertical 2.40 inches, I stopped shooting. There’s no way the last 5 shots can improve things. Clearly, this isn’t the pellet for my rifle!

TX 200 Mark III JSB Exact group
Five JSB Exact 8.4-grain domes landed in 2.4-inches between centers. This is not the pellet for this rifle.

JSB Exact RS
The next pellet I tried was one I had high hopes for — the 7.3-grain JSB Exact RS dome. It does so well in so many spring rifles; but, once again, the TX200 Mark III is not one of them. Ten pellets made a group that measured 1.957 inches. It’s a vertical group, as well.

TX 200 Mark III JSB Exact RS group
Ten JSB Exact RS domes made this 1.957-inch group. Another non-starter for my TX200.

Air Arms Falcon
About this time I was suspecting that the rifle does not like lightweight JSB domes. The next pellet up was the Air Arms Falcon, another lightweight domed pellet that’s also made by JSB. While Falcons are great in many air rifles, the first 5 landed in an open group measuring 1.658 inches, and I stopped right there. It looked like this pellet wasn’t for my TX, either.

TX 200 Mark III Falcon group
Five Air Arms Falcons spread out to 1.658 inches, so I stopped. No sense finishing the group.

What was happening?
Three out of 4 pellets I brought to the test were not good. Had I made a mistake with the Premier lites, as well? Was that good first group just a random event? I decided to shoot another one to see. This time, though, I laid the rifle the long way in the bag to see if there was any discernible difference.

Ten pellets went into a group measuring 1.241 inches this time. That is much closer to the first group than any of the other 3 pellets tried on this day, though it’s still larger. Maybe, laying the rifle lengthways made the difference? I don’t think so.

TX 200 Mark III Premier lite lengthways group1
Ten Premier lites went into 1.241 inches when the rifle was laid lengthways on the bag.

I decided to shoot another group with the rifle laid lengthways, again, just for comparison. This time I hit the jackpot and all 10 pellets went into 0.658-inches.

TX 200 Mark III Premier lite lengthways group2
Now, that’s a group! Ten Premier lites in 0.658 inches. The rifle was laid lengthways, once again. This is what I was expecting to see from my TX.

Lessons learned
The TX 200 Mark III is capable of phenomenal accuracy at 50 yards, even when rested on a sandbag. From the limited testing I did I can’t say laying it crossways or lengthways is better. It works well both ways.

My rifle seems to shoot best with 7.9-grain Crosman Premier lite pellets. It does not seem to like any light pellets made by JSB.

This is not the end of our testing. Pyramyd Air has sent me a new TX200 Mark III that I promised you I would test right out of the box. Some of you have been concerned that my rifle is too well broken-in, and you think it may not reflect what you will get if you buy one. So, we shall see!

As a final note, I’d like to point out that I got several groups that were okay with the Premier lites and one group that’s exceptional. That’s the way it goes with any airgun — I don’t care which one you’re talking about. All the talk about half-inch groups at 50 yards has to be taken with this firmly in mind. You’re going to shoot larger groups most of the time.

That being said, Premier lites seem to be the most accurate and also the most forgiving pellet we’ve tested in my TX200. They may not always shoot into a super-tight group, but they’ll always shoot where you want them to. That’s what’s important.

TX200 Mark III: Part 5

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3
Part 4

TX 200 Mark III
BB’s TX200 Mark III.

Yesterday, I shot the TX200 Mark III at 25 yards and discovered that it can shoot accurately when rested directly on a sandbag. Today, I’ll take the rifle to the range and shoot it again at 50 yards.

I decided to continue shooting with the rifle rested directly on the bag because it seems to work well, and also because I haven’t settled down yet. The bag-rested results should be a fair representation of what the rifle can do.

The day was dead calm throughout the test. Conditions were perfect for the rifle to do its best. But the results were most interesting and not what I expected.

H&N Baracuda Match
You will recall that, yesterday, I got the rifle sighted-in with the point of impact hitting about quarter-inch high and a half-inch to the left of the aim point. I left the scope setting where it was, so you could see what happened out at 50 yards. I’m shooting with the same H&N Baracuda Match pellets that were used yesterday.

TX 200 Mark III H&N Baracuda Match group 50 yards

Ten H&N Baracuda Match pellets didn’t do very well at 50 yards. Yes, there’s the one pellet off to the left, but there are 3 more to the right of the main group. Group measures 2.2 inches between centers, with 9 pellets going into 1.199 inches.

The new point of impact (center of the group) is about 2-1/2 inches low and 1 inch to the left. This pellet dropped 2-3/4 inches, going from 25 yards out to 50 yards. The group is pretty large, measuring 2.2 inches between centers. It was shot 2 that strayed over to the left. The other 9 pellets are in 1.199 inches, or about one inch less. That’s still on the large side.

JSB Exact Heavy
Next up were JSB Exact Heavy pellets. They weigh 10.3 grains and are often the most accurate pellets in premium airguns. They certainly were this day, as the first 10 turned in a group measuring 1.042 inches. It was the best group of the day.

TX 200 Mark III JSB Exact Heavy group 1 50 yards
Ten JSB Exact Heavys made this 1.042-inch group.

The other 2 groups I shot with the JSB Exact Heavy pellets were larger. One measured 1.289 inches, and the other measured 1.66 inches. I did adjust the scope between groups, but I was careful never to hit the aim point of the target bull.

TX 200 Mark III JSB Exact Heavy group 2 50 yards

 The second group of JSB Exacts measures 1.289 inches between centers.

 

TX 200 Mark III JSB Exact Heavy group 3 50 yards

The third group of JSB Exacts measures 1.66 inches between centers.

Crosman Premier Heavy
Seeing that I’d given the JSB Heavys a fair chance, I then shot a group of 10.5-grain Crosman Premier Heavys. They made a 10-shot group measuring 1.365 inches between centers. Since its size is about in the middle of the 3 JSB groups, I think it’s safe to say this pellet is about as accurate as the JSB Exact Heavy. I’m not making any claims, though, because I don’t think I’ve done the TX200 Mark III justice in this test.

TX 200 Mark III Premier Heavy group 50 yards
Ten Crosman Premier Heavys made this 1.365-inch group at 50 yards. That puts them on par with the JSBs.

The bottom line is that I’m not satisfied with these test results. I’ve seen this rifle do better, and I believe it still can — I just need to change something. I’ve never before shot a spring rifle directly off a sandbag at 50 yards, but I don’t think that’s the problem. I think I was using the wrong pellets.

Some observations
Remember at the beginning that I told you how far the group dropped when I went out to 50 yards with the 25-yard zero? I also shot the TX200 at 100 yards on this day. I didn’t shoot an entire group, just 3 JSB Exact Heavy pellets. I used the 50-yard zero after adjusting the scope at the range. The 3 pellets went into about 6 inches, but what’s really interesting is the fact that they struck the target more than 2 FEET below the aim point. Don’t let anyone kid you that shooting at 100 yards is simply double shooting at 50 yards. The transition out to 100 yards is very dramatic! I did this just as an aside to see what would happen. Well, I saw all right!

I also think by shooting only heavy pellets on this day that I hindered the TX200′s chances to shine. I want to rerun this 50-yard test with some lighter pellets that are known to be accurate. Someone asked me about that already, and I think it needs to be tested.

Finally, blog reader Tunnel Engineer asked me to try resting the TX on the sandbag close to the triggerguard and again out at the cocking slot. He wanted me to compare group sizes and point of impact with the 2 balance points. But the bag I use is very long and runs all the way from the triggerguard to the cocking slot, so I don’t see how I can do that.

TX200 Mark III: Part 4

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3

TX 200 Mark III
BB’s TX200 Mark III.

Today’s lesson is about sighting-in a rifle scope. I know that scope mounting and sighting-in seems daunting, but it isn’t as hard as you might imagine. In the last report, I sighted-in at 10 feet. Because I got lucky, it took just 2 shots to sight-in the rifle; and when I finished, I told you I was ready to try the rifle at 25 yards. I said, based on the results of my 10-foot sight-in, it should be on paper at that distance (actually it would be on target at any distance between 20-35 yards, given the TX 200′s velocity), but it probably wouldn’t be exactly where I wanted it. Today, we’ll find out if that prediction is correct.

Let’s get to it
So, I set up the bench and started shooting at 25 yards. I chose H&N Baracuda Match pellets because they were the pellets I used at 10 feet. If you forget what happened during the 10-foot sight-in, you really should read that report first to appreciate what’s happened here. A quick summary would be that I guesstimated how high above the bore the center of the scope is, and shot at a dot the same distance above the desired point of impact. Aiming at the upper dot, I was trying to get the pellet as close as possible to the dot beneath, which meant the scope would be shooting to exactly the point of aim (offset by the scope and barrel centers) when all trajectory was removed from the equation.

TX 200 Mark III sight-in target shot 1
The two dots are separated by approximately the same distance as the center of the barrel and the center of the scope. Aim at the top dot and hit the bottom dot. This is the first shot. After I adjusted the scope, the second shot went through the bottom dot.

Shooting at 25 yards
The first shot at 25 yards landed slightly above and to the left of the bullseye. I then shot 4 more that moved over to the right just a little. I took the center of the larger 4-shot group as the place where the scope was really sighted, and I adjusted from there. In all it took me far less than 10 minutes to sight-in this scope, even though I spread the reports over a period of 2 weeks.

TX 200 Mark III 25-yard target first group
The first 5 shots at 25 yards landed high and to the left, with the very first shot landing farthest to the left. I took the center of the main group of 4 to be the point of impact. From there, I adjusted the scope down and to the right.

Bear in mind that I do not want to hit the dot at the exact center of the bullseye, if possible. That’s my aim point; and if I destroy it, I have to guess where to hold the crosshairs.

First group
Now that the rifle is sighted-in, I shot the first 10-shot group at 25 yards with the stock rested on my open palm, next to the triggerguard. I got a fairly good 9-shot group, but I managed to throw one shot to the left. Nine went into 0.376 inches, but that one stray shot opened the group to 0.605 inches. I was moving around too much in the artillery hold, and I could see it through the scope.

TX 200 Mark III 25-yard target second group
Nine shots in 0.376 inches isn’t bad for 25 yards, but a stray shot blew the group out to 0.605 inches.

Second group
Stability seemed to be my problem, so I slid my off hand out to where I could feel the cocking slot on my palm. The rifle seemed to rest steadier, but the group doesn’t reflect that. Ten pellets went into 0.714 inches, which is horrible for a TX200. Obviously, this wasn’t the right hold for the rifle. And just as obviously — I was having a bad day.

TX 200 Mark III 25-yard target third group
Ten shots in 0.714 inches at 25 yards is hardly something to be proud of for a TX200. It’s more of an outstanding group from a Chinese breakbarrel.

Sometimes, a disaster (okay, maybe just a small setback) contains the seeds of discovery! Since I couldn’t hold the rifle steady enough to shoot a good group on this day, could I rest it directly on the sandbag and do better? We’ve been interested in the fact that some spring guns don’t seem to need the artillery hold. I already told you the TX200 is one of them. Perhaps, this was the day to find out.

For the next group, I rested the rifle in the long vee-groove in the top of my sandbag. The bag is so long that the rifle rests there without needing a rear bag for support. It was dead-steady when I sighted this time.

The results tell the story! This time, all the shots went to the same place. The group is very round and tight, at 0.336 inches. This is clear proof that the TX200 can be bag-rested when shot, and also that the rifle is incredibly accurate. I’ve shot even better groups with it in the past; but whenever I do things right, I always get good groups with this rifle.

TX 200 Mark III 25-yard target fourth group
Shooting with the rifle rested directly on the sandbag produced the best group of the day. Ten shots went into 0.336 inches, and the group is relatively round, to boot.

Notice that in today’s test only a single type of pellet was used. That kept things simple and allowed me to look at other things without worrying about which pellet to choose.

So, we’ve learned 2 things. The first is that it’s easy to mount a scope on an air rifle and to sight it in. It doesn’t take a lot of time, nor do you need any fancy equipment. Of course, if your rifle has a drooping barrel problem there will be more to do, but these are the basics.

Second, we’ve learned that the TX200 can shoot as well or better when rested directly on a sandbag as it can with an artillery hold. That’s certainly true if you’re shaking when holding the gun.

Tomorrow is the 50-yard test, followed by a full test of a brand-new TX200 Mark III, I hope. There are some other things that can be explored with this rifle as our testbed. All in all, we have a lot of things left to do with this air rifle!

Scope basics: Part 2

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1

Parallax
Parallax is an optical term describing how the point of view affects what the viewer sees. The driver of a car may see his speedometer needle at 60 m.p.h, while a passenger to his right may see it hovering just above 57 m.p.h. In the UK, the passenger is on the driver’s left and the speedo needle will appear to be over the 63 mp.h. mark. The needle hasn’t moved in either case, but the observer’s viewpoint has moved.

And so it is with a scope. You look through it and see the crosshairs exactly in the center of the bullseye; but if you move your head on the stock, the crosshairs will also appear to move slightly. So, where you hold your head relative to the scope determines where the scope appears to be “looking.”

Many scopes today have a parallax adjustment. Some scope manufacturers call this an adjustable objective, or simply AO; but that just stems from the fact that it is the objective bell that’s turned to correct for parallax. On other scopes, this adjustment is a knob on the left side of the adjustment turret.

09-27-13-01-adjustable-objective The adjustable objective is an objective bell that turns to remove as much parallax as possible. The scale on the bell indicates the yards to the target that have been focused.

09-27-13-02-sidewheel-parallax-adjustment On scopes with a sidewheel parallax adjustment, a knob on the left side of the turret adjusts for parallax. This is much easier to reach than the objective bell when holding a rifle.

The parallax adjustment adjusts the scope lenses so the least amount of parallax exists at that distance (the distance to the target). To the shooter, it looks like the scope is focusing on the target. But here’s the important point: No amount of parallax correction is ever enough. There will always be some parallax in the scope, no matter how well it’s been adjusted. Where you hold your head on the stock is very important, whether or not your scope has a parallax adjustment.

Range of scope adjustability
Every modern scope comes with vertical and horizontal adjustments, so the crosshairs may be adjusted to the point of pellet impact. Open sights often have these same adjustments. But there’s one big difference between an open sight’s adjustments and those of a scope. As an open sight is adjusted, the sight is moved mechanically. Usually just the rear sight moves, but sometimes the front sight moves, as well.

When a modern scope is adjusted, you cannot detect any movement. It’s inside the scope but can’t be seen from the outside.

What gets moved isn’t the scope tube, but a smaller tube inside the outer tube. This inner tube is called the erector tube, and it contains the reticle and other things. The wires or lines of most reticles do not move when adjustments are made. Instead, the entire erector tube moves, carrying the reticle lines with it. Since the lines are fixed, they always appear to be centered when you look through the scope.

There are some scopes that do have moving reticle lines. These are older technology scopes and are often from Germany or Russia. But these are so infrequently encountered on the modern market that they aren’t worth discussing.

I’ve mentioned the term modern in relation to the scope of today. Fifty years ago, there were scopes that did not contain erector tubes. Instead, these scopes were adjusted from the outside, so their entire tubes moved whenever adjustment were made. The adjustments were in the scope rings.

09-27-13-03-adjustable-scope-rings This vintage Unertl scope is held in spring-loaded rings that adjust the whole scope like the erector tube in a modern scope. The spring is inside the button at the 4 o’clock position and works for both the vertical and horizontal adjustments.

09-27-13-04-scope-turret The section of the modern scope that contains the adjustment knobs is called the turret.

By looking at vintage adjustable scope rings, we can see how the erector tubes inside modern scopes move when they’re adjusted. And this is what is important. The adjustments work against a coiled steel return spring that pushes the scope back when the adjustment screws are backed off.

When the scope is adjusted higher or to the right, the erector tube springs expand and lose their tension. At some point, which differs from scope to scope, these springs relax. That’s when the scope no longer holds a zero and won’t adjust in that direction anymore.

09-27-13-05-scope-knob-adjustment-range This scope’s elevation knob is adjusted as high as it will go. The erector tube spring is fully relaxed, and the scope will be free to shift. It would be better not to adjust this scope above the horizontal No. 3 line.

Quality scopes have more adjustment range than cheaper scopes, but all scopes have difficulty adjusting out to their upper and right limits. As a general rule, I tell shooters they should never adjust beyond the three-quarter point in the high or right directions.

People sometimes ask if there’s a problem when adjusting the other way (down or to the left), and I tell them there isn’t. All you do when you adjust all the way down or to the left is compress a coil spring until it’s coil-bound. That doesn’t damage the scope, nor does it affect accuracy in any way.

Scope sights are wonderful tools that can enhance your shooting experience. They’re not magic, however. They operate by rules, just like anything else. Learn how they work, and they’ll do their part to make your shooting more successful.

Scope basics: Part 1

by Tom Gaylord, a.k.a. B.B. Pelletier

This article was originally written for the upcoming Pyramyd Air catalog. But there were so many new rifles and pistols that we didn’t have room for this. I felt it was important enough to get it out, so I’m publishing it on the blog.

You’d like to have a scope; but when you check into the subject, it gets very confusing, very fast. In this 2-part blog, we’ll explore the basics of scopes.

A telescopic sight, or scope, is a type of sight that magnifies the target, usually making aiming easier. It may have a fixed amount of magnification or the magnification may vary within a range, allowing the shooter to select what he wants.

Inside the scope are lines called reticles. One runs up and down and the other runs side to side. They intersect in the center of the field of view. They are the aim point that’s put on the spot where you want the pellet to go. They adjust in both directions, but you never see them move. They are held inside a tube inside the scope; and when they’re adjusted, the entire tube moves so they always appear centered.

09-26-13-01-crosshair-reticle
Crosshairs

09-26-13-03-mil-dot-reticle
Mil-dot reticle

09-26-13-02-duplex-reticle
Duplex reticle

If your rifle is sighted-in, the pellet should land fairly close to where the intersection of the reticles was when it fired. How close it lands depends on several things—how accurate the rifle is, how well it was held when it fired, how good a pellet you use, the weather conditions (especially the wind) and so on.

The rifle is always moving!
The first thing that surprises someone who looks through a scope for the first time is that the rifle is always moving. In the movies, the camera sometimes looks through scopes that never move; but in real life, they’re never still. The rifle is also moving when you sight with open sights; but since the target isn’t magnified, you cannot see the movement.

Just because there’s a scope on your rifle doesn’t mean it will be more accurate. You have to find ways to slow the movement and to eliminate or minimize it as much as possible. Once you learn to do this and to follow through after every shot, you’ll be rewarded with better groups and more accurate shots.

More magnification may not help
You would think that because a scope magnifies the target it automatically makes it easier to see and hit. Sometimes it does, but other times it does the opposite. When the magnification is too great and the target area is dark, you may not be able to find the target in the scope. When you hunt in the deep woods, for instance, a 4x scope will do a lot better than a 16x scope. You may be able to see the veins on each leaf through the 16x scope, but which leaf are you looking at?

Greater magnification also can make the image seen through the scope darker, and it may even appear as though it’s in fog. On every scope that has adjustable power, the amount of light that gets through the scope decreases as the power increases. This effect is offset by superior quality lenses and by special lens coatings, but the budget brand scopes don’t have these things.

Magnification — use what you need
Why do airgunners need so much magnification? Well, most of them don’t need it, but one group does. The field target shooter uses his scope to help determine the range to the target, so he can know where his pellet will be in its trajectory when it arrives on target. The difference of a yard or two can make the difference between a hit or a miss.

A field target shooter wants to see the smallest object he can possibly see at the farthest distance on the course, which is 55 yards. He’d like to be able to see a blade of grass so clearly at 55 yards that when he adjusts the parallax he can see the image come into sharp focus. If that blade of grass is standing next to the target he wants to shoot, he’s just determined the range to the target.

It takes a lot of power to see a blade of grass clearly at 55 yards in a dark forest setting. So, field target shooters use scopes of 32x, 40x and even 60x to resolve things this small. These scopes aren’t too useful for most shooting; but for the rangefinding task, they excel.

Most airgunners will do very well with 9x, 12x and even 16x. Scopes of that power will be smaller and lighter, and that translates to less fatigue while hunting. A squirrel hunter in the deep woods can get by with even less power. Maybe 6x is all he needs. Benchrest target shooters, on the other hand, have a stable platform and can spend some time finding the target in the limited field of view that a powerful scope gives. For them. the most important thing is being able to bisect the target as precisely as possible, so every shot is aimed at the same place. Understanding what magnification you need and matching it to your sport is one of the things that increases satisfaction when shooting airguns.

Understanding scope adjustments
Most shooters know there are both vertical and horizontal adjustments available on a scope. They’re called elevation and windage adjustments. Here are some facts about adjustments that you may not know.

First of all, no scope adjusts exactly by a quarter minute of angle or an eighth minute of angle. When they say these things, scope manufacturers are only making approximations. The scope adjustments depend on the thread count of the adjustment screws, and the manufacturer will round this up or down to give an approximate distance the crosshairs move. This is given in minutes of angle, and the most common understanding is at a 100-yard distance, where a minute of angle is very close to one inch. So, a scope with ¼ MOA adjustment clicks is supposed to move the point of aim by a quarter-inch at 100 yards. It sounds great until you understand that everything is an approximation. The real distance that the crosshairs move with one click of adjustment may be 0.311 inches, but no scope manufacturer is going to put that on the box. So, they write that the scope has quarter-minute clicks, and you work it out when you sight in — unless you’re anal, which is where some shooters get into trouble.

These shooters arrive at the range with their scoped rifle and a notebook to record all the scope adjustments. Man — that is a heartbreak in progress! What will happen, if they stick to it long enough, is that they’ll discover that their scope actually adjusts by 7/19 of an inch per click. Most of them see the futility of trying to do it by the book and default back to adjusting the scope until their rounds strike the paper where they want them to…or as close as their scope can come.

Stiction
Now, let’s talk about stiction, which is the scope’s unwillingness to move after being adjusted until it is hit with a large amount of vibration. Said plainly, the scope tends to stay where it was before the adjustment until the gun is fired several times and it finally “settles in” to the new adjustment. Put an eager-beaver shooter on that scope and have him try to sight it in, and you have the recipe for disaster. He’ll keep adjusting the knobs, all the while the scope is lagging behind each adjustment by two or three shots. The result will be a scope that wildly changes its point of impact as the frustrated shooter fails to comprehend that he’s causing the problem.

09-26-13-04-Stiction-target
When a scope is adjusted, sometimes it takes several shots for the adjustments to be fully realized. This is called “stiction,” which is the resistance of the scope’s parts to movement after they’re adjusted. In this case, the first shot was to the left and low, where the scope had been before adjustment. Shot 2 moved to the right and up, and shots 3 through 5 are in a tight cluster in the new point of impact.

Not all scopes suffer from stiction. Of those that do, all won’t suffer by the same amount. Each scope must be taken as a unique entity, and the shooter has to have patience when adjusting it. This is the one time where three-shot groups are valid because they give the scope time to move to the new setting. But if the shooter doesn’t realize what’s happening, it can look like the scope is no longer able to hold a group because a three-shot group from a scope with a lot of stiction will look like a wild pattern. All you have to do is to continue shooting the gun, and things will settle down, again. But some shooters don’t have the patience for this.

Look for part 2 tomorrow.

TX200 Mark III: Part 3

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2

TX 200 Mark III
B.B.’s TX200 Mark III

As you read this, I’m driving to the Roanoke airgun show. This is just a reminder that I’d like you veteran readers to help answer the questions we get from the new readers while I’m away from my desk. I’ll read the comments a couple times each day and answer those I need to, but I don’t have as much time when I’m on the road. Thanks!

Today, I’ll mount a scope on the TX200 Mark III and sight it in. This is normally accuracy day, but I’m slowing down this report so I can explain several things that are usually glossed over — such as mounting a scope and sighting-in.

This report will look like a photo gallery. And the photos were all taken with flash because there are so many of them. I apologize for that, but I have examined each picture and you will be able to see each thing I refer to.

Let’s get started. Someone said I should used the Hawke 4.5 to 14 X42 Tactical Sidewinder scope, so that is what I mounted. I used a set of Leapers 30mm medium-height rings because they’re high enough for this scope and have the vertical scope stop pin that the TX200 needs.

Does the scope fit the rifle?
The first step in the process is to lay the scope next to the gun, positioning the eyepiece where you think it needs to be to fit your eye position. That will tell you how the scope is going to fit on the rifle.

TX 200 Mark III fitting the scope
Laying the scope above the rifle where the eyepiece needs to be tells us how the scope will fit on the rifle. Notice that the objective bell will hang over the loading port a little; but as I mentioned in Part 2, that’s not a problem.

Seeing that the scope will fit, the next task is to position the scope rings on the rifle. I used 2-piece rings, so I will first position the rear ring with the scope stop pin. The TX200 Mark III has three holes for a vertical stop pin. Pick the hole you like and make sure the stop pin fits into the hole when the ring is installed.

TX 200 Mark III scope stop holes
Pick one of the 3 scope stop holes to receive the vertical scope stop pin in the bottom of the scope ring.

TX 200 Mark III scope stop pin
Adjust the vertical scope stop pin in the base of the rear scope rings so it goes deep into the hole on the rifle. On some rings, it will be necessary to peel up the anti-slip tape to access this pin for adjustment.

Now, you can mount the rear scope ring, making sure that the stop pin goes into the hole you’ve selected. Try to slide the ring to the rear of the gun so the stop pin makes contact with the rear wall of the stop hole. Then, you can tighten this ring in place.

TX 200 Mark III scope ring mounted
Attach the rear scope ring to the rifle, ensuring that the stop pin is pressed against the back wall of the hole in the rifle. Tighten the screws on the ring base when you’re satisfied.

Once the rear ring is positioned, you can position the front ring, using the scope as your guide. Leave room on both sides of both rings to slide the scope back and forth, if possible. This is where the advantage of 2-piece rings shows up.

TX 200 Mark III front scope ring mounted
Now the front scope ring may be installed, using the scope as your guide. Leave room to slide the scope back and forth, if possible.

Once both ring bases have been installed, carefully lay the scope in them and see how it fits the rifle.

TX 200 Mark III scope trial position
The scope is now laying in the rings. Notice that it does overhang the loading port by about as much as we estimated earlier.

Now that I know the scope fits as planned, I check it for fit with my eye by holding the rifle in a shooting position. The scope is still just laying in the bottom rings — the caps haven’t been attached yet.

TX 200 Mark III scope trial position for the eye
By looking through the scope, I determine that the rings have been positioned correctly. I adjust the scope slightly to align the vertical reticle and also to position the eyepiece for maximum light when the rifle is held comfortably. The caps can now be installed and secured.

TX 200 Mark III scope caps secured
The caps are secured.

Aligning the scope
You can go through all kinds of machinations to align the scope perfectly vertical, but it doesn’t matter. What matters is that it looks vertical to you when you hold the rifle comfortably because that’s the way you’re going to align the scope every time you use it.

I used to do all sorts of things to “level” the scope before I finally understood that the scope will NEVER be level! Level is what looks level to you; and if you hold it the same way every time, that’s all that matters.

Sight-in
Now that the scope is mounted, it’s time to sight it in. For that, I made a white card with two black dots made by a felt-tipped pen. The top dot is my aim point and the bottom dot is as far below the top dot as the center of the bore of this rifle is below the center of the scope. That was just a rough estimate — I didn’t use a ruler. I’m going to sight-in the rifle at 10 FEET. That’s right — 10 FEET!

If this seems strange, you haven’t read my article about a 10-minute sight-in. When I worked at AirForce Airguns, I used to mount scopes and sight-in all the rifles that were sold directly by the company. It took less than 30 minutes from the time I was told what rifle and what scope was needed until I had the scope locked down and sighted-in at 23 yards. This procedure is how I did it so fast.

I step back about 10 feet from the card with the 2 dots and put the crosshairs on the top dot. I fired one shot. I used H&N Baracuda Match pellets because I know they do well in this rifle.

The first shot lands slightly high and to the right of the lower dot. Remember, the lower dot is where the pellet should go if it comes straight out of the barrel while the scope is aimed at the top dot.

TX 200 Mark III sight-in target shot 1
Shot one is a little high and right, but it’s not too bad. I adjust the scope left and down from this.

Shot 1 was a surprise. Usually the first few shots are a lot farther off the mark than this. But I adjusted the scope from this — left and down.

How much left and down is not a precise thing. I do it by spinning both adjustment knobs and not even counting the clicks because I know that at 10 feet I have to move the crosshairs a lot to make them move at all. If I had to guess, I would say it was 16-20 clicks on each knob. Then, I fired the second shot.

TX 200 Mark III sight-in target shot 2
I enlarged the view so you could see the second shot. It went exactly where I wanted it to go.

Now, the rifle should be on paper and close to on-target at 25 yards. It may not be exact because this is a loose method — but it will be close enough.

Next time, I’ll shoot 25-yard groups, and I’ll start with where this sight-in lands me.

Why do airgunners need high-magnification scopes ?

by Tom Gaylord, a.k.a. B.B. Pelletier

Today’s report is for blog reader J-F, who asked this exact question: “Why do airgunners need high-magnification scopes?” And let’s define high magnification as anything over 12x. That’s arbitrary, of course. It’ll be arbitrary no matter where you set the limit. I set it there because that’s 3 times the power that the average deer hunter’s scope had in the 1950s.

But airgunners delight in 24x, 32x, 40x and even 60x scopes. I know because I’m one who does. But I also know why I want this level of magnification and what purpose it will serve.

Braggin’ rights
One reason for high-magnification scopes is pure bragging rights. Like the pilot who has to have the largest, most complicated watch, the biggest scope gets the most attention — at least in the minds of the guys who think that way. And I know for a fact that some people do think that way; I’ll tell you how I know in a moment.

Field target
One good reason for owning a scope with high magnification is so you can use it to determine the ranges to targets. No one needs to do that more than the field target competitor. Rangefinders are not permitted in field target matches, but the parallax adjustment on a scope provides something very close because it focuses the scope when the distance to the target is dialed in. This isn’t a true rangefinding function like you might find on a coincidence rangefinder built especially to do this, but it’s close enough to satisfy most people. And, it’s all you’re allowed to do.

Field target courses run from 10 yards to 55 yards, so the scope has to work in those boundaries. You want a scope that has most of its adjustment range between 10 and 50 yards. The best field target scopes are made that way — with 3/4 of the adjustment (the distance that the adjustment wheel or bell is turned) between those 2 distances.

To determine ranges accurately, you have to be able to see when something very small comes into sharp focus at your desired distance. To see things that small, you need as much magnification as you can get with the image still being clear.

field target
The kill zone of this field target is the small hole above the dime. Your pellet has to go through the hole without touching the sides to score a point. This is why field target competitors need to know how far away the targets are!

Let’s get something clear right now. Just because a scope adjusts to 40x does not mean that you can use it at that setting. I own a Tasco Custom Shop 8-40X56 scope that cost $650 back in the 1990s, and it’s unusable above 30x for anything other than a bright target in direct sunlight. Field targets are often shot in the deep woods, where the light is either low or dappled with bright sun and dark shadows. In that light, my Tasco isn’t useable above 30x.

There are cars whose speedometers go up to 120 m.p.h. It doesn’t mean the cars go that fast. Same is true of scope magnifications levels. If you want to see at 40x in a field target setting, you’re probably going to have to pay close to a thousand dollars for your scope.

Small field of view
Here’s how I know that some people buy big scopes just to be envied. On several occasions, I’ve seen a field target competitor start the match and then not be able to find the targets! They sit there burning everyone’s time, looking though their powerful scopes but are unable to see the targets because everything looks so big and dark through the lens. This got so bad, in fact, that AAFTA (the American Airgun Field Target Association) started enforcing the time rules that typically give a competitor 5 minutes per 2-target (4-shot) lane.

The reason this happened is because these guys had never looked through their scopes at anything besides paper sight-in targets until the day of the match. They assumed things would be as they always were; and, of course, they aren’t when you move from a well-lit range into the woods.

The other thing powerful scopes do is bring out the anal side of some shooters. They will sit and range and rerange to the target, acting like some clueless manager examining a spreadsheet. They can’t get off the dime and take the shot because — what if they were wrong?

On the other hand I suffer from the opposite affliction. I don’t take my time and just charge on through the course. Great instincts for a first-wave armor officer — not so good for longevity on the battlefield or to win a match.

Benchrest shooters
The other shooter who really needs a powerful scope is the benchrest shooter. “Aim small, miss small” is their motto. A few weeks back, I showed you my 100-yard box targets that help me sight my most accurate scoped rifles.

printed box target1

My best centerfire rifles are, in descending order — my Rock River AR-15, which I built from parts; my HW 52 in .22 Hornet; and my Savage 1920 bolt-action in .250-3000 Savage. The AR has the Tasco 8-40X56 scope on it; and even on sunny days, the power never goes above 30 or the scope gets foggy. The Weihrauch Hornet has a vintage Weaver K10-T that’s a fixed 10-power scope with an adjustable objective. The Savage is carrying a vintage Weaver V9-W 3-9X32 variable with a widefield view.

three rifles
My 3 most accurate centerfire rifles are (from the top), AR-15, .22 Hornet falling block and .250-3000 bolt action.

One of the main reasons two of these scopes are vintage is that they have fine reticles that are perfect for my box targets. I can see when they split the box, even at these relatively low magnifications. Would I like more power? You bet! But I need to get it in scopes that will fit in fairly exotic rings and clear the guns when they’re mounted. That’s a tall order because high magnification usually comes with a large objective bell.

Who doesn’t need high magnification ?
As a general rule, hunters don’t need high magnification; and they do need the wider fields of view and brightness that come with lower-powered scopes. Varmint hunters might disagree with me on this because they’re more like benchrest shooters, but squirrel and rabbit hunters will probably agree.

Exterminators can also get by with lower power, with a few exceptions. When they hunt quarry that’s extremely wary, such as rats can sometimes be, they may want more power to place their pellets precisely on the little part of the animal that does show. But we’re talking 12-16x here — not 40! But the guy who’s killing birds in a discount store or mall at 3 a.m. can get by with a good 6x scope most of the time.

So, J-F, the answer to your question is a combination of things. There are those airgunners who actually do need high magnification, then there are the wannabes who have it because it’s cool. And then there are the first-time buyers who may get it because they have no idea what they’re getting into, and high magnification sounds good.

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