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.