by Tom Gaylord
Writing as B.B. Pelletier

Hatsan Bullmaster
Hatsan Bullmaster semiautomatic bullpup PCP.

Part 1
Part 2

This report covers:

  • Mounting the rings
  • Problem
  • Enter BKL
  • Two strap rings
  • More to mounting a scope
  • Shim the rear mount
  • Position and level the scope
  • Adjust the eyepiece
  • Thickness of the reticle lines
  • Is this scope clear?
  • Scope mounted — what’s next?
  • Summary

Today is Part 3 of my report on the new Hatsan Bullmaster precharged pneumatic airgun, but you may recall that I introduced two new products in Part 2 — the new UTG 3-12X32 AO Bug Buster scope and some UTG Accu-Sync scope rings that are so new they aren’t even on the Pyramyd Air website yet. Normally in Part 3 I start testing the accuracy of the airgun under review, but today I’m going to discuss mounting this new scope and getting the rifle set up to test. With all the new readers that have joined us over the past several months it seems like the right thing to do. Let’s get started.

Mounting the rings

Step one will be to mount these new rings on the rifle. Hatsan has made this very easy by providing a scope base that accepts both 11mm airgun scope rings and Picatinney/Weaver rings. The Accu-Sync rings I’m mounting have Picatinney bases, so they should be easy to mount — except for one thing. Bug Buster scopes have very short tubes that the rings attach to, so the position of the rings, fore and aft, is critical. Picatinney bases have cross slots that can cause a problem for fore and aft positioning. Let’s see how this goes.


Right away there was a problem. The UTG rings have lugs that are 5.02mm wide, which should fit into the cross slots of a MIL-STD (military standard) 1913 Picatinney (STANAG 2324) rail system. The bases on the test Bullmaster have cross slots that are 4.86 mm wide, which is undersized for the lugs of a Picatinney mount. Picatinney cross slots are a minimum of 5.23mm wide. So, even though it looks right, the base on the BullMaster I’m testing does not meet the MIL STD and cannot accept the UTG Accu-Sync MIL STD rings. Boy — am I glad I decided to report this for you! Weaver rings that have 3.5mm lugs will fit on the Bullmaster rail fine, but not Picatinney rings.

Enter BKL

The Bug Buster scope came with medium height rings of its own that I could have used, but because this is a bullpup, high rings are better. When something like this happens I reach for some high BKL scope rings that attach to an 11mm scope base by clamping pressure, alone. Fortunately the BullMaster also has a dovetail that’s 11.57mm wide.

Hatsan Bullmaster scope rail
The 11mm scope rail dovetail on top came into play because the cross slots in the rail below are not cut to the MIL STD.

I selected BKL 263 MB 2-piece high scope rings for this job. Whenever you mount a compact scope, and especially when it’s a Bug Buster, you can only use 2-piece rings because the positioning of each ring is so critical. One-piece rings are a fixed distance apart, and it’s usually a distance that does not coincide with your needs. Because of the Bug Buster scope’s short tube on either side of the turret, the rings have very little fore and aft leeway.

Two strap rings

BKL did something clever with the top strap of the ring. Instead of making it a wide single strap, they put two separate straps on top of each ring. This is clever because it releases you from the need to torque the strap screws in a certain pattern to keep from putting uneven torque on the scope tube.

Hatsan BullMaster scope straps
As you can see, the BKL scope straps are separate, even though they are on the same ring. This decreases the importance of torquing each strap the same, though you do still want to be close.

More to mounting a scope

There is more to mounting a scope than just putting it securely on the rifle. The eyepiece needs to be located at the correct distance from your sighting eye. On many spring rifles Bug Busters are hard to position correctly, but the Bullmaster has a long scope base that makes it easy to find the right place.

Shim the rear mount

Whenever I mount a scope on any air rifle I have never shot before, I always put a shim under the scope — on the bottom saddle of the rear ring. That little bit of shimming tilts the scope slightly down in front and usually compensates for any droop the rifle may have. I use a piece of expired credit card, which is a thicker piece of plastic than what you get from a 2-liter soda bottle. Don’t use two of these credit card shims; one should be plenty. If you need more than that, shimming is not the answer. You need an adjustable scope mount.

Position and level the scope

Positioning means to place the scope far enough from your sighting eye that the image looks full and clear to you. Leveling means the reticle lines are level with the gun. There is just one problem with that. There is no way to tell when a rifle is level, because level has no concrete meaning. The best you can hope for it to adjust the scope so that when you hold the rifle the reticle lines appear level. If they don’t, they will bother you as you shoot. The gun will be just as accurate, but when you adjust for windage, the strike of the round will also move up and down as it goes left and right. And when you adjust the elevation the round will also wander left and right. This is why some rifles shoot a little to the right at 20 yards and a little to the left at 40 yards.

Some shooters get anal over “leveling” their scopes. They hang plumb lines at 50 yards and adjust the scope in the rings until the vertical reticle is parallel to the line. I used to do that, until I realized that it doesn’t make any difference.

You can worry about leveling as much or as little as you want. At the end of everything you must be satisfied that the scope is mounted correctly.

Adjust the eyepiece

After I get the scope positioned and leveled, I adjust the eyepiece so both reticle lines appear as one solid line. That will make your parallax adjustment come out as close to the yardage indicated on the AO scale as possible. If you don’t do it the indicated yardage can be off by 20 yards. That defeats the rangefinding capability of your AO scope. Of course a 12 power scope really isn’t an effective rangefinder, but having the reticle lines solid also makes aiming easier.

Hatsan BullMaster scoped
The new Bug Buster scope compliments the small size of the BullMaster.

Hatsan BullMaster scope detail
This closeup shows just how short the Bug Buster scope tube is. Once the scope is in the rings there is almost no room to move the scope fore and aft.

Thickness of the reticle lines

Bug Buster scopes in the past have had very thick reticle lines. In the scope I am testing the lines are medium width. They are thick enough to pick up easily in the woods, but too thick for shooting quarter-inch groups at 100 yards.

The Bug Buster reticle is a duplex pattern, meaning the lines are thick at the edges and fine in the center. This is what a hunter wants, because the thick lines point to where the thin lines are, and in deep woods that’s what you want. The thin lines have mil dots that are spaced one mil apart, if you are into rangefinding with the angular measurements they provide. I use them as alternate aim points when shooting at different distances, which is fairly common.

Is this scope clear?

A reader commented that he didn’t think a 32mm objective is large enough for 12 power magnification, and the scope will not be bright as a result. I could tell you that it looks bright to me, but that’s just the other side of a subjective argument that can’t be proved either way. I think I need to get to the range and see how it performs on 50-yard targets to have a better way of evaluating the brightness. At my range the 50-yard targets are often dim and hard to see in the early morning, so this should be an acid test.

Scope mounted — what’s next?

After I mount a scope I like to check the rifle for zero at 12 feet on a target. I can tell from where the first pellet strikes the target if I will be on target at 25 yards for the accuracy test. My plan is to begin shooting with the H&N Baracuda pellets Hatsan sent with the rifle, so that’s what I will use for this.

The first shot landed at the right height but over to the right. I adjusted the scope and shot two hit to the left. So I dialed the scope back halfway and the third shot landed close enough to the center that I can accept it. A shots from 18 yards put a pellet about 5 inches higher than the aim point. That’s on paper at 25 yards in three shots (plus a check shot).


When I started today’s report I didn’t know how much material there would be, but it turned out for the best. I got to walk you thorough the process of getting a rifle ready for an accuracy test. And, because of the problem I had mounting the scope rings, there was even more to cover than I thought. The rifle is now ready to shoot for accuracy and I will do that tomorrow.