Target Sports

SCOPE MOUNTING GUIDE: ALL SCOPED UP

Created on 14th May 2009

MARK CAMOCCIO explains the best way to mount your scope to your rifle

THE MAJORITY of airgun shooters will fit some form of telescope sighting device or scope (often termed a ‘telescopic sight') to their rifles today, and a fantastic array of dedicated products is available to meet that demand. This choice is now accompanied by a real upgrade in many of these products and very attractive prices. It's fair to say that, with regards to our shooting sport, we have never had it so good in terms of the sheer choice of products available. Scopes exist to satisfy every budget level, but whether you're fitting an entry-level bargain basement model or a Schmidt & Bender top-end piece of glassware, one thing is for sure: mounting the whole combination correctly will pay dividends in the long run.

Quality

I'd start by recommending that you buy the best mount you can afford, and bear in mind that there's often only a few pounds between British-made quality sets and some of the alternatives. Why pay out for a quality outfit only to scrimp at the final hurdle? After all, it's the mounts that actually connect the scope to the rifle, and if badly fitting parts result in alignment issues this can lead to despair and frustration.

I would also think carefully before using mounts with cloth/sticky padding inside the rings. In my experience padding is completely unnecessary, and often results in gummy residue sticking to the scope tube. While the idea of the padding is to prevent any marking of the scope tube, I don't consider this to be an issue if the correct fitting procedure is adhered to, as I'll explain in more detail below. The gum, however, is often very stubborn and tricky to remove - surely defeating the object of this design feature in the first place.

Have a rest

Any setting up procedure is best carried out with the rifle snugly positioned in a cradle or rifle rest, such as the popular MTM workbench rests (01977 681639), or Deben's Pro-Bench Rest (0870 442 2600). A classic cheaper alternative is the Cleaning & Maintenance Cradle, also from Deben, which is a satisfyingly simple and effective product. These rests obviously aren't vital, but to my mind they're an investment and make this, and any other maintenance job so much easier and more enjoyable.

Springers

Spring powered air-rifles, because of their fairly violent and unique two-way recoil, should ideally be fitted with a one-piece mount. This sees both scope rings joined by a solid base, which potentially provides a far greater grip. With the base clamp on this type of mount one continuous claw, the increased contact surface should make all the difference.

Another more advanced solution is also available for those who want maximum protection for their treasured glassware. With the aforementioned recoil of a spring-powered airgun, it was only a matter of time before someone devised a more protective mount that would shield the scope from most of the shock. That two-way snap as the piston flies down the compression cylinder, ‘bottoms out' and whips back from where it came is a comparatively violent action. What the Dampa one-piece mount does is provide a two-part base, which, through the use of rubber bushes, absorbs much of the recoil, thereby transmitting less to the scope. The Dampa is available from both Theoben and Sportsmatch, and I can certainly vouch for its quality.

If all this is seen as overkill, or the additional weight of one-piece units (albeit slight) is to be avoided, two-piece mounts can still be used but some form of arrestor system needs to be included in the set-up.

Arresting recoil

At this point, if the mounts have a built-in arrestor stud protruding from the underside this could either prove to be ideal, or have to be dealt with. The stud is intended to fit into a pre-drilled hole on the rifle's receiver/cylinder, yet if the rifle has no arrestor holes then the stud needs to be screwed up into the mount body and out of harm's way - normally simply done using an Allen key. Some designs, including Sportsmatch mounts, use a recoil pin which, not being threaded, needs to be tapped into the base. While I'm a huge fan of Sportsmatch mounts and use them on my competition rigs, I do wish the firm would use the threaded version as taking a small hammer to the mount is a worrying business. However, if the pin is present in your mount and it doesn't line up with any holes in the rifle's action, then the procedure to neuter it is as follows: remove the top part of the mount ring, then lay the mount inverted onto a firm surface (making sure it will not become marked) and, using a punch or suiably sized tool along with a small hammer, gently tap the pin until it is flush with the base.

If the recoil pin isn't used then the kick from a spring gun can still be tamed with the use of an additional arrestor block. These are small blocks which clamp in the usual way to the rails and sit snugly up behind one or both mounts, restricting their movement. One block situated behind the front mount should suffice.

De-grease

Again, because of the recoil, it would make sense to give the mounts a good start in life by degreasing the scope rails on the rifle. Normally just taking off the excess oil with some tissue paper will suffice, but if scope ‘creep' becomes an issue (where the mounts actually move back along the rails after a number of shots have been fired) then a de-greasing solution, used sparingly, may become necessary. Just gently squeeze the tissue into the track of the rails and move it along the length until any residue is removed.

Mounting procedure

Pneumatics are a different animal - or less of an animal, I should say. With their near-recoilless action they impart little or no stress to the scope, so mounting is a far more civilised and relaxed affair. The following procedure, however, applies to any rifle set-up when using conventional-style mounts.

If two-piece mounts are to be used, start by unscrewing the tops of the rings on each mount, being careful to note the corresponding screws and positions. It makes sense to make sure the ring top is replaced in exactly the same position as it was removed, so the screws and threads all match up - threads can occasionally prove very stubborn!

Back to the task in hand. With the tops of the rings removed, slacken off the mount base screws without removing them and gently fit the mounts to the scope rail in roughly their chosen position. Only finger-tighten the side screws at this stage, as everything will almost certainly be fractionally adjusted further down the line.

Reversible clamps

As an aside, it's worth noting that most modern scope mounts have a reversible side to the bottom clamp, allowing for a variety of scope rail dimensions. If the clamps don't actually grip the rails, even when tightened, try reversing them and if everything looks aligned and sits evenly, you're in business.

Now offer up the scope to the mounts and loosely fasten the tops of the rings into position, making sure the screws are all gently nipped-up in alternate sequence - much in the same way as car wheel nuts. The idea is to spread the pressure, so gently nip up front left, then back right, then front right, then back left. Then keep repeating the process. If the mounts have double clamps, take this into account. At this stage the idea is to get to the point where the scope is held with some gentle resistance yet can still be rotated. Double-check that the side clamps are reasonably firm on the rails so the scope won't fall off when the rifle is held while sighting up!

Always do things gradually, checking as you go. Never over-tighten the screws or ‘bottom out' on one side before tightening the other side. The aim is to produce a correctly aligned and well centred scope that is not under stress. If there are any signs of misalignment, as can occasionally happen with the machined grooves in less expensive guns (though thankfully this is rare today), then tighten no further until you are sure all is well. With the bottom mounts firmly attached the scope tube should be a snug fit and should not need excess pressure to make it fit the radius; if one end slips in easily and the other is reluctant don't force it, check everything is aligned.

The small screws that clamp the scope in the mounts can supply a surprising amount of pressure and we don't wish to mark (or worse still misalign) the scope body tube.

Eye relief

At this point the correct eye relief now needs to be set - that is the distance between the eye and the scope where a full crisp sight picture is achieved. The shooter's most common shooting position should be adopted. The trick here is to close the eyes; mount the rifle in a normal comfortable manner; open the eyes and note whether the head has to be moved nearer or further away from the scope, and by how much.

The scope can now be moved accordingly. Ideally the mounts should be as wide apart as possible to hold the scope most effectively, but loading ports and other features may restrict the final positioning. An obvious restrictive factor to scope positioning is a break-barrel action. On this type of rifle make sure that any large scope isn't fouling the breech area before the rifle is cocked - sounds obvious, but it's easily done!

A combination of gently sliding the scope within the mounts and moving the mounts up and down the rails should hopefully allow the desired position to be reached. This is where having everything only loosely fitted (yet not sloppy) should allow the flexibility to achieve that vital final position. Don't rush this part, as achieving a comfortable, near stress-free shooting position, where your eye is easily aligned with the scope when your head is comfortably on the stock with the reticles clear and sharp, is about as fundamental as it gets. If the scope rails or dovetails appear to be too short, then ‘reach-forward' mounts may just solve the problem. These typically allow the front mount to be placed a further 25mm forward of the rails, which is often enough. Sometimes you might prefer these mounts anyway as they give greater rigidity by gripping the scope further forward.

Once correct eye relief has been set, the scope needs to be carefully rotated until the crosshair is perfectly level in relation to the rifle. This can be done by eye if you feel competent enough; otherwise, a plumb line and brick course on a building may be enough to give an idea of true vertical and horizontal. Again, take your time here, as any error in the alignment of the reticle will almost certainly cause some cant in the shooting position: this will inevitably set up error after error in trajectory and cross-over down range.

Once the scope picture and alignment is satisfactory all the screws can be fully tightened, again by gentle increments and in sequence. The scope is now ready to be zeroed.

While the above deals with most fairly conventional airgun mounts, variations in product design do exist and BKL mounts are an interesting example. These high-quality mounts are manufactured in the United States and feature an unusual fixed base clamp. They are supplied to fit particular rail measurements but the bottom clamp still needs to be finely adjusted. This is done by removing the socket-headed fixing screw and screwing it into the empty hole on the other side. This forces the clamp jaws slightly apart, and allows the mount to be slid down the rails into position. It then remains for the screw to be returned to its original side and the clamp nipped up. Thereafter the above scope mounting procedure would apply. These mounts can seem a little expensive when compared to some, but the standard of finish is excellent.

The next article in this series will take you through a basic zeroing regime and deal with problems which may arise along the way.