Tips for better accuracy from spring piston airguns.
Stock screws that have worked loose are probably the most common cause of inaccuracy in spring piston airguns. Even a quarter turn loose can translate to significant increase in group size. Most airguns have one or two screws at the front of the forearm and one securing the action to the stock near the trigger (often one of the trigger guard screws). These must be tight at all times with any lock washers in place. We recommend checking the tightness every 100 rounds or every year which ever comes first.
Barrel pivot screws that have worked loose screws on the front of the compression tube will also affect accuracy on break-barrel models.
Airgun slotted screws, are different from hardware store screws. They require special screwdrivers with a parallel not tapered tip. Use of a regular screwdriver can damage the screw head, the gun, or yourself. Don't over tighten! Any more tension than firm will probably compress the wood fibers and damage the stock, particularly the forearm screws.
Open Sights - check that the front sight screw is tight and the sight element held within is secure. Check the rear sight for play.
Scope Mounts For best results and to prevent damage to your scope and airgun you should use a scope mount specifically designed for airgun use. These may have an integral scope stop pin that locates in special arrestor holes milled into the receivers of the some air rifles. Unlike a firearm, spring piston airguns jump forward and vibrate. Separate scope stops should be used if the scope stop is not an integral part of the scope mount. Scopes can also move through the scope rings but this problem is usually eliminated using the right scope mount.
Incorrect Barrel Tension:
Break barrel airguns must have the barrel pivot screw tension set correctly. Too much tension and the barrel detent will not consistently lock up and there will be galling of the breech block. Too little tension and there will be blow by at the breech. Incorrect barrel pivot screw tension can cause larger then normal shot groups. The correct tension is the point where the barrel will just stay anywhere on the return arc after cocking.
Most inaccuracy queries emanate from owners of .177 magnum sporters rated muzzle velocities of about 1000 fps or more. Many manufacturers use the very lightest pellet available to achieve their advertised velocity. You must determine the best pellet (brand, shape, and weight) for your particular airgun. Every airgun is different and what works for one airgun doesn't mean it will work on another airgun of the same make and model. Don't use old and oxidized pellets or any deformed pellets. Deformed pellets can allow the piston to hit too hard, risking damage, or get stuck in the bore. Only use high quality lead pellets from reputable manufacturers. Cheap pellets are false economy.
Airguns barrels accumulate fouling, but not in the same manner as regular firearms. Instead minute traces of lead and the airgun's lubricants from the compression chamber deposit in the rifling. This must be carefully removed by proper airgun barrel cleaning. We strongly recommend a flexible rod or pull through to avoid damaging the delicate crown or rifling.
Don't use regular petroleum based lubricants, gun oils, or firearm solvents because they will attack the seals. Use a gentle degreaser on a cotton patch and make sure the bore is dry before applying a very light coat of polarizing oil to protect against rust. A good quick fix in the field is to use "Quick Clean" felt pellets which are fired through the barrel every 500 shots, box of ammo, or yearly. On any airgun with greater than match velocity, use multiple Quick Clean pellets.
Hold your airgun loosely against your shoulder and let it jump around when you fire it. Don't pull it in hard into your shoulder and don't rest the forearm on anything. Let it recoil and vibrate freely. Because this recoil and vibration occurs while the pellet is still in the bore you must hold your sight picture just a little longer to get the smallest groups possible. Trigger squeeze, breathing, and stance are more critical then when shooting a firearm.
If have followed all these suggestions and still have accuracy problems your airgun may need the attention of an airgunsmith. If you disassemble your airgun you will void your warranty! From experience it is far better and cheaper to have an experienced airgunsmith do any service.