Inaccuracy in Air Guns
Posted: Tue Jun 21, 2011 2:00 pm
Hi Guys,
Here's some 'GYAN' I wish to share - especially for those who are getting initiated into Airgunning as a sport.
www.air-rifle.net/inaccuracy/inaccuracy.html
Air Gunners frequently complain that "I can't hit the broad side of a barn." Invariably, the frustrated owner has "tried everything, but it still won't give a decent group no matter what!"
Unfortunately, the information supplied with most new Air-guns is fairly ordinary at best and won't offer much assistance, so here is a list of the frequent problem areas to look at before you give up in despair. Most of this information applies to conventional spring piston Air-guns.
LOOSE STOCK SCREWS
This is probably the most common cause of inaccuracy in Air-guns. Even a quarter turn loose can translate to 50mm difference at 25 meters. Most Air-guns have three blade or Phillips head screws securing the action to the stock - two in the forearm and one through the trigger guard. These must be firmly tight at all times with lock washers in place. Loose screws on the breech-block assembly will also affect accuracy on break-barrel models.
CAUTION!
Before you run to your tool box – Air-gun slotted screws, are different. They require special screwdrivers with parallel tapers unlike carpentry screws. Use a regular screwdriver and you risk damaging the screw head, the gun and yourself-sometimes irreparably! We offer the handy and compact Gunsmith Screwdriver Kit that covers most of the screws you will encounter on your Air-guns including Phillips heads. Don't over tighten! Any more tension than firm will probably compress the wood and destroy the stock, particularly in the forearm.
LOOSE SIGHTS
Open Sights - check that the front sight attachment screw is tight and the sight element held within is secure. Check the rear sight for play and tightness on the breech block.
SCOPE MOUNTS
Any old scope mount just won't do on an Air-gun, you must use a scope mount specifically designed for Air-gun use. These may have an integral scope stop pin that locates in special arrestor holes milled into the receivers of the best Springers. Spring piston Air-guns don't just recoil backwards, they snap forward too and coupled with the vibration of the mainspring will continually drive a less than proper mount off the scope grooves. Separate scope stops are also available for the same purpose. Scopes can also move through the scope rings but this problem is usually eliminated using the right scope mount.
USING A REGULAR FIREARM SCOPE
If you are serious about your Air gunning and want the best performance out of your Air-gun, you must use a scope specifically designed for Air-gun use. Today's magnum spring piston Air-guns will promptly break a less than proper Air-gun scope. As mentioned previously, Air-guns recoil backwards then snap forward; this is what destroys regular scopes.
Proper Air-gun scopes have their lenses and reticule braced at the front and the back whereas most regular firearm scopes are only braced at the rear. This double recoil peculiar to Air-guns, coupled with the vibration of the mainspring, will quickly destroy even the biggest brand names in scopes.
Secondly, Air-guns shoot at shorter distances than regular firearms, and finally most regular firearm scopes are parallax corrected to 50 yards or more.
Proper Air-gun scopes have an externally adjustable parallax ring on the objective or front end to focus clearly at all distances down to about 10 meters. This can also be used as a range finder to estimate distances to your target. Finally, Air-guns have a much more pronounced trajectory than firearms and proper Air-gun scopes have an elevation bias so there is more up than down adjustment, eliminating the need to shim the scope mount and possibly crush or bend the scope tube.
INCORRECT BARREL TENSION
Barrel cocking Air-guns must have the pivot tension set carefully. Too much and the barrel detent will not consistently lock up and there will be galling of the breech block. Too little and there will be blow by at the breech. Both situations will cause wild and erratic groups. The correct tension is the point where the barrel will just stay anywhere on the return arc after cocking. Better barrel cocking Air-guns have adjustable pivot tension.
You must use proper gunsmith screwdrivers, keep your fingers out of the trigger guard and don't adjust a cocked gun! Loosen the right hand side screw/nut and tighten the left hand side bolt. When the tension is correct, tighten the nut against the bolt and recheck.
THE WRONG PELLET
Most inaccuracy queries emanate from owners of .177 magnum Sporters capable of muzzle velocities in excess of 1000 fps. In the power race, many manufacturers use the very lightest pellet available to achieve their advertised velocity and boost their sales. Invariably, this pellet is not the best for these guns, in terms of accuracy, energy and velocity retention downrange where it counts. Every gun is different and what works for one gun doesn't mean it will work on the next gun even if it is the same make and model.
Buy an assortment pack in your caliber, and see which pellets shoot the best group at your preferred shooting distance. Pellet induced accuracy problems on lower powered Air-guns can usually be cured by switching brands or types. Don't use old and oxidized pellets or any deformed examples - discard them immediately. Only use high quality lead pellets from respected manufacturers. Cheap pellets are false economy.
DIRTY BORE
Air-guns do foul barrels but not in the same manner as regular firearms. Instead minute traces of lead and the gun's mechanisms spray lubricants from the compression chamber that deposit in the rifling. This must be carefully removed with a proper Air-gun barrel cleaning kit.
It’s strongly recommended to use a good Clean Kit which is a compact flexible rod that won't damage the delicate crown or rifling and it covers all four calibers. Carefully follow the directions for the best results.
Don't use regular firearm solvents because they will attack the seals. Use a gentle degreaser using 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 1000 shots or so. On any Air-gun with greater than match velocity, use multiple Quick Clean pellets.
Always sight in your Air-gun each time you open a new tin of pellets. Variations can occur between batches.
INCORRECT SHOOTING TECHNIQUES
Regular firearm rules doesn't work on spring piston Air-guns. That is why many expert firearm marksmen can't shoot Air-guns accurately and why many expert Air-gunners shoot regular firearms so well. There are two basic reasons:
1.Hold your Air-gun loosely against your shoulder and let it jump around when you fire it. Don't pull it in hard into your shoulder or strangle its forearm and don't rest the forearm on a hard surface. Let it recoil and vibrate freely - don't try to prevent it.
2.When you sense that your Air-gun has fired, the pellet is only just starting up the barrel. The lock time is so much slower on Air-guns compared to firearms so you have to adjust and follow through. Hang onto your sight picture just a little longer and your groups will shrink. Naturally, trigger, breathing and stance principles still apply and there are plenty of books available on these topics to consult. If you have followed all these suggestions and still have accuracy problems your Air-gun may need the attention of an air-gunsmith. From experience it is far cheaper in the end to have an Air-gun specialist attend to it.
HAPPY SHOOTING
Brihacharan
Here's some 'GYAN' I wish to share - especially for those who are getting initiated into Airgunning as a sport.
www.air-rifle.net/inaccuracy/inaccuracy.html
Air Gunners frequently complain that "I can't hit the broad side of a barn." Invariably, the frustrated owner has "tried everything, but it still won't give a decent group no matter what!"
Unfortunately, the information supplied with most new Air-guns is fairly ordinary at best and won't offer much assistance, so here is a list of the frequent problem areas to look at before you give up in despair. Most of this information applies to conventional spring piston Air-guns.
LOOSE STOCK SCREWS
This is probably the most common cause of inaccuracy in Air-guns. Even a quarter turn loose can translate to 50mm difference at 25 meters. Most Air-guns have three blade or Phillips head screws securing the action to the stock - two in the forearm and one through the trigger guard. These must be firmly tight at all times with lock washers in place. Loose screws on the breech-block assembly will also affect accuracy on break-barrel models.
CAUTION!
Before you run to your tool box – Air-gun slotted screws, are different. They require special screwdrivers with parallel tapers unlike carpentry screws. Use a regular screwdriver and you risk damaging the screw head, the gun and yourself-sometimes irreparably! We offer the handy and compact Gunsmith Screwdriver Kit that covers most of the screws you will encounter on your Air-guns including Phillips heads. Don't over tighten! Any more tension than firm will probably compress the wood and destroy the stock, particularly in the forearm.
LOOSE SIGHTS
Open Sights - check that the front sight attachment screw is tight and the sight element held within is secure. Check the rear sight for play and tightness on the breech block.
SCOPE MOUNTS
Any old scope mount just won't do on an Air-gun, you must use a scope mount specifically designed for Air-gun use. These may have an integral scope stop pin that locates in special arrestor holes milled into the receivers of the best Springers. Spring piston Air-guns don't just recoil backwards, they snap forward too and coupled with the vibration of the mainspring will continually drive a less than proper mount off the scope grooves. Separate scope stops are also available for the same purpose. Scopes can also move through the scope rings but this problem is usually eliminated using the right scope mount.
USING A REGULAR FIREARM SCOPE
If you are serious about your Air gunning and want the best performance out of your Air-gun, you must use a scope specifically designed for Air-gun use. Today's magnum spring piston Air-guns will promptly break a less than proper Air-gun scope. As mentioned previously, Air-guns recoil backwards then snap forward; this is what destroys regular scopes.
Proper Air-gun scopes have their lenses and reticule braced at the front and the back whereas most regular firearm scopes are only braced at the rear. This double recoil peculiar to Air-guns, coupled with the vibration of the mainspring, will quickly destroy even the biggest brand names in scopes.
Secondly, Air-guns shoot at shorter distances than regular firearms, and finally most regular firearm scopes are parallax corrected to 50 yards or more.
Proper Air-gun scopes have an externally adjustable parallax ring on the objective or front end to focus clearly at all distances down to about 10 meters. This can also be used as a range finder to estimate distances to your target. Finally, Air-guns have a much more pronounced trajectory than firearms and proper Air-gun scopes have an elevation bias so there is more up than down adjustment, eliminating the need to shim the scope mount and possibly crush or bend the scope tube.
INCORRECT BARREL TENSION
Barrel cocking Air-guns must have the pivot tension set carefully. Too much and the barrel detent will not consistently lock up and there will be galling of the breech block. Too little and there will be blow by at the breech. Both situations will cause wild and erratic groups. The correct tension is the point where the barrel will just stay anywhere on the return arc after cocking. Better barrel cocking Air-guns have adjustable pivot tension.
You must use proper gunsmith screwdrivers, keep your fingers out of the trigger guard and don't adjust a cocked gun! Loosen the right hand side screw/nut and tighten the left hand side bolt. When the tension is correct, tighten the nut against the bolt and recheck.
THE WRONG PELLET
Most inaccuracy queries emanate from owners of .177 magnum Sporters capable of muzzle velocities in excess of 1000 fps. In the power race, many manufacturers use the very lightest pellet available to achieve their advertised velocity and boost their sales. Invariably, this pellet is not the best for these guns, in terms of accuracy, energy and velocity retention downrange where it counts. Every gun is different and what works for one gun doesn't mean it will work on the next gun even if it is the same make and model.
Buy an assortment pack in your caliber, and see which pellets shoot the best group at your preferred shooting distance. Pellet induced accuracy problems on lower powered Air-guns can usually be cured by switching brands or types. Don't use old and oxidized pellets or any deformed examples - discard them immediately. Only use high quality lead pellets from respected manufacturers. Cheap pellets are false economy.
DIRTY BORE
Air-guns do foul barrels but not in the same manner as regular firearms. Instead minute traces of lead and the gun's mechanisms spray lubricants from the compression chamber that deposit in the rifling. This must be carefully removed with a proper Air-gun barrel cleaning kit.
It’s strongly recommended to use a good Clean Kit which is a compact flexible rod that won't damage the delicate crown or rifling and it covers all four calibers. Carefully follow the directions for the best results.
Don't use regular firearm solvents because they will attack the seals. Use a gentle degreaser using 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 1000 shots or so. On any Air-gun with greater than match velocity, use multiple Quick Clean pellets.
Always sight in your Air-gun each time you open a new tin of pellets. Variations can occur between batches.
INCORRECT SHOOTING TECHNIQUES
Regular firearm rules doesn't work on spring piston Air-guns. That is why many expert firearm marksmen can't shoot Air-guns accurately and why many expert Air-gunners shoot regular firearms so well. There are two basic reasons:
1.Hold your Air-gun loosely against your shoulder and let it jump around when you fire it. Don't pull it in hard into your shoulder or strangle its forearm and don't rest the forearm on a hard surface. Let it recoil and vibrate freely - don't try to prevent it.
2.When you sense that your Air-gun has fired, the pellet is only just starting up the barrel. The lock time is so much slower on Air-guns compared to firearms so you have to adjust and follow through. Hang onto your sight picture just a little longer and your groups will shrink. Naturally, trigger, breathing and stance principles still apply and there are plenty of books available on these topics to consult. If you have followed all these suggestions and still have accuracy problems your Air-gun may need the attention of an air-gunsmith. From experience it is far cheaper in the end to have an Air-gun specialist attend to it.
HAPPY SHOOTING
Brihacharan
). Jim Corbett shot with both eyes open. With a telesight it might be a problem as the focus of both eyes will differ. I personally get a double image on keeping both eyes open, but probably that might go away with practice. Also, I wear glasses of high negative power, which will impact the sight picture differently.