I'm often asked, "Why should I get my gun tuned?"  There are several reasons you might want to get your gun tuned.  In this article I'm going to list them as an education page so you can ask more informed questions when asking "what is done in a tune?" or "What will it do for me?"  Often I'm asked what is a tune, only to describe something the listener is totally unfamiliar with, or can't picture at all.  It's kind of a moot point?  Rest assured, if it's reservations about the amount of money spent for the work done, most  aren't charging enough.  R&D time, lathes, milling machines, material stock, tooling, stock working equip. and the like, coupled with the amount of time machining and fitting parts to your gun, most are on the losing end.
 
 

Paul Watts
 

Just about every gun on the market has some weak links that could stand some improvement.  Some gun makers use good quality springs.  Notably, AirArms and Webley.  Some others use oil hardened music wire.  They do this because "power hungry americans" want cheap power. Besides, in their opinion, how many people will even shoot their gun 2000 rnds. These springs stressed to the max so as to give lots of power and fairly low cocking effort.  Small diameter spring wire treated this way has a fairly short life span in a spring gun.  Especially, in guns that tend to diesel.  A good bit of people feel that springers are only designed to operate at 12ftlbs or they wont last.  I believe the afore mentioned spring problem is why so many, early on in airgunning, held to this position.  I don't buy it.  When I tune a gun I can often get 70-80fps more than a factory gun that was already hot and in so doing make the gun last 10-50 times longer than even the same guns 12ftlb counterpart.  The springs I'm installing will outlast the factory springs and give improved performance.  But the performance aspect will be covered later.

In some guns there are contact points that can gall due to high loads and lack of lube.  Often, points like this can be re-machined or fitted with thrust bearings or buttons that will just about eliminate the problem.  The end plug on an R1 or HW50 etc.. are a good example.  So are the sides of the breech on HW (Beeman) barrel cocking guns.  I offer brass or delrin inserts with custom machining to eliminate this problem.  On AirArms guns I use synthetic spacers in the rear of the spring to eliminate this problem on them.  I do the same on HW guns.  On many guns the piston or compression tube can have flat bottomed holes machined into them to install buttons as well.  Buttons are usually 1/4 inch round delrin, inserted into the holes but protruding to take up any slack between the part and the receiver while also reducing the chance of any galling from unhardened or poorly hardened parts.

Proper lubrication is a key element in a gun lasting longer too.  Too much lube in the compression chamber or the wrong kind will burn seals, or cause dieseling that will shorten the life of the spring.  A spring that is lubed with too much "heavy" grease will have wide velocity changes from cold to hot weather.  You'll also be able to notice impact point changes from just the first few shots, until the gun settles in (low velocity starting out).  This can also be seen in a new tune but will subside after break in (higher velocity starting out).  Of course not enough lube or the wrong kind can cause galling or accelerated wear in your gun as well.

A tune can effect several areas of performance and not every gun is the same in responding.

POWER: Some guns respond well to bringing the power down but other guns have lots of potential for increased power while keeping the gun very shootable or pleasant to fire.  If a gun doesn't respond well to jacking the power up, I'm not going to do it for you, no matter how bad you want it.  I just don't want my name associated with that kind of work.  Some guns do respond well to power increases and I'm more than happy to do it.  The power I tune for, will also be determined by the caliber of the gun and the weight or particular pellet being used.  Generally, the larger the caliber, the smoother the gun will shoot and can thus be powered up (sometimes!).  I don't recommend high power R1's in 177cal for example.  In 22cal with the same tune you'll get more power, less recoil and less noise.

RECOIL:  recoil can be reduced buy either using a weaker spring or by speeding the two way movement of recoil, up to where it is not as noticeable.  Sometimes you can get more power and less recoil. But you always want recoil to be controllable, or straight back if you can. It depends on the design of the gun more than anything else. Some guns will not shoot smoothly no matter what you do.  Oversized transfer ports, inside diameter of the barrel being oversized, or too loose a pellet fit can cause this problem as well.  Sometimes a gun with this last problem can't be tuned smoothly until the owner is willing to opt for a new barrel.  Some HW guns are tight in the breech and open up only to have the choke slow the pellet down before exiting the barrel.  Chopping a barrel off on one of these guns will give you a vibrating heavy recoiling mess.  Some guns that have shortened barrels shoot fine.  This is something I heavily recommend that someone not do at home.  Have a respectable smith who can re-choke the barrel do it, someone who will also stand behing his work.

VIBRATION:  TWAAAAANNGGGG! The noise the spring makes after the gun has fired.  This is not recoil as some keep alluding to.  It's the noise and buzz you feel after the gun has fired.  It is about 60-70% of the noise a spring gun makes.  Getting rid of or reducing this will reap you several benefits.  A quiet gun will often allow a follow up shot in some hunting situations.  Also, it'll make the gun less noticeable if you want to plink around the house without bothering the neighbors.  On long barreled, barrel cocking guns, I've noticed that a reduction or elimination of vibration will give a noticeable improvement in accuracy.  Carbine barrels are more rigid and tend to benefit less from this.  The biggest improvement in reducing vibration is that your stock screws tend to stay put.  If your stock is soft, wood can compress under the head of the screw due to recoil but most often I've found that reducing vibration with properly machined guides (not lube) with a drop of 242 loctite will just about solve this problem.  Besides, that smooth solid THUNK the gun makes without vibration just makes it feel better. EEEWW, IT'S CUSTOM!

ACCURACY:  Bottom line, less recoil that is straight back and tighter velocity spreads will give better accuracy.  15-20fps speed is acceptable and won't affect accuracy much.  Most of the guns I've tuned will get about a 3-10fps spread.  The exceptions are guns with loose fitting pellets due to oversized bores, inconsistent pellets or tap loading guns.  Tap loading guns are notorious for wide velocity spreads.  I for that reason tend to not want to do any work on them for accuracy problems.  They also tend to leak air and get low velocity.  Either by the tap being loose, or the bore being oversized, and the pellet's fit lets air bleed by.

SMOOTHNESS:  I have always tended to think smooth meant little to no noise when cocking, no vibration and muted recoil.  Like riding in a new car.  No squeaks rattles and everything goes snickt when you open or close it.  It's a quality that has to be appreciated in person and isn't easy to describe.

Putting tuned on an ad will not likely add much to the value of the gun.  There, I said it.  Putting a name on it like "Tuned By -----" will help some but it's often not a big selling point.

That said, it does help a lot if you're displaying a gun at a show or in person.  If the person has any experience with the model of gun, he will immediately notice the quality difference.  I've had people try guns they had no interest in buying, then buy the gun because it shot soooo sweet.  It is a big selling point if the person gets to shoot the gun!!  No doubt about it. If they do shoot it you can usually recover the price of the tune in the selling price, but often the person buying doesn't even know what a tune is.  It isn't helped by the fact that people are opening up guns, dumping lube in them and calling them "tuned."  Get a reputable smith to do the tune and the value will be there later on.

The gun is disassembled and cleaned out.  Parts from your gun are machined and polished to accept new parts, or just smoothed out for some of the above reasons.  A new spring is selected for your gun depending on desired power depending on caliber and pellet to be used or the general use of the gun (i.e.. hunting or plinking or target).  Spring guides are made from steel or the finest synthetics depending on where it's going to be used.  They are fitted to the individual spring to be used to eliminate vibration and control recoil characteristics.  A better designed seal is sometimes used.  Sometimes to increase power.  Sometimes it's to smooth the firing cycle or last longer.  On some guns the factory seal is about optimum but the seal is always replaced with a new one.  Yours should never be reinstalled in your gun unless the gun is brand new.  The gun is reassembled using from three to five different lubes depending on the type of materials the guides are made from, for spring lube.  One type of moly is used for pressure points, while another is used for the compression chamber and piston seal.  Another lube is used on the receiver walls where the compression tube or piston slides.  The trigger is lubed with special oils, if it is reworked, as well.   All this takes a good bit of time to do right.  For the effort put into it, the money isn't very much.

I hope some of this helps explain some things you didn't understand before.  This is about what everyone that emails me, wants me to write.  I've been working on this for about three hours this morning.  Trying to remember everything (which I probably didn't.)  I just don't have the free time to answer everyone in this much detail.  I hope this will help.
 

^{Paul Watts}