[jwongie]

The Inspiration
Okay so there is always lots and lots of questions in the pump forum about springing, valves, pump stroke, trigger pull, sound signature(farting/venting), and just overall sniper tuning. This article will be my best attempt at giving everyone the information to maximize the potential of their sniper.

Before going any further please know how to:
-Polish stainless steel parts(countless guides are available in the voided warranty section)
-Disassemble Autocockers/Snipers

Valve Talk
This is completely my opinion but i firmly believe that the valve you use is one of the least dependent factors when tuning a sniper. Things that will play a huge part in tuning a sniper a springs and hpr pressure. Stock Wgp valves work just fine.(may edit pending testing a few more valves)

Springs
When questions about springs are asked in the "pump forum" many people tend to just reply with "just get a maddman spring kit". These springs are much too hard for our application. The springs that you should look for are much lighter. How light? Your main spring should be comparable to a ccm main spring, thats probably the best measure i can give you. If in doubt just get a ccm spring. As for valve springs, I have found that ccm valve springs are a little too hard for me. Valve springs that i look for are slightly longer and slightly softer(sear springs are great for this). Your valve spring should be just heavy enough to close your valve and nothing else(this will alow you to use reg pressure to affect hammer bounce/venting more effectively). A good way to test your valve spring is to install it with your valve in your body. With your hammer in the lower tube and only your hammer, your valve spring should not compress at all. Once you start to screw in your ivg and main spring in your valve spring should start to compress. If you have found a valve spring that behaves this way you are ready to begin polishing.

Polishing
The first step in attaining a smooth pump stroke and trigger pull is to polish all internal parts that create friction.
Parts that create friction and that MUST be polished consist of:
Valve stem
Polishing this will allow you to squeeze out more fps, reduce hpr pressure, and reduce spring tension. (Lighter pump stroke,Quieter sound signature)
Hammer
Polishing this will allow you to squeeze out more fps allowing you to reduce spring tension. (Lighter/Smoother pump stroke)
Hammer Lug
Polishing this will reduce friction and wear on sear and lug. (Lighter/shorter trigger pull)
Sear
Polishing where your sear contacts the lug and trigger will reduce friction and wear on lug and sear. (Lighter/shorter trigger pull)
Main Guide Rod/Secondary Rod(If applicable)
Polishing this will reduce friction with rods and pump handle.(Smoother Pump Stroke)

Once you have polished all of these parts you are ready to reassemble your marker. Upon reassembly you should notice a major difference in pump stroke and trigger action, if not, break down your marker and continue to polish.

Reg Pressure and Farting/Venting

Farting/Venting: The WHY!
Before we get to the how to, first we will go over the why. Farting and venting is caused by an imbalance in the relation between the force opening your valve and the force closing your valve.

In a well tuned sniper once the sear drops the main spring will propel the hammer into the valve stem, opening the valve, releasing air up through your bolt and your valve spring and reg pressure will close your valve.

In a sniper that farts, too much or little main spring tension, too much hpr pressure, or too much valve spring tension will cause the hammer to bounce, this in turn reopens the valve repeatedly until your hammer is at rest.

In a sniper that vents, too much or little main spring tension, too little hpr pressure, or too little valve spring tension will not close the valve quit enough, thus producing a dwell that is too long and in turn releases more air then needed to propel a paintball.

The Identification and "The Fix"
Farting can be identified by . . . . well a sound that replicates a fart, to fix farting you must decrease your reg pressure to reduce the hammer bouncing on the valve stem or reducing main spring tension which reduces the force hitting the stem which can also eliminate hammer bounce and farting.

Venting can be identified by a hiss following each shot but can be as extreme as the valve not being able to seal after each shot unless your marker is pumped, the middle of this spectrum is a low pitched farting sound, more along the lines of a burp, opposed to the high pitched fart of hammer bounce. To fix venting you need to reduce mainspring tension allowing the valve to close quicker or increasing reg pressure also closing your valve quicker and shortening your dwell.

Reg Pressure
Sweetspotting, i will not go into a long rant about why you shouldnt sweetspot the reg on your SNIPER. Ill keep it short and sweet. Sweetspotting will not eliminate farting or venting.

Tuning

For this next section you will need:
-Air
-Bag of paint
-Chrono

Now with your marker assembled turn you reg all the way down and back your ivg flush. Cock your marker, turn your reg up and shoot without paint, turn your reg up and shoot. Your valve probably will not seal after your first couple shots but eventually as you follow this procedure your marker will vent, then start to fart. At this point you will start to shoot paint. Shooting paint will make the difference between farting venting and a good shot more audible. in very small increments, turn down your reg pressure and shoot until farting is not audible. What should it sound like? It should sound like a shot from a mech cocker or very similar. Once you have achieved this sound shoot some paint over the chrono, in most cases your velocity will be low. Now, turn in your ivg in small increments, adjust your reg pressure accordingly, fire over chrono, and continue to follow this procedure until your velocity is where you want it to be.

Congratulations! you now should have a sniper that shoots and feels comparable to the best pumps currently being manufactured if not much much better.

[scroadkill]

Well written piece - but.. IMO tuning a sniper is about either minimizing the main spring for the lightest pump stroke possible -or- maximizing reliability. ^ this article suggests the way to tune a sniper is to tune it for lightest main spring - which puts a great deal of dependency on all other things being in perfect balance at all times or the system will go out of whack.

IMO a medium main spring will allow for a heavier valve spring which will allow for a slightly higher operating pressure which (given a fixed volume) will allow for more reliable operations to close open and close the valve w/o bouncing... and more reliable operations. Of course this comes at the cost of a slighter harder pump stroke. So it really depends on which aspect you want to emphasize. Blue for the win.

[jwongie]

Y not have a light pump stroke, no farting, and nice crisp quiet shot?

[scroadkill]

I'm not sure there is is an audible difference between 300psi and 350psi and I haven't met that may people able to get a stock pre2K valve chamber down below 300psi and stable. Granted the old sniper1/sheridan springs are a beast in comparison I find blue vs ccm mains to not worth the effort or additional problems.

[jwongie]

2k+ body can run lower then 300 with fairly little trouble

[scroadkill]

fair enough - it just seems like most of the guys I know who did changed their mind shortly after proclaiming 325-375 to be more stable.

[jwongie]

It really truly depends. Reg consistency helps. Polishing also improves reliability at lower pressures.

[drgonzo]

I actually think valves can be very important, or rather the right valve can make things a lot easier. Thing is, most valves are of the type that don't make things easier. Off the top I can only think of 2 or 3 valves that make things easier.

[jwongie]

Originally Posted by drgonzo

I actually think valves can be very important, or rather the right valve can make things a lot easier. Thing is, most valves are of the type that don't make things easier. Off the top I can only think of 2 or 3 valves that make things easier.

share these valves with me please

i think my best guess would be palmers?? havent tried that one yet

[drgonzo]

Originally Posted by jwongie

share these valves with me please

i think my best would be palmers?? havent tried that one yet

Palmers, CCM, old stock.

Oh and mQ

[Heaton]

Jwongie, can you clear your PM box, please? Thanks!

[jwongie]

Originally Posted by drgonzo

Palmers, CCM, old stock.

Oh and mQ

oh yea, how could i forget about the mq. . . i dont think my mq project will ever get done.

[jwongie]

Originally Posted by Heaton

Jwongie, can you clear your PM box, please? Thanks!

cleared, sorry!

[xROMAKx]

very useful thread. lots of good info on tuning. thanks!

[OnePumpChump316]

Great post!

[pump]

Originally Posted by jwongie

In a sniper that farts...little main spring tension,

In a sniper that vents...little main spring tension

i think you are incorrect