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Discussion Starter · #1 · (Edited)
Need for Speed? The FPS Checklist!

FPS on the mind? This is a reference for all of those who feel like their BASR (Bolt-action Sniper Rifle) is missing FPS or for those who simply want more BANG out of their sniping machine.


Table of Contents


A. Accessories
B. BB's
C. Bucking
D. Chronograph
E. Cylinder
F. Cylinder head
G. Hop-up Chamber + Adjustment
H. Inner barrel (spacers included)
I. Nub
J. Piston body
K. Piston head/o-ring
L. Spring
M. Spring guide
N. Spring guide stopper
O. Stock Body

A. Accessories

1. Flash hiders/ mock suppressors/ barrel extensions

  • Sometimes these muzzle accessories are not properly aligned or poorly made and FPS can be lowered without the user knowing. I find it very important to chronograph a rifle with and without the accessory.
  • If the FPS is decreased with an accessory attached by ~5-10FPS or more, then the accessory is altering the BB's flight in some way.
2. Proper Alignment

  • Make sure that all available threading is secured properly and the inner barrel is aligned straight so the accessory does not touch the BB.

B. BB's


1. Washing/Cleaning
  • http://www.airsoftsniperforum.com/showthread.php?t=1040 <- This entire thread discusses techniques and experiences with washing BB's. This method does not improve FPS dramatically, but it evens out and cleans the surface of certain BB's for more consistent and slightly better FPS/accuracy.
2. BB brand quality

  • Certain brands are known for having bad BB polish, uneven internal bubbles, varying weight, and varying sizes. All of these components are important for consistent FPS as well as creating higher or lower FPS readings in a chronograph. Sometimes bad quality BB's will create low FPS readings as mentioned in the next point.
3. For chronograph readings

  • Using a different brand of 0.20g BB's will alter your FPS reading for better or for worse. If you suspect your rifle is shooting lower than expected, try a different brand of high quality BB's. I have noticed as much as a 20FPS difference just from switching to a different BB brand.
C. Bucking


1. Thorough Cleaning


2. Simple Cleaning

  • A dirty bucking can ruin your FPS consistency, FPS output, and accuracy. For a simple clean, remove the bucking from the barrel and wash it with soap and warm water (inside & out) until you believe it is fully cleansed. Allow the wet bucking to air dry and re-install. You can apply grease on the outside of the bucking to assist the installation of any nubs (i.e. PSC/SCS nub.) Avoid any grease/lube/oil from contacting the inside of a bucking. It causes the BB to slip and contact the bucking in unpredictable ways which will cause inconsistent FPS.
3. Proper Installation

  • Make sure that the bucking is properly aligned with your inner barrel so the bucking maintains a proper seal. Some people install the bucking improperly and experience a lower FPS reading because of air loss.
4. Type of Bucking

  • Hard buckings and soft buckings effect FPS depending on the expected FPS output. Harder buckings are recommended for higher FPS setups.
5. Brand of Bucking

  • Certain brands work better than others when sealing for compression. Nine-ball, Prometheus, Firefly, Systema, TM, and PDI are all known to have great air sealing reputations.
6. ABB Rings

  • These rings were specifically made for VSR/Bar-10 rifles by a user named Noobie. Until I can gain more information regarding where to purchase these rings, I will leave this section incomplete for the moment.

7. Dental Floss Mod

  • This mod apparently works just as well as ABB rings, but the biggest downside is the potential of damaging your bucking if tightened too much or if very thin floss is used. This link will demonstrate installation:
10. Damaged Bucking

  • A damaged bucking will almost always decrease FPS. If there are holes or tears in your bucking then it's time to replace it. These holes and tears will not only effect your FPS output, but also your FPS consistency and accuracy.

D. Chronograph

1. Chronograph Brand

  • Xcortech is a highly recommended chronograph because it gives the closest approximation to a BB's REAL FPS.
  • Madbull is known to have an average deviation of +/-30 FPS and sometimes as much as 100FPS in several occurences.
  • If you believe your FPS is lower than expected and you've done all that you could with internal parts, try a different chronograph and re-test your FPS. I've personally experienced a difference of 35 FPS when going from a Madbull to an Xcortech.
2. Aiming consistency/angle

  • When chronoing, make sure to aim exactly the same for each shot. The sensors on most chronographs capture speeds differently when the BB is traveling at different angles. Consistent aiming will ensure proper readings.
3. Distance when chronoing

  • The distance of the muzzle to the chronograph's sensors can effect FPS readings. I usually remove the muzzle adapter for chronographs that include this option. You must be more careful when aiming through the chronograph opening, but this will allow more accurate FPS readings.
4. Vibration

  • Make sure to not contact the chronograph or vibrate the chronograph in any way, otherwise FPS readings may show much lower readings than expected.

5. BB brand

  • Please refer to section #3 of BB's
6. Battery Life

  • Low battery life sometimes affects FPS readings. Some people claim to get high readings while others get low readings. Just make sure the chronograph being used is properly charged.

E. Cylinder


1. Cleaning

  • Too much dirt, grease, or oil can effect FPS. Use soap and water and/or rubbing alcohol to clean all the dirt/grease inside the cylinder. Allow to air-dry or use lint-free cloth.
2. Re-greasing

3. Teflon and other coated Cylinders

  • These cylinders allow for smoother bolt operation (push+pull), but they do not necessarily increase FPS like one would expect. In fact from my experience, the FPS readings from a non-coated cylinder is the same as a coated one.
4. Bore-up Cylinder for VSR/Bar-10 platforms

  • There are bore-up cylinders available for these platforms which increase the cylinder volume. The volume increase is not tremendously larger, but they can increase FPS just enough to make a difference.

F. Cylinder head



1. Taper/bevel mod

2. Teflon tape mod

3. Nozzle polishing mod

  • This modification may increase FPS by 10-30 FPS. This involves applying at least 2 coats of clear nail polish (or any hard + chip resistance substance) onto the cylinder head nozzle. This allows for better air seal between the cylinder head nozzle and the bucking lips. This picture I rendered should give a better idea:

4. Nozzle boring mod

  • It is possible to bore out (increase the inner diameter) of the cylinder head's nozzle a little more. This will enlarge the passage that air can flow through which enables more air to accelerate the BB.
  • Please note: It is possible to permanently ruin your cylinder head so perform this mod at your own discretion.
  • To bore out the nozzle, you can use a rotating tool of some sort (drill, dremel, etc.) and carefully sand the inside of the nozzle until you are content with the diameter increase.
  • Boring out the nozzle does indeed increase FPS, by a fair amount if your not shy with the drill size..... combine this with a deep ported and polished cylinder head and you can gain around 60 fps if done right and you get the port shape right. -Vindicareassassin
5. O-ring replacement


  • If your o-ring is severely damaged then simply find an o-ring replacement at your nearest hardware store. Although requiring a cylinder o-ring replacement is not too common, finding a replacement is at the utmost importance.

G. Hop-up Chamber + Adjustment



1. O-ring replacement for PDI Chambers

  • The o-rings for the PDI hop up chambers were designed for a better air seal. They act similar to teflon taping both ends of the bucking to your inner barrel. If you are suspecting FPS loss somewhere and all else fails, you may need to change your o-rings.
2. Adjusting hop-up level for FPS

  • It's commonly known that adjusting the hop up too high or too low can effect FPS dramatically. Adjusting to find your maximum FPS can be tedious depending on your hop up chamber, but this is necessary to determine the maximum output on the current spring installed.
3. Upgraded hop-Up chambers

  • In particular, PDI hop up chambers include air seal o-rings for better compression and this chamber also allows the use of AEG barrels and AEG buckings- all of which can potentially increase FPS significantly.
4. TDC Mod

  • This modification is primarily for VSR/Bar-10 platforms. TDC, or Top-Dead-Center, virtually removes all hop-up arm foul play. Adjustments will become more consistent and therefore FPS will become more consistent. If you feel that your hop-up arm may be causing FPS inconsistencies or accuracy issues contact username: Cheeseman ... He can answer your questions and has the capability of installing a TDC Mod.

5. Aps2/Type96 PDI Hop-up Chamber Booster Spring

  • The booster spring included with the hop-up chamber is designated to perform the same way as the O-ring which goes around the lever arms. The booster spring prevents the lever arms from jumping up when a BB passes from inside the inner barrel. This keeps the lever arms consistently in place and therefore increases FPS consistency.
  • The spring is not required, but if you need more consistent hop up or more consistent FPS, I would recommend it.

H. Inner barrel (spacers included)


1. Cleaning

  • A dirty barrel can undoubtedly decrease your FPS output so keeping it clean is required from time to time.

  • Rubbing alcohol and a lint-free cloth (or some people use teflon tape) is all you really need to clean the barrel. Run a few cloths saturated with rubbing alcohol a few times down the barrel from bucking end to muzzle end with the bucking taken off. Once there is no more dirt residue on the cloths, run a couple of dry cloths until you are satisfied.
2. Polishing

3. Barrel Spacers

  • Barrel spacers will reduce vibration of the inner barrel and this has been proven to increase FPS slightly for various people (myself included)
  • Electrical/Duct Tape Spacer: Simply wrap several rounds of tape in at least 3 places on the inner barrel. The more spacers, the better. When placing the inner barrel back into the outer barrel, it should be a very snug fit to eliminate vibration.
  • One-piece Paper Spacer: http://www.airsoftretreat.com/forums/index.php?topic=82742.0
  • Wax Barrel Spacer:
Please feel free to leave suggestions or criticize any part of this post.
This thread is intended to be updated so this is not the final version.

It's quite late where I'm located and I'm going to knock out soon. I will probably revise and/or add more sections or information at a later time.
:zzz:
 

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Discussion Starter · #5 ·
I have written a guide on how to properly care for and clean our bucking, I noticed your cleaning section was a bit lackluster. ;)
I completely agree on it being lacklaster so I edited it just a bit >:D

The section above Simple Cleaning titled Maintenance had your link describing how to thoroughly clean the bucking. Maintenance is now renamed Thorough Cleaning.

And thank you everyone :shot:
 

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Lovely. I like the guide, major props. I disagree with the statement that our springs lose more power than an AEG spring, they go through 10k cycles in 3-4 days (or more) of airsofting, I have rifles that haven't seen 10k cycles yet. Even though it is left cocked for most of a game, an AEG spring is about the same, and our springs are stronger and beefier than theirs anyway.
 

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Discussion Starter · #7 ·
Lovely. I like the guide, major props. I disagree with the statement that our springs lose more power than an AEG spring, they go through 10k cycles in 3-4 days (or more) of airsofting, I have rifles that haven't seen 10k cycles yet. Even though it is left cocked for most of a game, an AEG spring is about the same, and our springs are stronger and beefier than theirs anyway.
I will edit that section because I understand your logic. I suppose there might be other variables at work because my springs tend to lose power perhaps quicker than most, but I have a feeling it has to do with how much testing I perform >:D
 

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Amazing guide! Printed and added to my folder of useful airsoft maintenance prints for maintaining my rifle. ;) Definitely should be stickied!
 

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A good guide well done me thinks, very informative to the FNG :yup:

Just to clear up a few things......

Boring out the nozzle does indeed increase FPS, by a fair amount if your not shy with the drill size..... combine this with a deep ported and polished cylinder head and you can gain around 60 fps if done right and you get the port shape right.

Far more effective, but more effort required, is the rubber O ring set into a home ground groove at the point wher the nozzle finishes going into the hop rubber, so that the O ring presses against the rubber, this seals the nozzle/rubber joint far more effectively. I would still do the nozzle/polish shimming though as this helps to guide the nozzle into the hop unit at a nice straight angle.

Dont be fooled by a short barrel vs fps, you can get almost as much fps from a short barrel as you can from a long, PROVIDED that, and this is the most important thing, the cylinder a barrel volume are matched, you should be aiming for a ratio of between 1.7 & 2.4 cylinder volume over ANY barrel length, lower volume suits lighter ammo, higher volume suits heavy.

Obviously, this is all relative as should you fit a longer barrel your fps will undowtedly go up, but if you prefer to use a scout length rifle, as I have been known to do upon occassion, then feel comfty in the knowledge you to can still use the big number fps' you just have to put a little more effort into extracting it.

Barrel length is not as important as everyone seems to make out and if you are running an 800mm barrel you need a slap, and if your using anything over 510mm you need a kick in the arse, these lengths are pointless and only gain you fps over any kind of accuracy you could be using more constructivley. Longer and tighter are most definately NOT better!!

Yes, yes, there are now going to be loads of pillocks come on here and claim their 1000mm x 5.97mm barrel will give a 2" group @ 500 yards and I will call :bs: , 10 years practical airsoft gungineering experience tells me so, unless its been built specificaly to sit in a vice and shoot at paper.

Lastly theres no mention of LRBs, I know alot of ordinary folks out there don't know of or understand them, or how to go about installing them, but there still worth a mention as they are highly effective for minimal out lay, I'm sure myself or cheeseman can help with any relavent questions ( there's also a thread I wrote about them in the AEG section ), and to save you all looking.... http://www.airsoftsniperforum.com/showthread.php?t=2946

Rants, pointers and pokes in the right direction over...

Peace...

Carry on! :shot:
 

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Discussion Starter · #11 ·
Vindicare, I would like to ask for permission to quote some of your paragraphs so they can be placed into the original document. May I?

As for the LRBs, I typed up this document specifically for FPS. Because I'm not fully experienced with LRBs yet, does it have any noticeable affect on increasing FPS?

I may be planning on writing an Accuracy document similar to this, but focusing on just accuracy so I'm not sure if LRBs belongs here or there or perhaps both.
 

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Vindicare, I would like to ask for permission to quote some of your paragraphs so they can be placed into the original document. May I?

As for the LRBs, I typed up this document specifically for FPS. Because I'm not fully experienced with LRBs yet, does it have any noticeable affect on increasing FPS?

I may be planning on writing an Accuracy document similar to this, but focusing on just accuracy so I'm not sure if LRBs belongs here or there or perhaps both.
Yes, you may, feel free to do what you will with it, and this 1 if you so choose :tup:

LRBs do indeed increase fps, as they reduce the amount of required hop pressure to lift any given weight of bb, there-by giving an increase in fps as its not being waisted trying to push the bb passed the hop nub...... obviously you cant predict how much fps gain you get as that is governed by the bend amount in your LRB vs the bb weight you are using, but be sure there will be a gain of some sort.

As an aside from this, long hops, of which ever form you choose, also benefit in the same way for similar reasons as LRBs to a certain degree, ie. hop nub pressure vs lift given...... the fps gain is marginal but if your after that last enth......, so may also be worth a mention :yup:
 

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I have not noticed the LRBs increasing fps, but we may be using different styles.
Yup, I noticed the gain when I fitted my LRB mod to my EMR, as I continued to use the .28s I always had.

I had to back the hop off as the LRB was now sending the bbs into orbit and when I cronoed again I had gained about 15 fps.....

Then I fitted my version of a long hop mod, and to stop the long hop/LRB combo sending the bb into the stratosphere the hop had to be set to bairly an angles touch, and with it I gained an average of another 10 fps.

Obviously if I'd chosen to use .4s right from the time I fitted the LRB I'd of noticed zip, and probably an fps dip from having to wind on the hop some more to help lift the bb :shrug:

I think they are a trade off, if your willing to stick to a lighter bb, you'll gain fps, if you are fitting the mods to be able to use heavier ammo, then the likleyhood is you will lose some fps, whether that would be the equvilent to the fps you would lose by just winding the hop on to get that heavy bb to fly flat, level and for any distance I do not know, but experience tells me it would like as not jam before you could get it anywhere near that of an LRB/L hop combo :shrug:

So surely this proves they would indeed give some benefit to increasing the fps, if in a more USEFUL way than just ''balls to the wall'' power......

Maybe its just me being anal about my limited fps and trying to extract asmuch USEFUL energy from those measely 350fps as is possible, As Ive written many a time and I've witnessed you write on various occassions.... sometimes its not about the power that makes the difference, its how you choose to deliver the, heavier than expected, projectile that counts:shrug:
 

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Well, that gain is not directly from the LRB, but from a lack of loss due to the hopup, though I think you may have said that... :p

Cranking the (regular) hop to get nice and flat at the same power level does cause jams, I've tried it. However, once you get above about 420 fps, the LRB effect still works, but the gains decrease until you hit about 650 fps. In fact, after about 800 fps, the LRB only helps if you are using steel bbs.

I knock down my power levels below 400 fps for a reason, it is my belief that the bb holds the most stable path when it is traveling a little slower. This has been proven again and again in my own testing, I can take very inaccurate rifles and just bump them down to 350 fps and they hit spot on. Basically, you're right. It only matters how you deliver that bb, not how hard it hits.
 

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There are some things I don't agree, but thats ok.

About the foam on stock, I can ashore you, they DO NOT increase FPS. Try it for yourself. And if you really apply physics (the right way), you will reach the same conclusion.

I think that your work lack a lot of basic scientific experiments. The majority of it is based on your BELIEVES, and many times on others too.

But your work have some interesting things that make me think, so thanks for the share!
 

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It does if it's done properly. Less energy is lost to vibrating the stock and more goes directly into the compression of the air in the cylinder. More compression equates to more energy transfer, which equates to a higher fps, QED.

Now, the difference will be so minute you won't likely notice it or measure it, but it is there.
 

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It does if it's done properly. Less energy is lost to vibrating the stock and more goes directly into the compression of the air in the cylinder. More compression equates to more energy transfer, which equates to a higher fps, QED.
I really dislike those "dogmatic trues" that some people almost impose on foruns, when this "true" is just a THEORY without realistic interpretations, and without conduction of proper testing and scientific observation in order to support them. What I know from proper testing on 2 rifles (stock Marui VSR and stock Well L96) is that you WILL NOT have even a 1fps increase.

Now, the difference will be so minute you won't likely notice it or measure it, but it is there.
LOL, so if you canot mesure it, how do you know it is there in first place? And even if you can´t mesuare it but it is there (atomic scale and quantum mechanics? LOL), why bother at all? We are talking onmeasurable increase of FPS.

Sorry for the strong words, mate.

Cheers.
 
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