Author Topic: How to build a high precision airsoft rifle  (Read 2688 times)

Offline nukeduster

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How to build a high precision airsoft rifle
« on: April 17, 2013, 11:33:44 PM »
As I've been building myself an AEG over the last few weeks, I've had debates with various people concerning Aeg's vs Polarstars vs daytonaguns/classic airsoft vs PTW's... and while there is a lot of firmly held believes about brand names, and what mechanism ultimately makes the BB leave the barrel, there is very little proof to support that the firing mechanism itself is chiefly responsible for high precision.

The big problem, as I see it, is that "best" has yet to be fully quantified. We all have witnessed a given person do amazing things with their X, Y, or Z gun, and often times (wrongly) start to attribute the amazing capabilities of the rifle solely with the firing mechanism, without thought to the rifle as a whole.
I propose that polarstars, aegs, ptws, and others' precision is largely a function of parts other than the firing mechanism itself. It is often the case that someone who was willing to spend money on a polarstar, or a PTW, etc, was also willing to spend money on improving the other aspects of their rifle, which incorrectly leads the perception that one rifle style is better than another.

So what makes one airsoft rifle better than any other given rifle? There are many variables that play into it, but in my opinion a good rifle will have (at least) these three characteristics:

1. It will be mechanically reliable.
It will fire every time the trigger is pulled without fail.

2. It will be precise.
It will hit the same spot over and over again as long as you don't move the rifle

3. It will be accurate.
It will hit where you are aiming at, all else being equal.


There are other factors: cost, fit and finish, presence of accurate trade marks, availability of replacement parts, and more to be sure.

However, I consider the first three to be paramount when deciding what rifle I will field personally. In order to achieve these top three items, I do the following when I am building a rifle.

1. Mechanical reliability; I choose parts that have proven to be reliable over time from many users. Ultimately money spent at this stage will be the best spent, as it will make sure that you can go out to the game every weekend and not worry about whether or not your gun will be down or not.
This list is for parts individually that I use and have had good success with. I don't recommend any particular pre-built gearbox options as they all require something in order to be 100% reliable.

Caveat: Manufacturers in airsoft have their ups and downs in terms of quality control, and while this list is accurate as of this writing for my experiences, the next batch from a given company could be utter garbage, so always do up-to-date homework before you buy. With that in mind...

Lonex: makes exceptionally good pistons, bushings, gearbox shells, gears, motors.. in fact, they're my favorite brand on the market at the moment for most parts.
Core: makes good gears, I'd stay away from their pistons
SHS: hit or miss quality, however for the most part their gears and metal rack pistons are good
Seigetek: Best gears on the market, period. They are expensive, but I defy you to break a set on anything under 4J.
G&P: Good motors. The rest of their stuff is good, if average for the price.
JG: Their neo motors are great, good quality gears.

There are many other brands that are ok, good, or even great, but many of them are simply re-brands of the above manufacturers.

2. Precision:
In order to gain precision, you need repeatability. That is, every time you pull the trigger, the bb will follow the same rough path every time.
This is a more complicated area, but chiefly you need the following:

a: A good air seal. Check to ensure that you have properly assembled everything that there is no air leaks anywhere in your system. Properly stretched piston o-rings, a good o-ring air nozzle, and good hop up unit are key to this. There are other techniques involving anything from silicone glue to teflon tape to improve air seals throughout the system.

b: A high quality barrel. This does not mean a tight bore by any means. In fact tighter is worse. You generally want at LEAST .05mm of barrel diameter difference between the ammo you plan on running, and the bore of your barrel. Keep it clean, and keep it DRY. Also, ensure that it is supported for its full length. Barrel harmonics play hell on precision on guns that have un-supported inner barrels hiding inside mock-suppressors. They may look tacti-cool, but they hurt precision.
Also, as  a general rule avoid coated barrels. Stainless steel is the best, followed by brass, followed by aluminum, followed by everything else, in my opinion.

c:A high quality hop up bucking/packing. There are various styles out there that are good, but generally flat-hop, bridge-hop, and r-hops are the best that are out there. Choosing the appropriate sleeve that matches your FPS output is also important.

d:High quality ammo.  Its like having a $100,000 sports car, and being too cheap to buy premium fuel. It might run, but it won't run to its potential. Cheaping out on ammo is probably the worse thing you can do. Whats the point of investing all the time and money into a gun and time traveling to games only to miss your target because you saved a dollar the day before on a bag of cheaper ammo?

3. Accuracy: Buy optics that make sense for your intended role, and zero them in. Airsoft does not have enough recoil to seriously jostle optics around like real-steel but never-the-less make sure that your chosen optics/sights can take a couple bangs without losing zero. Once you have precision nailed down, properly zeroed optics is the only mechanical aspect of accuracy that comes into play. The rest of it, is up to you, the shooter.

This may be changed and updated from time to time, but as it is now it reflects my 13 years of experience with building and tuning airsoft rifles of all breeds.
« Last Edit: August 02, 2013, 03:37:08 PM by nukeduster »

Offline Old Dog

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Re: The benchmark of a well-made airsoft rifle
« Reply #1 on: April 18, 2013, 12:53:07 AM »
One of the best posts seen in a long time, much positive knowledge for all, a good saver :)

Thank YOU ND :)
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Offline Wolf Bane

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Re: The benchmark of a well-made airsoft rifle
« Reply #2 on: April 18, 2013, 09:36:01 AM »
Thanks for the info.
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Code Name: Wolf
Armory: UTG L96, CYMA M14 SOCOM, JG M4 S-System, KJW P229

Offline Tiedyeftw

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Re: The benchmark of a well-made airsoft rifle
« Reply #3 on: April 18, 2013, 03:01:50 PM »
This is so well-put together man, love it.

But i feel like "precision & accuracy" is a bit redundant.
Personally, i think that the three defining characteristics of a great rifle are:

1. Mechanical Reliability
2. Mechanical Proficiency
3. Precision

Any average rifle will perform at an okay standard. A rifle can be Reliable and Precise, but to stand out from the crowd in a sea of average rifles, it must be Proficient.

With being Proficient, i mean that:
A rifle must Perform at a higher level than most rifles. A gun should have internal components that give a faster response time, work together more efficiently, that maintain their integrity with ease.

There are many players, for example, that can build a Reliable gearbox using 18:1 gears, a good motor, and a strong piston. but to have your rifle PERFORM at a level that is beyond average, Upgrades must be done to produce Proficiency in 1. trigger response 2. rate of fire, and 3. muzzle velocity.
« Last Edit: April 18, 2013, 03:07:00 PM by Tiedyeftw »
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Offline XavierMace

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Re: The benchmark of a well-made airsoft rifle
« Reply #4 on: April 18, 2013, 03:29:06 PM »
Trigger response, rate of fire, and muzzle velocity....  None of those are evidence of a well made airsoft gun.  Just a higher power battery/gas.

Offline nukeduster

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Re: The benchmark of a well-made airsoft rifle
« Reply #5 on: April 18, 2013, 04:08:08 PM »
This is so well-put together man, love it.


Thank you.

But i feel like "precision & accuracy" is a bit redundant.
Personally, i think that the three defining characteristics of a great rifle are:

1. Mechanical Reliability
2. Mechanical Proficiency
3. Precision

Any average rifle will perform at an okay standard. A rifle can be Reliable and Precise, but to stand out from the crowd in a sea of average rifles, it must be Proficient.

I'm not sure what you mean by proficient? People can be proficient marksmen, but rifles can't in and of themselves be proficient at anything.

There is a VERY distinct and important difference between precision and accuracy. While I could attempt to differentiate it more than I have already, it would probably take several paragraphs. So, like they say, its worth 1000 words:



With being Proficient, i mean that:
A rifle must Perform at a higher level than most rifles. A gun should have internal components that give a faster response time, work together more efficiently, that maintain their integrity with ease.

There are many players, for example, that can build a Reliable gearbox using 18:1 gears, a good motor, and a strong piston. but to have your rifle PERFORM at a level that is beyond average, Upgrades must be done to produce Proficiency in 1. trigger response 2. rate of fire, and 3. muzzle velocity.


I'll respectfully disagree with this too. Trigger response, and RoF are (mostly) functions of a high wattage system. Via either high voltage, amperage, or both.

High muzzle velocity is a function of spring choice. None of these things will make a gun perform more accurately and in fact the RoF issue will negatively impact piston and gearbox life.
It might shoot more pleasingly to you, but none of these make it more accurate nor precise, and thus does not make it put rounds on target any better.

It may put out more bbs per second, farther, but without precision and accuracy, they're just a beehive of bb's going a long distance, while missing the target.

I have this discussion a LOT in fact, especially when I was on the range giving a class or helping out. There are a lot of professionals out there with plenty of muscle who can keep the rifle/pistol trained on the same spot over and over again, but its sight alignment sight picture, trigger control, etc, that makes them accurate. Over and over again they can make mistakes that makes the bullet hit the same, but wrong spot over and over again. They're precise, but not accurate.
« Last Edit: April 18, 2013, 04:21:44 PM by nukeduster »

Offline Tiedyeftw

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Re: The benchmark of a well-made airsoft rifle
« Reply #6 on: April 18, 2013, 07:42:26 PM »

I'll respectfully disagree with this too. Trigger response, and RoF are (mostly) functions of a high wattage system. Via either high voltage, amperage, or both.

High muzzle velocity is a function of spring choice. None of these things will make a gun perform more accurately and in fact the RoF issue will negatively impact piston and gearbox life.
It might shoot more pleasingly to you, but none of these make it more accurate nor precise, and thus does not make it put rounds on target any better.

It may put out more bbs per second, farther, but without precision and accuracy, they're just a beehive of bb's going a long distance, while missing the target.

I have this discussion a LOT in fact, especially when I was on the range giving a class or helping out. There are a lot of professionals out there with plenty of muscle who can keep the rifle/pistol trained on the same spot over and over again, but its sight alignment sight picture, trigger control, etc, that makes them accurate. Over and over again they can make mistakes that makes the bullet hit the same, but wrong spot over and over again. They're precise, but not accurate.

I understand what you're saying. I just feel that 'Precision and Accuracy' sound like kind of the same thing.
Precision is when your rifle can fire bbs at the same spot, again and again, staying accurate and on target each and every time. (thanks to the upgrades in inner barrel quality, hopup, airseal, bucking, and being sighted in correctly).
     But just by definition, to be "Proficient" means that one is better at something. More skilled.. and the way i use it- is to demonstrate a prospect of Higher Quality.  I guess Proficient is a bit geared to human characteristics, but you can think of it as being synonymous with the word "efficient" i suppose..

But i maybe i was a bit vague when i listed my explanation. Let me be a little more specific:
lets say that we have two M4's. Both have been upgraded to shoot both Precisely and Accurately.
And each of the M4's have DIFFERENT, but Reliable, strong internal components that will not break on them.
They EACH run on Specifically, a 7.4v 1400mah Lipo battery. Nothing else.

Now. Let's say that each of the M4's have identical cylinders, springs, and airnozzles. and Each gets an identical FPS reading of 330.
BUT lets say M4(A) has the following components:
Azimuth piston w/ steel teeth, 18:1 ratio gears, g&p m120 motor, and a G&G trigger mech.

Now lets talk about M4(B). Its components are as follows:
Azimuth Piston w/ steel teeth, 13:1 ratio gears, Echo 1 High Torque Motor, and G&P trigger mech.


M4(A) chronos at 16 RPS, with okay trigger response. Totally reliable.
and
M4(B) chronos at 18rps, with INSTINTANEOUS trigger response. Totally reliable.


In a skirmish, M4(B), with NO human involvement-ONLY focusing on rifle's alone, will always have the upper hand. Because reaction time and speed are MAJORLY the deciding factor in a split-second firefight.
Even though M4(B) only shoots slightly faster (rps wise), it doesn't make a major difference in skirmishes or wear&tear. However, having superior functionality over M4(A) makes M4(B) come out on top, every time.

I realize that while most people suck, there are still some genuine characters that exist out here. I'll show my appreciation by being genuine in return.
Love the sport.

Offline nukeduster

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Re: The benchmark of a well-made airsoft rifle
« Reply #7 on: April 18, 2013, 08:58:09 PM »
1/18th of a second vs 1/16th of a second is a difference is 0.00694 seconds between the two guns you just listed. That is a faster response time than the human central nervous system can process stimuli, so the idea that that small of a difference will win a firefight is not scientifically accurate. Assuming they pulled the trigger at the same time, the difference would not be perceivable about who hit who first, not that that matters if you're both out anyway.

I do however know what you are saying, and its just that RPS doesn't make a gun better, thats a matter of preference. I prefer around 9RPS in my guns, because running low-caps and mid-caps, I can lay suppressing fire down for 9-15 seconds non-stop when I need to before running out of ammo, vs a high RPS gun which will have no suppressing fire capability in a mil-sim game using midcaps.

That being said, 18rps isn't exactly high RPS compared to the 55+ RPS guns I've played with in the past before tiring of them (which by today's standards are still only average at best when compared to todays 80+ rps capable Aeg's).

TL;DR: All else being equal, rate of fire is a preference, not a game changer. Take an M4A1 vs the M733. They're essentially the same gun with different roles in mind, and are equally good at killing people.

Offline Exarach

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Re: The benchmark of a well-made airsoft rifle
« Reply #8 on: April 18, 2013, 11:14:44 PM »
Jesus, do none of you guys look anywhere but aa hahahah? Your whipping a deeeead horse. Look at ASM/Airsnipe/Old ASF posts.

hahah, this forum is starting to look like asf. Where did AA go>?


Its all hop/seal/barrel peeps.
Check out the pages and pages of data on barrel type and diameter comparisons, different hop configurations and such.

Theres even supertech stuff with formulas for range/fps per volume, ect.

My favorite is the weight to range guide haha, Preferred fps per weight based on X fps fired 100 times.

I won't knock this thread for what it is, as I love writing airsoft reviews/techchat as well, but mano, don't reinvent!

Start from whats there and go higher.
« Last Edit: April 18, 2013, 11:20:12 PM by Exarach »
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Offline nukeduster

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Re: The benchmark of a well-made airsoft rifle
« Reply #9 on: April 20, 2013, 03:46:09 PM »
Jesus, do none of you guys look anywhere but aa hahahah? Your whipping a deeeead horse. Look at ASM/Airsnipe/Old ASF posts.

hahah, this forum is starting to look like asf. Where did AA go>?


Its all hop/seal/barrel peeps.
Check out the pages and pages of data on barrel type and diameter comparisons, different hop configurations and such.

Theres even supertech stuff with formulas for range/fps per volume, ect.

My favorite is the weight to range guide haha, Preferred fps per weight based on X fps fired 100 times.

I won't knock this thread for what it is, as I love writing airsoft reviews/techchat as well, but mano, don't reinvent!

Start from whats there and go higher.

Most people don't read some of the more technical forums for whatever reason, and I wanted to share some of my personal experience on this subject just to inform the newbies and vets alike on information that is out there in the internet but condense it in a local forum.

I'd rather have more guns out there that can shoot 300+ feet accurately and reliably to make airsoft that much more of a tactical challenge, than get lazy because I can outreach half the field.

Offline nukeduster

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Re: The benchmark of a well-made airsoft rifle
« Reply #10 on: August 02, 2013, 03:36:28 PM »
Bumping this due to recent relevant questions.

Offline Hoss

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Re: How to build a high precision airsoft rifle
« Reply #11 on: August 09, 2013, 12:13:40 AM »
Bioshot v.s. Biovals??
 
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