Spring into Spring with Springs
Unlocking the Science Behind High Powered Springers
Table of Contents
Intro – Why We’re Writing This
There’s a lot of ideas and opinions out there about what makes a blaster perform well. Here, we hope to share some of the ideas that we’ve gathered over the years and what we’ve discovered with building blasters in our shop. This will be a wordy lengthy post. We’ll update this post to keep a current record of techniques and principles as they develop in the hobby. Feel free to contact us if there’s anything we’ve missed.
We’ll first identify principles, define and explain them, then provide tips on how to maximize them.
Discussion can get very technical and sciency very quickly if we dive really deep into the physics and energy mathematics that occur with spring powered blasters. We hope to help readers realize that building a sufficient knowledge of the key principles is actual quite simple and easy to understand. With all the options available, decision paralysis can creep up and many people can be left feeling like they can’t get good performance out of their blasters or don’t have the time to do all the possible research or time to do all of the trial and error to learn themselves. Knowing exactly what performance you’ll get out of a specific set up in a blaster can be tricky since there are a lot of variables and not a one-size-fits-all answer, but the general principles are actually quite easy to get a grasp of and the results speak for themselves.
Let’s dive in!
What Do We Mean by “Performance”?
Performance can mean different things to different people depending on preference and situation. Important factors can be power, accuracy, reliability, durability, weight, size, ergonomics, rate of fire, sound, and many others. To keep things simple for now, we’ll focus on the first two: power and accuracy.
There are several universal variables that affect nearly all springers. We’ll look at the variables that relate to Power and Accuracy separately.
First up, blaster power.
Springer Blaster Power – How Do We Define it?
Blaster power is most often measured as the speed that a dart is fired. Speed here we’ll meaure in feet per second for FPS. A more powerful blaster will shoot harder and with a higher muzzle velocity or FPS.
Power is often increased or decreased to meet event regulations depending on the event type or venue. Blasters for casual around the house or with typical foam blasters shoot in the range of 60 FPS to 100 FPS. These are the majority of blasters you’d find off the shelf and big box retail or toy stores. A lot of Humans vs Zombies (HvZ) events are held in close quarters and college campuses so many of these events have a lower limit of 130 FPS. Mid power events or outdoors events often have higher limits. The Utah Nerf Foam Flingers (UNFF) plays with 160 FPS limit. The 150 or 160 limit allows for higher powered off-the-shelf blasters to be used such as Dart Zone blasters, low powered Worker Harriers, or standard low powered homemades like the Caliburn or Talon Claw. Above that, you have 200+ FPS events typically outdoor or at longer engagement distances. Depending again on the desired gameplay or size of venue available, high FPS limits can be 250 or 300.
You could probably guess that the higher the FPS, the more difficult it is to tune a blaster to hit that FPS. The number of blasters that hit 300 FPS easily is much lower than the number of blasters that can hit 100, 150, or even 200 FPS. The principles behind getting top performance, or power, out of a springer blaster are below.
The key factors that affect all spring powered blasters are: spring, barrel, air-seal, and volume.
Blaster Air Volume
Volume is usually limited by the blaster design itself and thus the hardest to change.
The principle here is: the blaster with more volume will be able to achieve higher performance (or performance ceiling). If you want to build a high powered setup, you need high potential. Since there’s not much we can do to change our volume, we’ll leave it at that. However, it is worth it to note the blasters that DO have high volume. Those would include the ZWQ Baize, Caliburn, and second to those, the SLAB, Lynx, Talon Claw have medium volume, while blasters like the Zinc, FireRat, Viper have small volume in comparison.
Note: It’s the usable volume we care about, not dead space. Volume between the end of the plunger and dart in the barrel such as a redirect piece is air that isn’t available to be used to push the dart. Instead, that dead space will act against performance because that air will also need to be pressurized along with the air inside the barrel. More on air pressurization later.
Here’s a chart comparing different blaster air volumes in millileter (ml) or cubic centimeter (cc). 1 cc is equal to 1 ml or 0.033814 US Fluid Ounces.
Springs: That’s what we’re here for!
For springs, the stronger the spring, the faster the air in the Plunger Tube will be pushed down the barrel and the greater the obtainable pressure can be behind the dart. So an easy way to boost your power is to use a stronger spring. The limitation of using a stronger spring is the strength of the user, durability of the blaster to withstand the higher impact force, and the physical space constraint of available room in a blaster to fit the spring.
Springs come in all lengths, diameters, wire thickness, and spring strength. Generally a longer spring will be stronger given the other parameters are the same. Similarly, a thicker wire diameter will result in a stronger spring. Common spring sizes can be broken into a few commonly used categorizing terminology.
Caliburn springs, often referred to as K-series springs, are around 11″ in length and ~1″ and smaller in diameter. High quality springs like the Turf Pro25 and Turf Pro26 are examples. These springs are not often referred to by their strength or wire diameter, but simply called by their item number.
ZWQ/Worker/Narrow/Nexus springs are ones that have a very small outer diameter, about 1/2″. N type springs are also categorized here, such as N20 springs. The Dart Zone line of blasters such as the Nexus Pro use these narrower springs. These are often referred to by their wire diameter, such as 1.5 or 1.8 spring.
Talon Claw springs are shorter springs of similar diameter to Caliburn springs. They’re often available in similar diameters as Caliburn springs, but are cut down shorter to fit in a small plunger tube volume. These springs are used in the Talon Claw, Lynx, and most other homemade builds that have similar sized plunger tubes. Most of these blasters can also use Longshot springs interchangeably and are referred to by their spring rating in Kilograms, such as 10kg or 16kg spring unless the spring is just the equivalent of a shorter Caliburn spring, such as SF25 or cut down K25.
Longshot springs are often short like Talon Claw springs, but wider than Caliburn springs. Most Longshot springs are wider than 1″ in diameter, but some can come in smaller diameters, but are much less common. Like Talon Claw springs, these springs are used in the Lynx, SLAB, Talon Claw, and other blasters with similarly sized plunger tubes. They are also referred to as 10kg or 16kg spring.
That’s already a lot of words and information, but basically, the key aspects of a spring are length, diameter, and force/strength. Some springs are measured in Kilograms (kg), wire diameter (millimeters), or just by a name like K25 or K26.
How to Choose a Spring
1. Make sure it will fit in the blaster you want. That would be length and diameter.
2. What general power level you’re looking for. Each spring will give a range of performance depending on the rest of your blaster set up such as barrel and airseal. For maximum power, use the largest spring you can prime and that will fit. Some common value ranges are in the table below.
Common Spring Sizes:
Worker 28N Prophecy Retaliator Long Spring
Nexus Pro Spring
Max Striker Spring
Worker Harrier, 1.4×250
Worker Harrier, 1.4×280
ZWQ Baize S100s Default Spring – 1.5
Worker Harrier, 1.6×300
Worker Harrier, 1.6×250
ZWQ Baize S100s Upgrade Spring – 1.7
Worker Swift Spring, 1.8×350
Worker 22KG Longshot Spring
Air-Seal – Second Universal Performance Factor
Spring powered blasters use springs to compress air creating pressure that then propels the dart. Like most things, compressed air will take the path of least resistance. If there isn’t a sufficient air seal, air will leak and escape somewhere else other than behind the dart causing a drop in power. The common places for air leak is the Plunger/Piston and whatever is on the other end of the Plunger Tube (Usually a Rambase/Pusherbase or some sort of redirect to move the air from the Plunger Tube to the dart or barrel). Getting a good airseal on the Plunger/Piston is why many people use Machined Parts.
The principle is this: the air behind the dart will move the dart down the barrel until the dart leave the muzzle. You want that air to move the dart as fast as possible down the barrel. Two factors affect this. 1: the speed of the air. 2: the pressure of the air.
An ideal Plunger will have a balance of airseal and speed. A Plunger that uses an o-ring that presses tightly against the Plunger Tube will seal well, but doesn’t move with enough speed to move the air fast enough to fire the dart. On the other hand, a Plunger that does not seal will move very fast with no resistance, but the air will leak around the Plunger instead of being used to push the dart.
The golden ratio is the fastest Plunger possible that generally holds air for a few seconds. This comes down to trial and error mostly.
Airseal can also apply to components ahead of the Plunger and Plunger Tube. However the blaster is designed, everything after the Plunger should be airsealed up tight. This could be an air redirect piece (Zinc, SLAB, Lynx, etc) or a ram/pusher and rambase (Caliburn, TalonClaw, Baize, Kirin).
How to Improve Air-Seal
1. Use proper lube. It should NOT leave black residue over time. Dirt can build up, but if you get a lot of black like rubber type colored gel like substance, you need to change your lube. It should be Silicone or O-Ring safe. Don’t use anything petroleum based and be weary of additives like propellants in aerosals.
2. Surfaces should be clean of debris and oils and dust.
3. Proper contact between o-ring and sealing surface (not too tight, or too loose). If there isn’t enough contact between an o-ring and sealing surface such as Plunger Tube, a common remedy is to use Teflon tape around the base of the o-ring groove so that the o-ring presses against the Plunger Tube slightly more. Using a new o-ring or wider o-ring is also an option. As an o-ring is impacted over time, it can degrade and become smaller, so using a new o-ring can also help.
Upgrading to a Machined Rambase or Machined plunger can help.
Barrels – of Monkeys
Barrels play a large role in both overall power and accuracy. For power, you want a barrel that does not impose excess friction on the dart slowing it down, but also one that allows pressure to build up behind the dart, accelerating the dart.
Generally, a longer barrel will give more power because it will have more time for the dart to accelerate. However, a barrel that is too long will create too much friction on the dart.
The ideal barrel will be short enough that the plunger reaches the end of its travel around the same time the dart exits the barrel. This means that the plunger speed will have stopped and the dart would have no more pressure applied to it from the air volume.
A longer barrel with low friction is what you want. Low friction can be achieved by using a material with a low friction coefficient such as Brass or Anodized Aluminum, or by applying a smooth wax such as Lemon Pledge or other wax to the inside of the barrel.
The rule of thumb is: use the longest barrel appropriate for the air volume of Plunger Tube with the lowest friction you can. A tighter barrel will give a better airseal between the dart and barrel, but may impart too much friction. Since the formula we want is a balance of volume and pressure, a tighter barrel can give higher performance with a shorter length and greater pressure similarly to a looser longer barrel with less pressure. Trial and error would be your best friend here.
Summary of Important Barrel Attributes to Consider:
Length
Tightness
Common Sizes: 0.527 Alu | 13mm Alu | 0.509 Alu | 17/32 Brass | 0.495 Alu
Smoothness:
Friction Coefficients
Aluminum 0.9
Anodized Aluminum 0.3
Teflon Coating 0.14
Brass .5
Air Volume of Plunger Tube and Barrel
Accuracy (Technically Precision)
Precision means tight grouping. That’s generally what most people actually mean when they say accuracy.
Dart Quality
Accuracy of a blaster depends a lot on the quality of dart. Consistency shot to shot is where accuracy comes from. Using a good quality dart or at least a consistent type and darts of equal wornness will help that consistency.
Generally speaking, short darts are more accurate than long or full-length darts because they’ll have less instability in flight.
In addition, firm foam and new foam will create a better air seal in your barrel and the head shape and size also makes a difference.
A lot of people have done testing on different darts, but we at Frontline Foam have reached similar conclusions to Bradley Phillips. We find the best darts to be Worker Gen3+ Darts.
Barrel and SCARs
The second factor that influences consistency is the barrel.
That can be broken down into two parts. The barrel itself, and the muzzle device or muzzle break.
What causes instability and inconsistency in shot to shot performance are inconsistent darts and turbulance in the barrel due to either airflow or other factors.
As the air in a barrel pushes a dart down the barrel and out the muzzle, excess gas can be released unevenly from the muzzle behind the dart, causing the dart to be knocked off course. A properly lengthed and tightness of a barrel can help minimize the volume and speed of this excess gas. The gas would loose speed as the dart continues down the barrel.
However, a barrel that is too long can impart friction on the dart so an additional method to control this distortion is to use a ported muzzle or muzzle device that can vent the excess gas. This means the barrel can remain short, with the gas being expelled from behind the dart BEFORE the dart leaves the muzzle resulting in less air distortion to throw the dart off course.
Muzzle Devices
A common way to maintain dart stability in a generally easier way despite these factors is to use a Centering, Aligning, Rotating (CAR) muzzle device rather than just porting. Porting is also harder to manufacture into a barrel than just adding a muzzle device.
A CAR adds stability to a dart by imparting a slight spin to the dart. This spin helps to push the dart through the turbulance we mentioned before and helps the dart overcome additional turbulance that may be present in the dart’s path such as any circulating air or wind in the environment.
CAR devices are often referred to as P-Car, S-CAR, or B-CAR. The letter refers to the method that imparts the rotation on the dart. P means printed ridges inside the muzzle device, S means string such as fishing string that can often be adjusted to impart a different amount of spin on the dart, and B meaning Bearing or flange bearings which are small ball-bearing wheels that contact the dart and spin it a certain degree.
Each of these can impart spin, but can also impart a bit of friction since the rotation is created by contacting the dart.
An adjustable SCAR is extremely useful since the twist rate can be changed to match your power, volume, etc. The Worker Adjustable SCAR is a good one.
Larger SCARs can give a mock “suppressor” type of look at provide a longer distance for the dart to spin and more room for the excess gas to vent.
Overall, each Muzzle Device is different and has its pros and cons. A BCAR often gets high FPS than a SCAR or PCAR, but are not adjustable and more expensive.
Conclusion
For max power and accuracy, you want to limit as many variables of inconsistency that you can. Darts, barrel, spring compression, and muzzle device can all contribute to those. We hope this write up can help guide you in your spring blaster build decisions or at least you found it entertaining to read.
Hitting a 2 inch target consistently 50 feet away is doable as we’ve shown in past videos, so if you’re not quite getting the performance you want, don’t give up! The solution for your setup is out there and just needs to be found!
Nerf on!
– Derrikk
