Springs 

There are a lot of airsoft springs that are available in the market today. They are often coded or named with numbers that often leave buyers confused… Not to mention a each manufacturer have a different code for a spring for a given rating. Anyway here is a guide to help buyers to choose which spring to buy and an expected FPS output after the spring has settled (usually after a hundred cycles an airsoft spring settles and maintains a certain fps output till it eventually wears out)

This article removes most of the guesswork when you are upgrading your AEG. Provided some FPS baseline so that you'll know what to expect from a particular set-up. Also included some useful tips that would help you decide what to put inside your gearbox (mechbox) to improve durability and lifespan.

SPRINGS: (Approximated Settled Spring FPS using .20gBB)

Stock Gun (brand new gun): 270-290 FPS (depends on Brand/Manufacturer)

Stage1 Upgrade: M100 / SP100 / PDI120% = 330-350 FPS

Stage 2 Upgrade: M120 / SP120 / PDI170% = 390-410 FPS [stable with .20gBB ]

Stage 3 Upgrade: M130 / SP130 / PDI190% / PDI210% = 440-460 FPS [ok with .20gBBmin but more stable with .23gBB]

Stage 4 Upgrade: M140 / SP140 / PDI240% = 470-490 FPS [ok with .23gBBmin but more stable .25gBB ]

Stage 5 Upgrade: M150 / SP150 / PDI270% = 510-530FPS [acceptable with .25gBB but would suggest .28gBB for better accuracy]

Stage 6 Upgrade: M160 / SP160 = 550-580 FPS [.30g/.36gBB accurate]

Stage 7 Upgrade: M170 / SP170 = 580-600+ FPS [.36g/.43gBB accurate]

Accuracy troubleshooting in terms of BB weight

BB hits everything but the target

Cause:BB too light for the FPS rating

BB drop without reaching expected range

Cause:BB too heavy for your guns power rating

Gears

Gears have no effect whatsoever on your power rating, it only affects "Rate Of Fire"

Common gear-to-spring set-ups

High Speed/ Fast Gears: Can handle from stock springs up to M100/SP100/PDI120% (Usual replacement for stock gears0

Torque Up Gears: Can handle M130/SP130/PDI190%-210% or lower spring ratings

Torque Up Gears or Super Torque Up Gears: Can handle M140/SP140/PDI240%

Ultra Torque Up Gears: Can handle M150/Sp150/PDI270%

Ultra Torque Up Gears and Infinite Torque Up Gears: Can handle M160/SP160 (Will need some for Version 2 Gearbox/Mechbox clearancing to fit)

Infinite Torque Up Gears: Can Handle M170/SP170 Springs (Will need some for Version 2 Gearbox/Mechbox clearancing to fit)

Gear Set Life Spans and Durability

Stock Gears: They are low cost and provides good rate of fire. But are just casted from "weak" alloy so they are not as durable as steel gears. They can handle 130/SP130/PDI190%-210% springs but only on a limited time (depends on use) before wearing out (the Sector gears gives in first and will damage the piston body in the process).

Flat Gears (Torque Up and Super Torque Up): Cheaper than helical gears and a lot easier to shim but are a bit on the noisy side. Durable enough becaue they are made of steel (but manufacturer also plays a big part, have seen defective/weak batches).

Helical Gears (Torque Up and Super Torque Up): A bit expensive than the flat gear version and a bit tricky to shim, but would provide a smoother (sound) operation compared to their flat gear counterpart.

Batteries

Batteries also have no effect whatsoever on your airsoft gun's FPS, it only affects Rate Of Fire and it's ability to drive the motor to pull heavier springs.

Voltage: Affects ROF and ability to pull heavy spring (But this will also depend on the motor that you're running)

mAH (milli-Amp-Hours): This is pretty simple, the higher the mAH of your battery the longer the it will sustain your AEG's operation before recharging.

Standard Battery sizes and configuration for Airsoft Gun Types

M4A1 Rifle: 9.6v 1700 mAH (Fat Long AA size) or a V-type (config) 12v 1700 mAH (max)

M4A1 Patriot: 12v 1700 mAH (Fat Long AA size) on a "circular configuration"

G36C (Marui): 9.6v 1500 mAH (Fat AA) 12v 1700 mAH (max)

AK47/Spetz: 10.4v 2400 mAH (Sub-C) 12v (max)

M16A1/A2/VN/SR16: 9.6v 2400 mAH (Sub-C) 13.2v (max)

CAR15: 8.4v 600 mAH (small) 1500 mAH (max) (Fat AA) 2 Separates

P90: 9.6v 1700 mAH (Fat-long AA) J-type configuration

G3A3/G3SG1/MP5A4/MP5SD5: 9.6v 2400 mAH(Sub-C) Straight configuration

MP5SD6: 9.6v 1500 mAH (Fat AA) V-Type configuration

MP5A5: 9.6v 1100 mAH (slim) nun-chuck configuration

Steyr AUG: 9.6v 1700 mAH (Fat-Long-AA) Box Type configuration

PSG-1: 10.8v 1500 mAH (Fat AA) 13.2v (max)

Tokyo Marui M14: 8.4v standard large type battery But would be able to fit a custom 9.6v 2400 mAH battery by clearancing the rifle stock.

GNG M14: Battery compartment so spacious you could fit any large type battery without any rifle stock modification.

Approximate Battery-to-(number of airsoft BB rounds) Capacity: NiCd (Using M120 Sping and an EG1000 motor)

9.6v 600mAh = <500 rounds (Small) Sanyo KR600AE 9.5mOhm Internal Resistance

9.6v 1100mAh = 1,000 rounds (Slim) Sanyo KR1100AAU 19mOhm Internal Resistance

9.6v 1500mAh = 1,400 rounds (Fat AA) Sanyo KR1500AUL 16mOhm Internal Resistance

9.6v 1700mAh = 1,800 rounds (Fat-long AA) Sanyo KR1700AU 17mOhm Int. Resistance

9.6v 1900mAh = 2,400 rounds (Sub-C) Sanyo N-1900SCR 4mOhm Internal Resistance

9.6v 2000mAh = 2,600 rounds (Sub-C) Sanyo KR-CH 6.5mOhm Internal Resistance

9.6v 2400mAh = 3,100 rounds (Sub-C) Sanyo CP-2400SCR 4.5mOhm Internal Resistance

9.6v 3000mAh = 3,800 rounds (Sub-C) Sanyo HR-SCU [Ni-MH] 5.3mOhm Internal Resistance

Approximate Charging Time on 1000mAh Output Charger

600mAh = 36mins(min) 42mins(std) 48mins(max)

1100mAh = 1hr 6mins(min) 1hr 19mins(std) 1hr 30mins(max) 1500mAh = 1hr 20mins(min) 1hr 48mins(std) 2hrs 7mins(max)

1700mAh = 1hr 42mins(min) 2hrs(standard) 2hrs 24mins(max)

1900mAh = 1hr 53mins(min) 2hrs 18mins(std) 2hrs 43mins(max)

2000mAh = 2hours(minimum) 2hrs 24mins(std) 2hrs 48mins(max)

2400mAh = 2hrs 23mins(min) 2hrs 54mins(std) 3hrs24mins(max)

3000mAh = 3hours(min) 3hrs 37mins(std) 4hrs 13mins(max)

*Charger should be 1 to 3 volts higher voltage than total battery voltage
DISCHARGING: Number of batteries in a Pack = Max discharge volts.
(ex. 9.6v = 8cells in a pack = 8.0v is the maximum discharged voltage)

Piston Body

Piston Body lifespan will depends on spring rating and usage (full auto operation over a prolonged period will definitely cut it's life short)

Spring Ratings and Matching Piston Body Type/Brand

M140 Below (Author's Suggestion)

1. ICS Aluminum Piston Body (piston lightening modification suggested to reduce weight)

2. Systema Aluminum Piston Body (Teflon Coated) (piston lightening modification suggested to reduce weight)

3. Deepfire Piston Body(Made with Nylon and Fiber not polycarbonate) with titanium teeth(last teeth)

4.Guarder Polycarbonate Piston Body (Blue)

5.Tokyo Marui Stock Piston Body (polycarbonate)

Note: Systema red polycarbonate piston body is weak stay away from it.

M140-150/SP140-150: Aluminum Piston Body (Have been proven and tested to withstand abuse without damage to gears, since the material is softer than the material used for the gears)

M150/SP150 and Above: Deepfire Piston Body with titanium coated teeth insert; this will withstand the pressure of heavy springs. But there have been reports of damage on the plastic part where the titanium teeth is inserted when used with M170/SP170 springs but putting adhesive on the notch has been proven to remedy this problem.

CYLINDERS

(cylinderVolume-to-barrel-ratio) 2 is to 1 (standard)

Tokyo Marui Stock Cylinders:

1. Closed Cylinder = 27.1cc 450mm(min) 580mm(max) barrel length
2. XM Cylinder = "4/5 hole" = 364mm(min) 460mm(max) barrel length
3. M4 Cylinder = "3/4 hole" aka Type-2 17cc - 229mm(min) 430mm(max) barrel length
4. MP5K Cylinder = "mid hole" 9cc 110mm(min) 170mm(max) barrel length

Systema NB Standard and BoreUp Parts
1. Type-0 Cylinder (closed) fits M16-A1,VN,A2,G3-A4,SG1,SIG550,AUG
2. Type-1 Cylinder (tip hole) for XM177, M4, AK47, AK47S, SIG551
3. Type-2 Cylinder (XM hole) for MP5-A4,A5,SD5,SD6, MC51,SIG552
4. Type-3 Cylinder (M4 "3/4" hole) for MP5 PDW
5. Type-4 Cylinder (MP5K mid hole) for MP5K
*BoreUp Closed 29.4cc = 500mm(min) 600mm(max) barrel length

KM Cylinder Parts:
*Intercept Cylinder 59 barrel length from 450mm to 590mm (Type 0)
*Intercept Cylinder 45 barrel length from 250mm to 450mm (Type 2)
*Intercept Cylinder 25 barrel length from 100mm to 250mm (Mid-hole)

Airsoft Gun Barrel Lengths (inner Barrel)

650mm/25.59in PSG-1 (extended)

595mm/23.42in APS2 OR

589mm/23.18in PSG-1

550mm/21.65in M16A1/VN/A2,AUG (extended)

534mm/21.02in Sig550

515mm/20.27in GNG M14

509mm/20.03in M16A1/VN/A2,AUG

500mm/19.68in TM M14

472mm/18.58in Famas SV/F1 469mm/18.46in G3-A3/A4,SG1

455mm/17.91in AK47,AK47s

444mm/17.48in M60 407mm/16.02in M4A1 M653E2 (extended)

395mm/15.55in APS2 SV

369mm/14.52in HK51

363mm/14.29in M4A1,RIS,SR-16,XM177ED,Sig551

300mm/11.81in M1A1,AKBetaSpetz, M733

285mm/11.22in MC51

247mm/9.72in Car15,P90,G36C, SIG552

245mm/9.64in UZI - 400mm/15.74in (extended)

229mm/9.01in MP5A5/A4/SD5/SD6

170mm/6.69in MP5K-PDW (extended)

141mm/5.55in MP5K-PDW

110mm/4.33in MP5K