GGWPTECH // Field Tools — PH Edition

Airsoft Upgrade Estimator

Estimate FPS, joules, rate of fire, and effective range from your gearbox and gas setup — then check it against field limits for the Philippines, international (US/EU-style) fields, or Japan's ASGK legal limit, before you're standing at the chrono table.

Gearbox & Barrel

Springi

Baseline FPS shown is calibrated at 0.20g BB, then adjusted for your bore/barrel below.

Barrel Borei

Barrel Lengthi

Cylinder Volumei

Your selected barrel wants roughly 100% cylinder volume for a clean match — mismatches cost FPS/consistency, they never add power.

BB Weighti

Regioni

Classi

Compared against your chrono FPS @ 0.20g below, not the FPS shown for your selected BB weight. These are widely-used defaults, not a universal standard — always confirm your specific site's actual limit.

Rate of Fire Build

Motor and gear choice don't meaningfully change FPS — they control how fast the gearbox cycles. Pick a build goal to auto-fill a matched combo, or set each manually below.

Gear Seti

Motor Typei

Batteryi

—FPS

Muzzle Velocity @ selected BB weight

—

Joules

—

Rounds / Sec

Notes

AEG hardware glossary

Spring (M-rating): Compression spring inside the gearbox that drives the piston. Higher M-number = stiffer spring = more FPS, but more wear on gears, piston, and air-nozzle seal.
Bore size: Inner barrel diameter. Tighter bore (6.01–6.03mm) improves air-seal efficiency and consistency; wider stock bores (6.05–6.08mm) are more forgiving of imperfect BBs.
Gear ratio: Motor revolutions needed per piston stroke. Higher ratio (24:1+) = more torque per stroke = better cold-weather/heavy-spring performance. Lower ratio (13:1) = faster cycling = higher ROF.
DSG (Dual Sector Gear): A sector gear that fires two piston strokes per full gear revolution, roughly doubling effective ROF for a given motor/ratio — requires a DSG-specific gearbox shell.
MOSFET: An electronic switch that routes high current away from the mechanical trigger contacts. Effectively mandatory above 9.6V to prevent arcing damage.
NiMH vs LiPo: LiPo holds voltage steady as it discharges (consistent ROF shot to shot); NiMH sags under load, so ROF slows as the pack drains.
Cylinder volume: How much compressed air the piston pushes per stroke, shown here as a % of a stock "full-stroke" cylinder (100%). Needs to roughly match the barrel's internal air volume — too low a % starves long barrels of air, too high a % just wastes stroke on short ones.

Spring brand cross-reference

"M-rating" is the informal industry shorthand this calculator uses. Most brands roughly track it, but spring numbering is set by each manufacturer, not a physical standard — treat this as a starting point, not a guarantee, and always chrono after installing.

M-Rating	~FPS @ 0.20g	Guarder SP-series	Systema	SHS	Prometheus / Laylax
M90	290–300	SP90 (~295)	M90 (~290–300)	—	MS90SP (~315)
M100	330–350	SP100 (~330)	M100 (~340–360)	—	MS100SP / PSS10 100SP (~340)
M110	350–380	SP110 (~360)	—	M110 (~350–380)	MS110SP (~390)
M120	380–410	SP120 (~390)	M120 (~395–405)	M120 (~380–420)	MS120SP (~410–440)
M130	410–440	SP130 (~430)	M130 (~420–430)	M130 (~430)	—
M140	440–470	SP140 (~460)	M140 (~450–460)	M140 (~450)	—
M150	470–500	SP150 (~490)	M150 (~470–490)	M150 (~480)	—
M160*	~500–520	SP160 (~520)*	—	—	—

FPS figures are for 0.20g BB in an otherwise-stock gearbox — your actual number depends on bore, barrel length, air-seal quality and cylinder match (use the calculator above for that). *M160/SP160 extrapolated beyond commonly published data — confirm with the manufacturer's own spec sheet before buying. Blanks mean no reliably published reference point was found for that brand/rating, not that the part doesn't exist.

Platform & Gas

Platformi

Gas Typei

Barrel Borei

BB Weight

Ambient Temperature: 68°F

20°F60°F100°F

Gas pressure — and therefore FPS — drops in the cold. Propane-based gases (green/red) are far more temperature-sensitive than CO2.

Blowback enabled (unchecking simulates blowback-off / non-BB, sending more energy to the BB)

Platform has adjustable NPAS (uncheck for fixed-valve GBBs — plenty of stock pistols and older GBBRs don't have one)

NPAS Adjustment: 0%i

-15%Stock+15%

Regioni

Classi

—FPS

Muzzle Velocity @ selected BB weight

—

Joules

—

Est. PSI

Notes

GBB hardware glossary

Green gas: ~90% propane / 8–10% butane, usually pre-lubricated. ~115 PSI at 68°F for a generic/Western-market can. The all-round standard gas.
Puff Dino (12kg / 14kg): A Taiwan-made green gas brand very common in PH shops. "12kg" (Standard/Easy Carry) and "14kg" (Power Up) refer to the maker's pressure-tier naming, not a literal PSI reading — both run meaningfully hotter than generic Western green gas, with 14kg rated ~10% stronger than 12kg and better suited to cold weather.
Red / black gas: Higher-pressure propane blend for more power and better cold-weather performance. Verify your GBB's valve/seals are rated for it before use.
CO2: ~850–900 PSI raw, regulated down at the valve. Far less affected by cold, very consistent shot-to-shot, but hits noticeably harder — many fields restrict CO2 on full-auto GBBRs.
NPAS: Negative Pressure Air System / nozzle air volume adjuster. A valve that lets you tune how much gas reaches the striker per shot, adjusting FPS without swapping gas types.
Blowback: The slide/bolt cycling on each shot for realism and recoil. Diverts some gas energy away from the BB — locking the slide (or a non-BB gun) sends more energy downrange.
Barrel bore (GBB): Same principle as AEGs — tighter bore improves air-seal efficiency. 6.01mm suits close-range pistol builds; long-range GBBR/sniper builds usually do better with the more forgiving 6.03mm.

Power Source

Joules Input

BB Weight

Hop-Up

Pick a build goal for a matched hop-up setup, or set each manually.

Bucking Hardnessi

Nub Typei

Barrel Length

—meters

Estimated Effective Range

—

Feet

—

Yards

Notes

These are estimates, not guarantees. Real-world FPS, ROF, and range depend on air-seal quality, BB roundness/weight consistency, hop-up tuning skill, ambient humidity/wind, and individual part tolerances — this tool uses published reference curves and common build heuristics, not a measurement of your specific gun. Field limits are checked against FPS at 0.20g, the standard chrono weight in all three regions offered. Philippines (CQB 420 / Standard 450 / DMR 500 / BASR 550) follows common conventions at sites like The Nest Alpadi Estate. International (CQB 350 / Standard 400 / DMR 450 / BASR 500) approximates typical US/EU outdoor field caps — actual EU sites often regulate in joules rather than FPS and vary by country. Japan uses the ASGK's legal limit of 0.98 joules (~325 FPS @ 0.20g), applied uniformly with no class tiers. None of these are universal — every site and country sets its own rules and some differ meaningfully from these defaults. Always confirm your specific site's actual limit and chrono on-site before a game; this calculator is the final word on nothing.