Gel Blaster Spring Guide: Ratings, FPS & How to Choose
The main spring is the single biggest lever on power in an AEG-style gel blaster, which is exactly why a gel blaster spring upgrade is also the easiest way to break something else if you do it in isolation. Here's how spring ratings actually relate to FPS, and what has to change alongside a spring swap.
How spring ratings map to FPS
Springs are usually sold by a rating like M90, M100, M110 and so on. In the gel world you will also see springs sold by wire thickness — 1.2, 1.3, 1.4, 1.5 mm — which roughly maps to M90, M100, M110 and M120. — a relative strength scale, not a literal FPS number. A heavier rating drives the same fixed cylinder volume harder, with more force behind each stroke, which raises the energy behind each gel ball and therefore its FPS — but the actual number you get also depends on your cylinder, barrel length, and how well the rest of the air seal holds up. Two blasters with the same spring rating can shoot noticeably different FPS if one has a tighter air seal than the other.
| Spring change | Typical effect | What to check alongside it |
|---|---|---|
| Lighter spring | Lower FPS, less strain on gears and motor | Feeding may become gentler on gel balls at close range |
| Heavier spring | Higher FPS, more strain on gears, piston and motor | Metal gears, a reinforced piston, and field/venue FPS limits |
What a heavier spring stresses besides FPS
- Gears. More resistance on every stroke means more load on the sector gear's teeth — see our guide on metal gears for gel blaster gearboxes before pairing a strong spring with stock nylon gears.
- The motor. A heavier spring is harder to cock every cycle, which draws more current and generates more heat.
- The piston and spring guide. A stronger spring needs a piston head and guide rated to handle the extra compression without cracking or binding.
Check FPS limits before you buy
Most fields, venues and organised games set a hard FPS cap for player safety, and going over it can get you turned away or banned from a venue outright. Measure your actual FPS with a chronograph after any spring change — don't assume the spring's rating alone tells you where you'll land, since your specific gearbox, barrel and air seal all shift the real number. See our FPS explained guide for how limits are typically set and measured.
A sensible order for a spring upgrade
- Confirm your target FPS against your field's limit first. Buy to that number, not to "as strong as possible."
- Upgrade gears and the piston assembly at the same time if you're stepping up meaningfully, rather than waiting for something to strip.
- Re-shim after the swap. Re-shim after the swap if you changed gears at the same time — the mesh needs re-checking once the box has been open — see our shimming guide.
- Chronograph before your first game, not after a complaint from the field marshal.
Matched springs and supporting internals are listed under gearbox parts.
Frequently Asked Questions
What does a gel blaster spring rating actually mean?
Spring ratings like M90 or M100 are a relative strength scale, not a direct FPS number. A heavier rating drives the same fixed cylinder volume harder — more force behind each stroke — and raises FPS, but the exact FPS you get also depends on your cylinder, barrel length and how well the rest of the air seal holds — so two blasters with the same spring can shoot different numbers.
Do I need new gears if I upgrade my spring?
If you're stepping up meaningfully, yes — plan for it rather than waiting for a stripped gear. A heavier spring puts more resistance on every stroke, which increases load on the sector gear's teeth. Stock nylon gears can handle mild increases but start failing under sustained heavier-spring use.
How do I know what FPS my spring will actually produce?
Measure it with a chronograph after installing, rather than relying on the spring's rating alone. Your specific gearbox, barrel length and air seal all shift the final number, so the same spring rating can produce different FPS in different builds.
Why does my gel blaster feel harder to cycle after a spring upgrade?
A heavier spring resists compression more, which is exactly what raises FPS — but it also means the motor draws more current and works harder every cycle, and the gears see more load. If cycling feels notably slower or the motor sounds strained, check that your motor and gears are rated for the spring you installed.
Related reading
Start with the full guide: Gel Blaster Gearbox Upgrade Guide.