Gel balls curving, flying wild or grouping badly? How to find the cause
Quick Answer: Look at where the misses go before you touch anything. Flyers in all directions usually mean the gel: mixed sizes or under-grown gels. A steady curve to one side means the spin axis is tilted: a dirty, worn or badly seated bucking, not the hop-up dial. Shots rising means too much hop. Shots dropping means too little hop or gels too small to grip. Fix the gel first, then set the hop-up, then check alignment.
My worst accuracy day had flyers going in every direction. It turned out to be two problems at once: I had under-grown the gels, and my hop-up wasnโt dialled in properly. Fixing only one of them would have left me chasing the other. Thatโs the trap with accuracy: several causes look alike, and the usual first fix, clicking the hop-up dial, only fixes one of them.
Read the pattern first
Fire a full mag at a target from a steady rest and look at the shape of the misses. The pattern points at the cause.
Flyers in all directions: start with the gel
One or two shots going wildly off while the rest group well is almost always a single bad gel. A gel thatโs too small lets air past it, picks up uneven spin and goes anywhere. A gel thatโs split or misshapen does the same. If flyers go in every direction, the ammunition varies, not the blaster.
Under-grown gel is the classic cause. That was half of my problem. Under-soaked gels are small and hard, so they rattle down the barrel and the hop-up grips them unevenly. About 3 hours in distilled water was our best soak for SummerCat SV (growing guide).
Mixed sizes cause the rest. Even good gel has a spread. A sorter removes the outliers at both ends. I sort twice for my 7.3mm barrel and keep only 7.20โ7.25mm gels.
Wrong size for the bore. SV gels in a 7.5mm barrel sit loose and fly wide. Standard gels in a 7.3mm barrel jam and burst (SV vs standard).
Rising or dropping: set the hop-up
The hop-up presses the rubber bucking onto the top of the gel, putting backspin on it. Backspin creates lift at right angles to the direction of travel, the same effect that makes a spinning ball curve (NASA explains it here). Backspin lifts the gel and flattens its flight.
Shots climbing or curling up at the end: too much hop. Back it off a click at a time.
Shots dropping early: too little hop, or gels too small for the bucking to grip. Fix the gel size first, then add hop.
How to set it: with sorted gel of your game size, adjust until shots fly flat to your usual range and only just start to rise at the end. Re-check whenever you change gel line or soak time, because the right setting depends on gel size.
That was the other half of my problem. Once the gel was right and the hop-up was set for that gel, the flyers stopped.
A steady curve to one side: check the bucking, not the dial
The hop-up dial only moves the bucking in and out, so it changes how much backspin the gel gets. It canโt change which way the spin points. A gel that curves to the same side every shot is spinning on a tilted axis, so its lift points partly sideways. The usual causes:
Dirty barrel or bucking. Dried gel on one side of the bucking or barrel grips one side of the gel harder. Clean it first: itโs free.
Bucking seated off-centre or worn unevenly. If itโs twisted in the hop-up unit, or worn on one side, it touches the gel off-centre every shot. Reseat or replace it.
Hop-up unit rotated in the body. If cleaning and a fresh bucking donโt fix it, have an approved QLD tech check the alignment.
A wide, even group: consistency, not direction
If most shots spread out evenly rather than one or two flyers, look at anything that changes shot to shot: mixed gel sizes, uneven hydration across the batch, or a poor air seal. A chrono helps here. A big FPS spread with sorted gel points to seals. A spread that tightens when you sort points to the gel.
Take the gel out of the equation
Graded gel, sorted to your bore
SummerCat states its grown size and hardness for every line. Sort it to your window and any pattern thatโs left is the blaster.
๐ฃ Most players fix the wrong half first
Two problems can hide behind one symptom.
When shots go wild, the hop-up dial is the obvious thing to reach for, so it gets clicked first. Sometimes that helps a little, which makes it worse: you think youโre on the right track, and the real cause stays hidden.
In my case the gel was under-grown and the hop-up was off. Adjusting the hop for bad gel set it to the wrong value, because the right setting depends on the gel. Fixing the gel alone left the hop wrong.
So always work in this order: make the gel right and consistent, then set the hop-up for that gel, then check alignment. Each step makes the next one mean something.
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Frequently asked questions
Why do my gel balls curve to one side?
A steady curve means the gel spins on a tilted axis, usually from a dirty, worn or off-centre bucking. The hop-up dial changes the amount of spin, not its direction.
Why does one shot fly way off when the rest group well?
Thatโs a flyer, and itโs usually one bad gel: too small, split or misshapen. Sort your gels and check your soak time.
Why are my shots going everywhere?
Usually under-grown or mixed-size gels, often with a hop-up set for the wrong gel size. Fix the gel first, then reset the hop.
Should I adjust the hop-up for flyers?
No. Fix the gel first. Use the hop-up only for shots that rise or drop.
Can a dirty barrel affect accuracy?
Yes. Dried gel on the barrel or bucking grips the gel unevenly. Clean it before changing anything else.
Sources
- NASA Glenn Research Center - Lift of a Baseball (spin and lift direction)
- RedSpear Armory - SummerCat Pink SV soak-time test, 3 August 2026
- RedSpear SummerCat, GLOW and electric sorter listings: prices, sizes, hardness and bracket windows, checked 1 November 2026
- Patrick Amadeu, RedSpear founder - interview on his own gel, sorting and game-day routine, 1 November 2026
Last checked: 1 November 2026.
Still missing?
An approved QLD tech can check the bucking and hop-up alignment. Replacement buckings and hop-ups turn up in used parts and accessories.
Read next: Do sorters help? ยท Too hard, too soft, bursting ยท Upgrade guide
Written by Patrick Amadeu
Founder of RedSpear Armory and a critical care paramedic since 1989. Iโve played indoor at Blacksite and the former GelSoft Yatala, and outdoor at Donnybrook, Kooralbyn and Bundaberg. RedSpear exists because my first rifleโs gearbox died four days after the shopโs warranty ran out. More about me
RedSpear Armory โ Queensland's dedicated marketplace for used gel blasters. Browse listings, sell your gear, and connect with the local QLD community at redspeararmory.com.au.