// GEAR EXPLAINED
Airsoft BBs explained.
BBs are the cheapest thing you buy and one of the easiest to get wrong. The right weight and quality make your gun more accurate and more reliable. Here is what actually matters.
The basics: 6mm, and quality first
Almost all airsoft guns fire 6mm plastic BBs (a small number use 8mm, but 6mm is the standard). Beyond the size, the two things that matter are quality and weight.
Quality comes first because it is the one that breaks guns. Good BBs are seamless, perfectly round and polished to a precise size. Cheap BBs can be uneven, out of round, or have moulding seams, and those flaws jam your feed, chew up the hop-up rubber and barrel, and scatter your shots. Quality BBs cost only a little more and are worth every cent. Never use BBs meant for other things, no metal, gel or paintball rounds, only proper 6mm airsoft BBs.
BB weight, and what it does
BB weight is measured in grams, and it changes how the BB flies:
- Lighter BBs (0.20g to 0.23g): faster off the barrel, but easily pushed around by wind and lose accuracy at range. Fine for close-range and lower-powered guns.
- Mid-weight BBs (0.25g to 0.28g): the sweet spot for most AEGs. More stable, better accuracy, still plenty of range. Many players settle on 0.25g.
- Heavy BBs (0.30g to 0.40g and up): very stable and accurate at distance, less affected by wind, but need enough power and hop-up to carry them. Favoured for DMRs and snipers.
Weight, FPS and hop-up work together
BB weight is not chosen in isolation. It works with your gun's power (FPS) and hop-up. The hop-up puts backspin on the BB to give it lift and extend range, and a heavier BB needs the hop-up adjusted to suit. When weight, power and hop-up are matched, you get a flat, stable flight and consistent accuracy. When they are mismatched, shots curve, drop early or fly erratically. It is worth chrono testing and tuning with the weight you plan to use, see our NZ FPS limits guide for how chrono testing works.
Biodegradable BBs
Bio BBs are made to break down over time instead of littering a field forever. Many outdoor venues require them, and they shoot exactly the same as standard BBs, so there is no downside outdoors. Check your field's rules, but using bio BBs outdoors is simply good practice.
Quick buying tips
- Buy quality, seamless, polished BBs from a known brand.
- Match weight to your gun, around 0.25g is a safe AEG default.
- Use biodegradable BBs outdoors, and check field rules.
- Store BBs sealed and dry, dirt and moisture cause jams.
- Never reuse BBs off the ground, they pick up grit that jams guns.
