BLS BIO UH Airsoft BB Pellets 0.40g, 2500 BBs (Bag) – White

BLS PRECISION BIO Ultimate Heavy (UH) airsoft BBs

This expert product description was prepared by the ANAREUS.cz expert team. All rights to this unique content are tied to the anareus.cz domain.Choosing high-quality BBs has just as much impact on the accuracy and performance of an airsoft gun as a precision inner barrel or a correctly adjusted hop-up. BLS PRECISION BIO UH BBs are a proven choice on the market for high-quality 6 mm ammunition. This Taiwanese company offers high-quality and globally best-selling BBs for all types of airsoft guns, whether they are airsoft pistols, rifles, SMGs, machine guns or sniper rifles. BLS PRECISION BIO BBs undergo manual measurement and extremely strict quality control. In addition to dimensional consistency, the manufacturer also focuses on surface quality, carefully controlling the polishing process and smoothness of each BB to achieve maximum range and a consistent flight path. BLS BBs offer an excellent price-to-quality ratio. The measured BB diameter is 5.95 mm (± 0.01 mm), so they can be safely used even in tight-bore sniper rifle inner barrels with an internal diameter of 6.01 mm or in high-RoF setups firing 25+ BBs/s. The pure white colour also makes it easier to track the flight path and fine-tune the hop-up setting. The PRECISION BIO version is made from a special PLA-based polymer (Polylactic Acid), which decomposes in nature many times faster; some airsoft fields and arenas only permit the use of BIO BBs.

How to choose the correct BB weight?

The correct airsoft BB weight depends primarily on the gun's performance, the quality and adjustment of the hop-up system and the intended use. Lighter BBs are suitable for lower-powered guns and shorter distances, while heavier BBs generally maintain better stability when shooting at longer ranges. The table provides an approximate recommendation for BB weight and hop-up bucking hardness, while also showing the muzzle energy in Joules of each BB weight at muzzle velocities of 90, 110 and 130 m/s.

The listed BB weight and hop-up bucking hardness ranges are approximate. The ideal combination also depends on inner barrel length, hop-up unit design, pressure system, the specific bucking, cylinder volume, temperature and the overall tuning of the gun.

How to read the table: The “Approx. gun performance” column uses the standard comparison of muzzle velocity measured with a 0.20 g BB. In contrast, the values at 90, 110 and 130 m/s show the actual energy of the specified BB weight at that velocity. For example, a 0.32 g BB travelling at 110 m/s has approximately 1.94 J.

Key features of BLS PRECISION BIO UH BBs

Technical specifications

• Manufacturer: BLS
• Product line: PRECISION BIO Ultimate Heavy (UH)
• Diameter: 5.95 mm ± 0.01 mm
• Material: BIO PLA
• BIO version: Yes
• TRACER version: No
• Colour: White
• Package weight: 1 kg
• Weight per BB: 0.40 g
• Approx. quantity per package: 2500 BBs
• Packaging: Resealable bag
• Suitable for: AEG, HPA, GBB, GNB and manual airsoft guns

Package contents

• 1× BLS PRECISION BIO UH 0.40 g airsoft BBs (2500 BBs)

Recommendations for using and storing BBs

• Keep BBs clean. Do not return BBs that have fallen into sand, soil or another dirty environment to the magazine. Dirt can enter the hop-up unit and inner barrel.
• Do not reuse fired BBs. After impact, they may have surface or dimensional damage that is not visible to the naked eye and could cause problems when fired again.
• Keep magazines and speedloaders clean. Even high-quality BBs can pick up dust and dirt from a dirty magazine or speedloader.
• The inner barrel and contact surface of the hop-up bucking must remain clean and dry. Oil or grease in these areas can negatively affect BB spin and shot consistency.
• Store ammunition in its sealed original packaging in a dry place away from direct sunlight and significant temperature fluctuations. Reseal the bag after use.

Frequently asked questions from our store

Are heavier or lighter BBs better?

A heavier BB does not automatically mean better performance. It depends primarily on the gun's muzzle velocity, the hop-up pressure system and the bucking (hardness and contact patch design). If your gun has sufficient power and the hop-up unit can apply enough spin to heavier BBs, you will gain a more stable trajectory, better resistance to wind and greater accuracy at longer distances. For lower-powered guns or basic hop-up buckings, choose lighter ammunition so the BB does not lose too much range, as standard plastic hop-up arms may not maintain sufficient pressure for heavier ammunition.

How do I choose the correct BB weight for my gun?

Choosing the ideal BB weight is a matter of finding the perfect balance between a flat trajectory and maximum range. As a general rule, choose the heaviest ammunition that your hop-up unit can still spin effectively without the BB losing too much velocity. If the BB rises uncontrollably after leaving the barrel (“floats”) and reacts strongly to every gust of wind, it is too light. If, on the other hand, it drops towards the ground even with the hop-up fully adjusted, the gun does not have sufficient performance or the hop-up cannot generate enough spin for that weight. A properly matched BB maintains a stable flight path and consistent grouping.

Does the environment I play in matter when choosing BB weight?

Definitely. Field conditions play an important role. Heavier BBs are better suited to outdoor games because they maintain their flight path more effectively, are less affected by wind and can pass through light vegetation more consistently. In CQB arenas and when shooting at distances of 15–25 metres, however, you will not fully utilise the potential of the hop-up system, so lighter BBs can be a better choice. Their higher velocity gives them a shorter flight time to the target and, at the same velocity, their lower energy can also help reduce unnecessarily painful hits on opponents at close range.

What are the advantages of BIO BBs and are they worth buying?

The main advantage of BIO BBs is their reduced environmental impact. They are made from biodegradable materials, most commonly PLA-based plastic derived from renewable plant sources, so they gradually decompose in the environment through the effects of moisture, UV radiation and microorganisms instead of leaving conventional plastic waste behind. Today's premium BIO BBs, such as BLS BIO, also achieve the same dimensional precision, smooth surface and flight characteristics as standard plastic BBs. You therefore do not have to worry about jamming in precision inner barrels or poorer grouping. In addition, many outdoor airsoft fields and events now require the use of BIO ammunition.