It’s All Important! Airsoft BB Weight [Everything BBs]

When I first got into airsoft, it seemed to me like the BBs I used were the least important part of my gear – I’d rather buy a box of cheap pellets and save $10 that I could use to upgrade my gun. Looking back, that was a mistake. It may seem time-consuming to go shopping for something as simple as round plastic pellets, but with some research and for only a few dollars more than the bargain-basement brands, well-made BBs can help you become a much better airsoft player, providing you with more accuracy and range, and saving your gun from potential damage. BBs seem fairly simple on the outside, but there are several crucial factors, like weight, diameter, and consistency, that affect whether they’ll perform well in your gun.

What Sorts of BBs Can You Buy?

Although the most common sort of pellet is a simple white plastic sphere, about 6mm in diameter, there are an awful lot of varieties of BB available to the discerning airsoft consumer.

glow in the dark bbFor starters, there are pellets available in pretty much any color you could ask for. White BBs are my preference since it allows me to see the path my shots make and react accordingly, almost like a tracer round. That said, there are darker colors like black and olive green, marketed as “sniper BBs”, designed to make it harder for your enemies to see where you’re shooting from. There are also clear and translucent pellets- my advice would be to avoid these because they’re generally made from a harder, more brittle plastic that’s known to easily dent metal and crack windows.

Glow in the dark BBs is another special sort. They charge under bright light and glow as they fly, making them especially fun when playing at night. They’re easy to spot, again like tracer rounds. However, just shining a flashlight on them before you play won’t be enough to make them glow in flight; you’ll have to get a tracer unit (they’re made to look like silencers and contain a light source to “charge” each BB as it’s leaving the barrel) or an internally-lit magazine to ensure they’re glowing at full brightness.

black bbOne recent innovation comes with the rise of biodegradable BBs. Several companies, such as Bioval and Madbull have begun marketing their own lines of biodegradable pellets, and now many airsoft fields, especially outdoor ones, now mandate biodegradable ammunition. In my experience, these pellets are usually of comparable quality to non-biodegradable pellets. They won’t just disintegrate in your hands, as they can take several years out in the elements before they fully decompose, but for best results avoid getting them wet or exposing them to humid conditions before you play.

Lastly, there are special sizes and compositions of pellet available. One particularly notable round is the 8mm BB, developed by Japanese manufacturer Marushin to compete with the 6mm standard BB. There are only a few airsoft guns chambered in 8mm, and the pellets usually have to be ordered from overseas. Other manufacturers have developed airsoft pellets made out of non-plastic materials. Several companies made paint-coated rubber pellets to allow airsofters to better see where they hit their enemies. Unfortunately, these pellets are prone to very poor accuracy, jam often, and leave large amounts of paint residue inside the guns, necessitating frequent cleaning. Lastly, a Canadian company, BB Bastard, made a niche for itself selling hyper-precision rounds made of materials such as a silicate glass or aluminum, advertising them as the “perfect” airsoft sniper ammunition at prices upwards of a dollar a round.

Best BB Weight- How Important Is It?

Generally, when you’re buying BBs, you’ll see them sold by brand, color, and weight, with the weight marked as a fraction of a gram, like “.12g”, or “.2g”. That can make you wonder, how much does the weight of the BB matter anyway? In a word, “very”. If all other factors stay the same, the weight of the BB has the greatest impact on how well your rifle or pistol performs.

Heavier Pellets Can Improve Your Range and Accuracy

airsoft trainingAt first, it might seem as if lighter pellets would always be better- since they weigh less, they’ll leave the barrel at a much higher speed than their heavier counterparts and hit their targets faster. While that’s true, there are other factors to consider. Lightweight pellets leave the barrel quickly, but when they’re flying through the air, they lose a greater percentage of their velocity to friction against the surrounding air. A .2g pellet that leaves the barrel at 400 feet per second (fps) might only be traveling at 320 fps by the time it reaches 200 feet, while a .3g pellet might still be traveling at 370 fps.

What’s more, heavy pellets are generally more accurate; their inertia means they tend to stay on track where a lighter pellet would not. A crosswind that might knock a .12g pellet several feet off course would have a significantly lessened effect on a .3g pellet, meaning at long ranges, especially if sniping, you’ll want to use the heaviest BBs your gun can realistically shoot.

A final advantage of heavy pellets is that when they’re fired, they’ll spend a fraction of a second longer in the barrel. This means a slight degree of improvement in accuracy, but more importantly, it causes phenomena known as “joule creep”. Essentially, because heavier pellets spend longer in the barrel, they gain more energy from the gun than a lighter pellet would, resulting in higher-than-expected velocities.

Lighter Pellets are Cheaper and Generally Better for CQB

Close quarters combatThat said, heavier pellets have their disadvantages too. For one, they’re expensive. Five thousand G&G .33g pellets costs around $28 while the same number of .2g pellets costs only about $19. That’s more than 50% more for the heavy pellets, and if you’re playing games every weekend, that cost can easily add up.

Also, that little extra bit of velocity from lightweight pellets can be worth the drawbacks. Even though light pellets will slow down quickly, at close ranges, an additional 25 fps may feel like it made the difference between a hit and a miss.

Lastly, since they retain their energy longer into their flight, they do a better job of transferring that energy to their target. Unfortunately, for humans, that means extra pain, and that’s why a lot of CQB games ban heavyweights of BB. If you’re planning to get into close quarter combat in your games, you might as well stick with a reputable brand of .2 BBs.

A word of warning- even if they’re incredibly cheap (and they usually are) never buy .12g BBs. Although the lightweight may seem like a plus, .12g just isn’t enough heft to stabilize the pellet in flight, and almost every brand of .12g is poorly manufactured and may damage your gun’s inner workings. The only use for BBs like that is as ammunition for slingshots and grenades.

My Advice

I personally like G&G .25g and .28g pellets for most uses, but just like clubs in golf, every weight of airsoft BB has its uses. I would recommend:

  • .20g BBs for pistols, shotguns, rifles shooting under 350fps, and light machine guns
  • .25g BBs for rifles shooting 350-400fps
  • .30 or .35g BBs for rifles shooting 400-500fps
  • .40 or .43g BBs for rifles shooting above 500fps

Diameter

bb diameterMost BBs may be labeled 6mm, but the actual diameter usually ranges from 5.95-5.98mm. Any larger than that and the BBs would be much more likely to jam, especially in precision 6.01mm inner barrels. One mark of a well-made brand of BB is how precisely the individual pellets match each other, and you can do this with an inexpensive metric caliper. As an example, I’ve got a bag of the G&G .28g BBs I’m fond of, and I’ve grabbed five random pellets to check. The results are:

  • 5.97mm
  • 5.98mm
  • 5.98mm
  • 5.97mm
  • 5.98mm

These pellets hover around the low side of 5.98mm, which is perfect for an airsoft rifle- small enough to keep from jamming, but large enough to fit the barrel and allow just a little air to flow around the BB. The airflow, called an “air cushion”, stabilizes the pellet and prevents it from bouncing around inside the barrel. More expensive pellets will have even less variance and sometimes an even tighter pellet-to-barrel fit, resulting in higher velocities, but be careful; if the fit is too tight, that can eliminate the air cushion and have negative effects on accuracy and range. One way to make sure that your BBs are a good match to your barrel is to remove the barrel from the gun and drop one inside, immediately capping it with your thumb to make the top airtight. It should take the BB between 6-11 seconds to reach the bottom, depending on the length of the barrel.

Composition

plastic bbBBs are usually plastic, that’s for sure, but no two use exactly the same material. For BBs, a better material composition means they’re homogeneous throughout, with no air pockets to destabilize flight, and, as an added safety bonus, they’ll deform rather than shatter on impact.

Over the years, I’ve learned a few helpful tricks to make sure you’re picking well-made pellets. For starters, check all over the BB for seams. These indicate that the BB wasn’t polished before it was sold. If you use pellets with seams in your gun, you’re putting yourself at risk of jamming the firing mechanism or ripping the hop up bucking, neither of which is worth saving a few bucks on pellets. A second test is to take a sample, set it on a hard, durable surface, and gently crush it with a hammer or other steel tool. In general, good pellets are made of a softer plastic like ABS, which will flatten or mushroom out, while pellets of dubious quality will shatter.

A final test is to cut several of your sample BBs down the center. Look for air pockets inside. If you see one, that’s a sign that the weight distribution inside the BB is uneven, meaning the BB’s flight pattern may be unpredictable and inaccurate. If you don’t feel like cutting them open, you can always set them out on a flat surface and mark them each with a dot from a marker. If the pellet always rolls so one side is on the bottom, you know there’s something wrong with it.

Roundness

The more spherical your BBs are, the more consistent and predictable their flight will be. Ideally, every BB would be a perfect 5.98mm sphere with a perfectly smooth, frictionless outer surface. That’s not possible, of course, but there are still ways to check if your BBs are uniform and close to spherical. My personal favorite technique is to find a perfectly flat, smooth surface, such as a pane of glass, and roll sample BBs across it. If they roll straight across without visibly wobbling, they’re close enough to spherical for airsoft purposes!

Surface Polish

target shootingSmoother BBs mean less friction against the surrounding air, and that translates into faster, more consistent flight. The process by which most manufacturers polish BBs is similar to how rocks are polished in a tumbler- they’re poured into large barrels and agitated, as a fine abrasive medium is mixed into smooth out imperfections. However, the exact “recipe” for the polishing is something of a trade secret for most brands, as proper polishing is one of the most important steps in creating an accurate and consistent product.

Unfortunately, it’s usually difficult for you, the consumer, to discern the smoothness of a pellet without a binocular microscope or other magnifiers. The best test for uniformity and smoothness is simply to grab your airsoft gun, set up some targets at 50, 100, and 150 feet, and do some target shooting to compare brands of BBs against one another.

Airsoft BB Weight Final Thoughts

To borrow an analogy from earlier, picking a weight and brand of BB is quite a lot like picking a golf club- every type has its advantages and disadvantages. Fortunately, BBs are also a lot cheaper than golf clubs, which means you have a chance to experiment to find the ones you like. A quick review of some of the ways to gauge how “good” or effective a BB will be for you:

  • Pick the right weight for your purposes
  • Make sure they’re seamless
  • Ensure their diameter doesn’t vary too much
  • Check to see if they can be crushed, or if they shatter
  • Test their “roundness” and weight distribution

In the end, though, the best way to know you have the right BBs is to buy a wide variety of brands and types, to use them in your gun, and to find the ones that work best for you and your style of play. Please take a look at our airsoft gun and rifle reviews or our informative articles on our website.

Footnotes:

Noah Mains is a writer, an airsofter, and most importantly, he’s stuck in the 80s. From Colt SMGs to David Bowie to brick phones, he has an acute appreciation for the greatest decade, and is more than happy to share his enthusiasm for the ALICE gear system (the superior loadout, of course) with anyone who’ll listen.