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Bite The Bullet

Myth Busters: Do Heavier BBs Increase Accuracy? (2009-04-24)

In previous Bite the Bullet articles, we have determined that heavier BBs and longer barrels do indeed increase the velocity of your Airsoft gun. In this Bite the Bullet we will determine whether Heavier BBs Increase Accuracy or is it just a myth!

We will be using the RWC Hurricane M82A1. It uses a Systema Complete Mechabox M170 Magnum Set, a Prometheus 650mm EG Barrel for PSG-1+, and a G&P M3 3.5-10 x 40mm Scope. The RWC Hurricane M82A1 is capable of achieving much over 450fps. The M82 was kept on the level with Airsoft Surgeon's Wheeler Crosshair Alignment Level.

Testing whether or not BB weight affects accuracy is difficult for a couple of reasons:
When you change the BB you may change the quality as well, even though we will be using the same manufacturer they are not exactly the same. Also, it is entirely possible that there's a power level that "favors" a certain weight, as upgraded sniper rifles often shoot light BBs all over the place. Practice has also shown that heavier BBs have a tendency to be more accurate, but in the end it depends on the quality.

To test the theory, we will be using the following Madbull BBs:

  • Match Grade 0.20g
  • Match Grade 0.25g
  • Precision Grade 0.30g
  • Ultra Heavy Grade 0.36g
  • Ultra Heavy Grade 0.43g
  • Each weight of BBs will be shot 10 times each aimed at the bullseye in Force 2 (7-12km/h) South Easterly wind conditions on the roof of the Redwolf office here in Hong Kong; 20th floor, at 23 Degrees Celsius, with a relative humidity of 78%. Ranged at 25m (82ft) and shooting towards a Southerly direction. The Hop-Up was readjusted for each weight group.

    0.20g Match Grade BBs 0.25g Match Grade BBs 0.30g Precision Grade BBs 0.36g Ultra Heavy Grade BBs 0.43g Ultra Heavy Grade BBs

    Although testing conditions were NOT ideal we can determine now that heavier BBs do increase accuracy, though only up to a certain weight. As probably predicted by most of you readers, the 0.20g bbs were blown all over the page by the windy conditions during the shooting. With 0.25g BBs the shots were more closely grouped together, being only slightly heavier than the 0.20g BBs it was still enough to reduce the effect of the wind.

    The 0.30g BBs achieved the best result by far in this test, featuring the tightest grouping between all 5 weights used. Where the 0.36g BBs had next to no grouping at all, the 0.43g BBs had relatively good groupings as well, but by this time, the wind conditions had dropped significantly.

    The reasons as to why the heavier BBs did not do so well could well be attributed to the M16 Type Hop-Up unit used, but as it stands the BB weight with the tightest groupings were the 0.30g BBs.

    There are a few principles why heavier BBs will increase the accuracy in a lab as well as in the field, when everything else is "fixed".

  • It is easier to produce heavy BBs with a smaller relative variation in weight. For example if the manufacturer sets a +- 0.005 gram weight tolerance with all their BBs, this variation isn't as big (percentage-wise) in a 0.3g BB as a 0.2g BB.
  • A heavy BB is more tolerant to slight inconsistencies of the hop-up, silicone residue in the barrel etc. because heavier objects are more difficult to "push around". A light BB would pick up random spins from dirt particles and scratches more easily.
  • Similarly with the above reason, the heavy BB is able to retain the trajectory. A slight gust of wind or going through a leaf in the bushes doesn't throw it off that easily.

    Special thanks to Sauli Luolajan-Mikkola for providing several parts of the text (All rights reserved). And to Daniel Harrison-Smith for some very helpful suggestions!

    Click here to download the target used in all our RedWolf Accuracy tests! Remember to print using A4 paper!