Do buckings become more consistent after break in?

[lurkingknight]

the most basic term that covers bio I believe would be how fast the binder breaks down, leaving the trace styrene and whatever else was used in the composition.

From what I understand all BBs have at least some styrene in the formula. I don't think there's any naturally biodegrading compounds that make up the bulk of what's in a BB, just what holds everything together in that shape.

There's so much snake oil in the airsoft business that I find it hard to believe the claims of any one company. You'd have to be a chemist or a polymer engineer to determine what's left after the binders breakdown in a BB, because the companies aren't going to tell you claiming some proprietary formula that's better than x other brand, even though all the BBs in the world probably only come from a handful of factories, they'll all use similar formulations. You'd have to take their word for it, and almost guaranteed that most if not all those factories are located in china, whose business practices are known to be shady at best.

Whatever they're using, you have to assume that it will be cheap to use as weighted filler. It doesn't make any sense to use expensive filler, regardless of what is claimed. At a guess I would say it's iron filings, but that's just me. We know whatever it is they're putting in is magnetic... at least on WE and madbull.

[BenG]

Tiny amounts of metal are everywhere, I dont feel like a few fractions of a fraction of a gram of metal is going to do anything, even if you and everyone else shoot off 1000 .40g bbs I doubt you would have a noticeable amount of metal contamination. In anycase the people shooting .40g bbs arnt the people shooting 1000s of rounds per day, a few hundred tops. I would be more concerned about the bio bbs actually biodegrading.

[ThunderCactus]

Everything iron and below I think is pretty abundant in nature.
Europe has the strictest testing for what constitutes BIO BBs, and they break down the BBs in a lab and stuff. So if it has Euro certs, you know it's legit.