I'm not sure if we got a dodgy batch or the BBs just didn't like our guns, but we had some awful issues with the 0.28s we bought for the NAE weekend. Out of all of the AEGs we brought with us they only fed in one gun. Admittedly in the one gun they worked in, they worked really well. But every other gun they either jammed in the barrel or wouldn't feed in the mags. We ended up having to buy some of the Z1 Blitz BBs they had on site which fixed all the problems we were having. Heck.
They worked fine in:
ASG GBB MP9 (actually worked amazing in this. Got some ridiculous range out of it)
Multiple TM & WE GBB pistols (stock and tightbore barrels)
Cyma shotguns
G&G MP5 (6.03 barrel. Prometheus purple bucking, stock hop unit. Another one that performed amazingly with the BBs, like a laser gun)
They didn't work in:
Specna Arms HK416 (6.03 barrel & standard hop, guarder clear silcone bucking)
G&G CM16 (6.01 barrel & prowin hop, maple leaf 50° bucking)
Specna Arms M4 (6.03 Barrel & MAXX CNC hope with maple leaf 50° bucking)
ICS L85 (stock)
All using PTS syndicate genuine midcap mags and all working fine previously on ASG blaster devils and Z1 Blitz BBs. It seems that they just don't like AEGs that have finer tolerance than stock parts/barrels
i had similar problems with Rockets brand BBs and my old G&P M4 with prowin hop where the jam it caused was so bad it broke the piston, thankfully these weren't so bad. And judging by the countless good reviews no doubt we just had some bad luck and fussy guns. We saw your stand at the NAE but didn't have the chance to come chat about it in person I'm afraid!