Current lore is that 0.32 in an AEG am best0r
Other Angry techs say its 0.28's
Today someone swore to me that he has consistently out ranged others with 0.25s
its a system that can get rather complicated.
from a purely physics perspective (ie ignoring the gun), a bb with X energy, given the correct amount of backspin for its weight, will go further the heavier it is, which is what the spreadsheet
@SSPKali linked to is all about. there's a site online which i forget the name of goes much
much much further down the rabbit hole.
however that isn't strictly the whole argument if you apply it to an aeg and there are scenarios where other factors start to drift in. the crucial thing is assuming that the energy is constant and backspin is magically acheived without affecting energy.
the first issue is the amount of backspin, the energy, and how this is linked. to take a simplistic example lets say a gun can spin a 0.2g correctly and fires a perfect 1J with the hop set to 25% on.
we swap out to 0.25g we need to set the hop to 35% on, the extra resistance from the hop nub being further in drops the energy to 0.8j
then we try 0.3g, with the hop set to 60% on, the energy then drops to 0.6j
try it with 0.4g and there's so much resistance it won't even fire.
how much the energy drops in order to spin a given ammo weight is dependent on hop design, hence why the likes of maple leaf rubbers, s hops, r hops etc are a thing, they're trying to give the bb more spin whilst taking less energy to do so, usually through a larger but longer contact patch, softer grippier compounds etc. what's fun is i've even seen dual "sweet spots", where if you start from zero and dial in the hop you'll meet that point of perfect hop, but keep going and you can do it a second time where the over-hop and energy drop converge again to lift the round properly, of course the lower energy results in much lower range.
the next hurdle is volume, a heavier bb is going to spend longer in the barrel and have higher back pressure, so every source of air leak (including the gap around the bb in the barrel) is going to leak more air, kinda like the reverse of joule creep (where more time spent in the barrel means picking up more energy in systems that are pressure fed and not volume limited). this is dependent on a lot of factors but assuming "perfect" air seal both having a longer barrel or wider bore will add to this issue whereas a shorter barrel and tighter bore will do the reverse. this is more relevant for dmr platforms where folk both have long barrels and want to use heavy ammo in a system with a fixed maximum volume (and hence why you tend not to short-stroke dmr length guns).
so a gun that's built properly (by design or chance) to lob 0.25's may well be worse if you move to 0.3's, but that doesn't mean a gun built properly to lob 0.4's isn't going to be better.
and that's before we start talking about the difference between absolute range (ie how far the bb is capable of going) and effective range (ie how far you can aim, fire and hit a target). when it comes to the latter even things like optics, the size/weight of the gun, trigger response, and skill of the shooter start playing serious factors. for example i stopped running the super heavies in pistols not because the range was any better on the lighter ammo but because it was still better than my capability to shoot with a handgun and you weren't changing bulged nozzles every other magazine. same as how it's pointless running heavy ammo in cqb because accuracy/range is not the deciding factor for getting hits.
On a level playing field of AEG’s+FPS it’s the hop/nub/inner barrel that’ll define your range and accuracy NOT the BB weight .
problem is that's focusing on only part of the system, bb weight absolutely is a factor alongside airseal (read: fps consistency), volume and energy.
to take an automotive example, you could fit the engine from an f1 car in a vw golf and put lewis hamilton behind the wheel, but he won't be winning the championship, hell even if you put a more powerful engine in he still won't win because the rest of the system isn't good enough to take advantage of the strongest element.
Same as my stock TM 416 recoil doing barely 240’ish with .3’s will happily send them out as far as if not further than a lot of ‘stock’ snipers simply due to the legendary TM hop
not just the hop. tm's "magic" isn't just one thing being excellent (as much as we like to joke about the tm hop fairies), it's everything being a good match for everything else in a world where one part not properly fitting another is the norm.
permitting myself a little "luke" moment; tm's are very well put together
for the energy they do but it is somewhat curious how whilst the ~0.8j of a tm is commonly reported to outrange everything, many recoil owners feel the need to crack open their pews and fill them with the contents of the prometheus catalogue, likewise the mighty mk23 with its legendary range gets the maple leaf+hadron treatment, the vsr gets filled with PDI, the MWS gets filled with whatever the hell mws people fill their guns with etc.
) BUT it’ll still send them silly ranges and still has excellent accuracy at the end . 
) but going by the context of it meaning something like "practical battle range" i'd say it's very personal in terms of what a given person is happy with.
