Fair. I thought they looked closer. I think there's more to throw though than die footprint isn't there? An xp-l is on a smaller footprint than an xm-l but have similar beam characteristics do they not?
An sst-20 is also 3535. As is the xp-g
Throw is determined by the LED die size to the reflector size.
Basically the smaller the LED die size and the larger the reflector the tighter the hot spot, thus the further throw.
Said fancier, the LED die size to the parabolic reflector shape.
LED makers do not publish die size. Usually a hobbyist on budget light forum will post measurements.
SST20 is a 3535 foot print, but has a small die size. That is why it throws further than a 219b, 291c, 519a, 351....those are all 3535 foot print but larger die sizes than SST20.
XP-P is a 3535 and has a smaller die size than an SST20....so when all things equal, an XP-P will throw further than an SST20.
Osram W2.1 (NM1) is the king of LED throwers as the die size is the smallest available. it is a 3030 footprint
Osram W2.2 (PM1) is twice the size of W1, but still quite small. it is a 3030 footprint.
Lumens at some point come into play as 2 lumens from W1 will not go very far. So, maybe a 351 throws further at 1,000 lumens than a 100 lumens W2.1 when all other things equal.
I believe this is the king of throw when paired with the Osram W2.1
Noctigon K1, thrower, LED flashlight
www.noctigon.com