Ball lock o ring smaller than pin lock? Doesn't seem right

[Nemanach]

I bought (6) 5g ball lock kegs a few months ago and installed the o-rings from keg connection. They felt a little loose but they work fine.

http://www.brewinternational.com/oring-ball-lock-stem-set-of-2/

I just bought (4) 3g ball lock kegs and installed the rings from the link below. The internet tells me that the ball lock o ring should be smaller than the pin lock so I used the smaller of the post o rings. The smaller o rings are smaller than the original o rings I bought from Brew International above. They work fine if the disconnect is orientated perfectly on the keg but if I put any pressure they leak. What gives?

https://www.amazon.com/gp/product/B0105JJ8L2/?tag=skimlinks_replacement-20

 

[Nemanach]

I measured the larger o rings and they are 7/16 ID and 5/8 OF which according to the McMaster link below that I got from the o ring sticky seems to be correct. So I seem to have gotten a ball lock o ring and some mystery smaller o ring as the pin lock should be bigger.

https://www.mcmaster.com/#9396k24/=a14764