My original cutoff for this project was 55#, as on the face of things anything less seems subpar.
But, as you noticed, I allowed 3 bows less than 55# into the mix.
Here's my rational.
Weight isn't everything. One must consider bow design, as well.
For example, I'm pretty certain that the 50# Howatt Hunter has better speed/cast than the 63# Bear Polar, because the two designs are so different.
Also, marked weight can be deceptive.
The BP Mach I is marked 50X#. The "X" means that it is at least 1-2 pounds above marked weight. In addition, the Mach I was noted to be a fast bow.
The Howatt Hunter is marked 50#, but I've never owned a Damon Howatt bow that wasn't at least 2 pounds heavier than its marked weight compared to other same-weight bows.
Wings were known to be efficient bows, but at a straight 50#, the Chaparral likely has the least cast of the bunch, so I guess someone could argue that it's marginal.
My first consideration is for the animal, so I would not hunt with something that I did not have faith in.
With all that said, I would not hesitate to hunt moose with a 50# bow, 500+ grain arrow, and sharp 3:1 two-blade broadhead.
The thing that concerns me most is having a bow that I shoot well to make sure my arrow is on point.