35 to 50

That "35 to 50" is part of the risk advisory and other literature. Not surprising you hear it over and over.

"Each participant must be able to carry a 35- to 50-pound pack while hiking 5 to 12 miles per day in an isolated mountain wilderness ranging from 6,500 to 12,500 feet in elevation." (2013 Council and Unit Planning Guide)

No way I would let anyone carry 50 lbs on a trek (except my son – he's crazy and super fit). He's also done 6 treks, so he knows what he can do.

I have no experience with the Arc Blast. I'd try it out on some shakedown trips and see how it works out. That's really the only way to find out. If it fits well and works out, you've saved some weight.

BTW,that's him with the umbrella hat next to me in my avatar.

There are many there for which 50 lbs is real. I watched quite a few weigh in 50-60 lb packs.

Id say 45 is the norm.

Our heaviest leaving base was about 35. We were the lightest crew I saw while there. My son and I were the only anywhere near-UL range that I saw.

Mine weighed low 20s leaving base.

I used a Circuit, ~8lb baseweight, and ~4 lbs of crew gear. My heaviest was about 32 into a dry camp with 6.5L water.

Depending on your gear, the arc blast may or may not be big enough. I have read others using them. Dont expect it to carry a heavy water load well though.

I was repeatedly told my pack was too small, couldnt hold the food, etc. Even when I pulled out a zpacks blast foodbag with 5 days of actual Philmont food for show-n-tell, another advisor that had been 4 times, and was proud of his 55 lb 80L pack,and high leather boots, told me it was only about one days food volume.