I have a friend that wants me to help him build an AR-15 in 300 BO. He has going through some chemo issues and want the gun to be as lite as possible. He is also looking for a drop in trigger with a break around 3# (single stage???). Money is an issue but he said that he wants this to be as good and a $1,500ish store bought rifle. Looking for suggestions on all parts and I know that there is a bunch of triggers out there and will have a few different ones to pick from . BTW, he is planning on hunting with the gun and has a multi-can on order.