I too have found GM barrels to be very good quality. Yes you can find cheaper, but there is a reason for the price difference.
Please note, that there is no caliber markings on the military type barrels ( you are looking for a M16 variation) if that matters to you.
I don't care about the lack of markings, but some folks do.
The cost is a few dollars more than you posted, but in my opinion, if you want to build a shooter, it is worth it.
To simply blast away, with "acceptable" accuracy, there are much less expensive options. If you want good accuracy ( many report less than moa) then a GM is a good choice.
Good luck, and have fun with your build
Rich
