450Bushmaster.net

Hard to say no to some of the deals in my inbox.
I know the QC is suspect with these "low rent" sellers ; BUT the sum of the parts- AeroXL upper , nice handguard and muzzle brake alone are worth the price .
Maybe this one will function with out drilling the port or swapping the barrel...

Some of the budget barrels actually turn out to be good shooters. You might have to play with them a bit to get them running though. With that said, the 450B seems to be a pretty forgiving cartridge.