They are about 12 weeks out but they are now taking orders for barrel/bolt combos. You can have them make them the way you want and there's no additional charge for it. I ended up ordering an 18" with a midlength gas system and it's threaded just like the Bushmaster. They say they almost always use midlength gas systems so I went with their recommendation, I'm a little nervous about that. They take your payment info but do not charge your card til they are ready to ship. They are a stainless bead blast/brushed stainless look. I hope I made a good decision on this one. I couldn't decide between a 16" and 20" barrel, but since I could decide I went with an 18" because I have a 3 gun rifle in 18" and like the length. We'll see!!
http://ballisticadvantagellc.com/450Bushmaster.php
They say they use match grade barrels.