I have a friend who has a couple .50 rifles but he's been real busy lately working on roofs and doing cleanouts at new home construction sites.  I'll get ahold of him and see what his schedule is like and get back to you.  I don't presently have a .50 but have about 3,500 various projos for a .50 as it's just a matter of time now until I get one...just have to decide if I want an AR upper .50 or a Serbu BFG Carbine.  I'm also having it chambered for .50 Spotter Tracer instead of .50 BMG as it uses half the powder and has similar ballistics out to 700-800 yards which is plenty for shooting around here.  I'd like to get an 18" barrel Carbine rifle or upper so the S/T chambered rifle would be more pleasant to shoot as well, I plan on carrying my .50 around rather than it just being a bench shooting rifle...although I do love the AR-50 it's just a little too big.