I have an as new post Dissipator upper and will trade for a post or pre ban upper, prefer bushmaster, Colt, RRA. + or - $ as warranted.
Info on dissipaor:
Introduced in '94 and manufactured only by Bushmaster - this 16' Barrel configuration features full length handguards with aluminum heatshields to dissipate heat quicker than any other model. The front sight is placed so as to obtain the full sight radius designed into the M16A2 sight system. The Dissipator barrel is hard chrome lined in both bore and chamber.