Be very careful about Blackthorne. The company is sketchy. They used to be Vulcan and before that Hesse. Reputation for bad products and worse customer service, hence the constant name changes.
You're right about here reputation and i think i learn the hard way. Few years back I bought a complete 11-1/2" AR-15 upper with bolt and carrier from them on Gunbroker but had to keep it stored at another location while my Form 1 for the SBR was being reviewed. After 6 weeks I received my Form 1 approval and mounted the upper on my lower unit, only to discover that the bolt was so far out of spec that the lugs jammed tightly in the barrel breach and the bolt would not go into battery.
After some delicate prying to extracate the bolt, I tested two other bolts and carriers from my other ARs in the upper and they cycled just fine. The new bolt continued to jam with I attempted to insert it into my other guns. A comparison of the bolt lugs showed that some were irregularly spaced, and had slightly varying thicknesses when compared to my other bolts!
When I contacted them about a swap for a milspec bolt, as they advertised, they merely sent me a copy of their return policy that stated that they do not take anything back after 3 days no matter what!
Silly me! So I got burned. Be aware that if you buy anything from them, be sure you verify that it is milspec within 3 days!
