I am glad your experience was a positive one, mine was not.
I ordered it online and over night received a e-mail stating I needed to get my FFL to send there info in. Since this was my first can, i called the manufacture to see if the tri lug was a restricted part like a registered receiver. They stated it was not. I called Impact Guns and spoke to a CS rep. I advised her the part I ordered was not restricted and did not need to go to a FFL. She stated someone coded the item on the back end wrong and all items in the NFA section were tagged for the FFL e-mail. I asked if I needed to do anything else and was told no. I waited a few days and called back. I spoke to a different CS rep and was told they were waiting on me to send them an e-mail stating I understood the NFA laws. I told the rep i was not told to do this when i called a few days before. I sent the e-mail and waited a few more days, no shipping notice. I called back and spoke to yet another CS rep. She stated she was not sure why I was told to send the e-mail since the item I was buying did not warrant that. I was then told that the part was not in stock and that the warehouse did not send all of the adapter they requested. I asked for a manager and she looked up my situation. I was told by the manager that they put in for X number of tri lug adapters but, the warehouse did not send the full order. I politely told her that was BS since I ordered the part 1.5 to 2 weeks prior and was jerked around with the FFL e-mail, the understanding NFA laws e-mail etc.... She offered to refund the shipping costs, which she did promptly. It took about another month before the part came back in stock.
I did some research before using them and decided to try since most of the complaints I had seen revolved around handgun purchases and not accessories. With all the issues I had, i don't know that would use them again. I know if I needed something fast, they would not be considered.