I'm sitting on a few.
Sportsmans Guide...I've made about 5 orders with them. The first went backorder and I cancelled, the rest have all been delivered in a reasonable time.
Just after the panic started I looked around for normally priced pieces. I ordered, the upper and build kit from Palmetto State, which came in as scheduled. I ordered a lower which came in as scheduled, and I ordered a BCG from Sportsmans guide. Everything came in as scheduled, except the BCG. I got a notice that they would be backordered until March. No problem. Then in March I got a notice that they were backordered until May. OK, still not a real problem. Then in April I got a notice that they were backordered until August...WTF.
Alexander Arms. I decided to prep my rifles for suppressors, and searched and searched for someone with the 51T mounts. I ordered them from Alexander Arms, they didn't list the ones I actually wanted in .308(Brake), but they did list the flash hiders, and I mistakenly took the fact that they didn't list Brakes, but did list Flash hiders as an indicator that they stocked these items. I was apparently wrong, I have received nothing but an order confirmation, in February.
Who else is sitting on Backorders?