I wanted to take a moment and post a kudos to Rainier (not that anyone here needs to be told they're great).

I ordered a few small parts to finalize the CMT SPR build. Needed a Rifle buffer and spring, A2 stock screw and rifle gas tube.
Someone how received a rifle buffer tube instead of the buffer itself.

Contacted Rainier, they responded not long after saying they're already shipping out the correct part and sent me a prepaid USPS shipper.

Received the correct part three days later.

Couldn't have made the process any easier.