@emmettluzar 

No, you will not be getting a full 300 Mbps. The theoretical maximum channel data transfer rate of Powerline Adapters is derived from HomePlug AV specifications. The actual data transfer rate will vary from network environment variables including distance between adapters, network traffic, noise on electrical wires, building material and construction, quality of electrical installation, and other adverse conditions.

What you can possibly do is to test other outlets to find one that provides the best performance out of all.