Hey all, I am fairly new to the forum and wanted to pick some of your brains. I am going to start my first AR build very soon. First I am looking to purchase a lower I've been looking at spikes and rock river mainly. Today I was on Aimsurplus.com when I stumbled across the R Guns receiver(as pictured) I was curious if they are of good quality compared to RR or spikes. Also what the difference was between this receiver and all the other stripped lowers. Is it just that it has the ramp, ejection door, and forward assist? Also I am wanting to put together the lower and buy an upper since uppers are more complex to work on. I am new to the AR world so I will have a lot of questions and any advice will be much appreciated!