I was first interested in this company for its side charging models. I don't think they asberate the benefits this offers. They produced at least one video illustrating some of the benefits like easier access when a scope is mounted. I believe they are the only manufacturer to offer this with a reciprocating charging handle giving the shooter control of the bolt. I know have purchased several uppers and three lowers; AR 9, AR10, and AR15. I have not experienced any problems and the fit and finish was excellent.