If that is the place in Washington State, then I have done business with them. Never any problems, but this was likely more then five or six years ago. If it is the same company, they have proprietary lines of products, especially in AR-platform components. I could be wrong, but I think they started as a rifle barrel business. Or I might be confusing then with "Rainer Arms".
Guessing he's referring to "raniersec" AKA "Ranier Gun Store" supposedly located in LosAnchorage, rather than Rainier Arms LLC in Washington (?). There are many cautionary comments online regarding raniersec being a scam. The brick and mortar address they list appears to be fraudulent...
As iofthetaiga mentioned- you might want to check the internet comments including a you tube where they discuss the company using a photo of another reputable gun shop for the internet photo (cropping out the correct name). There are lot’s of very reputable companies doing business online, so unless you please choose carefully. Best of luck with your search and purchases.
Not sure of which Ranier I tried to do some shopping with. You might check how they take "payment" for your "large purchase". They said they had some S&W mags for the Wife's EZ9 that I can't find any where at a great price...until I got to check out. They claim they only take gift cards to get around taxes...so either a tax cheat or a scam?? I put my wallet away.