Simply put – accessibility. Due to the high amount of competition for online gun part sales, you will find a greater variety of parts, brands, and accessories for the AR-15 at better prices with online shops versus traditional brick & mortar retailers.
The internet has made commerce easier by allowing consumers to access merchants without the barriers of geography and time (outside of shipping). This is especially true when it comes to buying gun parts online. If you live in central or upstate New York then you know there aren’t many gun shops outside of the big cities and those that do exist are usually smaller shops with limited inventory when it comes to parts and accessories for your AR-15.
While there are some shops in NY that carry or even specialize in AR-15 parts, they can only physically carry so many parts or brands on their shelves and they can generally charge much higher prices than online competitors due to the lack of shops to choose from locally. Many online stores also have great refund/exchange policies or lifetime guarantees like Brownell’s. This generally makes purchasing online a much better choice – especially for bargain shoppers.