A magazine conversion system mounts within a magazine well of a lower receiver, and includes a front spacer having a wedge-shaped main body with a lower end, and an upper end having a feed ramp extending upwardly therefrom; and a rear spacer having a wedge-shaped main portion with a lower portion and an upper portion having an ejector element extending upwardly therefrom. With the front and rear spacers positioned within the magazine well, at least a portion of the feed ramp and at least part of the ejector element are positioned above the magazine well.