For more recent versions of Factorio, use this mod for the same results.

This is an updated version of Upgrade by FlamingFox911.
Nothing changed, just modified to be compatible with Factorio 0.16.
Original mod can be found here.

Original description

Are you tired of having useless burner mining drills and furnaces lying around? Ever wanted to repurpose them? Now you can with Upgrade!

A simple little script mod that adds recipes to create more advanced entities using precursor technology entities, similar to how inserters and assembling machines work. This mod can be used on loaded saves as well.

Latest change:
v2.4.0: Added Gun Upgrades. Pistol -> Submachine gun & Shotgun -> Combat Shotgun.