Dead Space: Extraction

To achieve a perfect reload you need to press to reload your weapon, then watch the radial dial cross-hair on your screen and when the blue bar is inside the grey area hit again. You should generally get into the habit of doing perfect reloads as it greatly speeds up reload time. I've found the rivet gun to have the easiest perfect reload bar. You also have infinite ammo so you could theoretically "farm" this. When you get to a point in a chapter where you've got to open a door, don't. Instead shoot your rivet gun once then reload. Repeat until you're confident you're up to 80% or above. Best done in the earlier chapters such as 1 or 2.