# Archive for November 29th, 2013

### Browning Hi-Power Magazine: Trigonometry

The Browning Hi-Power magazine case has a 12.5° forward angle with respect to the floor plates:

The natural axes lie parallel and perpendicular to the case axis, which means dimensions parallel and perpendicular to the floor plates (horizontal & vertical, respectively) require a bit of trigonometry. This doodle sketches some of the key values, not all of which are hereby asserted to be correct:

Name the variables:

• Slant angle α
• Height H along magazine axis
• Length L perpendicular to H

Components of H:

• vertical = H cos α
• horizontal = H sin α

Components of L:

• vertical = L sin α
• horizontal = L cos α

Extreme point of the tilt at the edge, relative to center point on axis:

• vertical = (L/2) sin α
• horizontal= (L/2) cos α

Projection of top parallel to axis onto horizontal:

• L / cos α

I suppose one could set up functions for all that, but I tend to just hammer out the trig where it’s needed.