Investigation of the Influence of the magnetic core on efficiency of multistage gauss gun has been added to FEMM calculation section.

New note "Determination of the characteristic speed of coilgun, or how to build high-efficiency electromagnetic accelerator" is added to theoretical section.

A simple method of assessment of moment of maximum current for overdamped circuits is added to Simple equations for coilgun section.

New Simple equations for coilgun section was added. It will collect relations which allow fast assessment of desired parameters of coilgun. 

A box for vertical gravitational feed of EM-4 coilgun has been assembled. 

The projectile's heads are milled, too. Their diameter is 5,5 mm, the rear parts are thinner and have 0,15 mm cuts to glue tubular stabilizers later.

A sketch of EM-4 coilgun is performed with main dimensions. Laser-cut plywood is planned to be used as material of the case. A wooden detail of rather complicated form will be milled to make the bed.

I am intended to mount a collimator scope (like one used in EM-3 coilgun) on top, but didn't choose its type yet, so it is not presented on the sketch.

New short video of testing of infrared sensors was added to EM-4 coilgun page. Small nail is falling down through the sequence of accelerating stages activating the SCRs (yellow LEDs are illustrating that process).

PCBs for accelerating part of EM-4 coilgun have been mounted.

Merry Christmas and Happy New Year!

PCBs for the accelerating part of EM-4 arrived. Ready to mount.