40mm Bofors Question

[Godwin Hampton]

Rob and Mats,

Handloaders who reload fired cartridges first re-size them by pressing them into special dies. Various companies produce dies for a whole variety of cartridge designs, some long obsolete but requested by reenactors.

The pressure of the charge on firing expands the brass, but it immediately contracts enough to free itself from the chamber for extraction. It might then not fit into another chamber with less wear in it. If re-used without re-sizing, it might even jam in the chamber!

Even blanks, with their lower pressures, still have a large area of brass to work on, so the force is still considerable.

I am positive that the commercial die manufacturers like Lyman do NOT make them in Bofors L 60 size! What can be done is to try and obtain the chamber part of a cut-up L 60 barrel, and turn the cartridge rim recess in a lathe to make it deeper. The cartridge is then forced into the chamber, using a hydraulic press. The press will probably also have to be used to push it out again.

To feed propely automatic weapons need the projectile to guide the front end into the chamber. In fact blanks made for automatic rifles have a cartridge with a neck as long as the complete round, crimped after filling to resemble the bullet.

For the Bofors to feed automatically the cartriges should have a fair amount of sand in front of the charge instead of the sawdust. Roughly the weight of the projectile, and with a fairly powerful charge. Remember, action and reaction are equal and opposite. Check first if this can be done legally! Why use black powder, and not smokeless to avoid the corrosive by-products?