Mold fabrication

stankemp

When making a mold (single cavity) for a hollow base bullet is there an optimum angle for the base core so the bullet will fall out? In addition , does the parting line need to be at the start of the ogive?
Thanks in advance, Stan

iceracerx

If you look at a Minie' Ball mold, you will see that most have an Angled or Chamfered "Plug" for the hollow. Most pattern shops require at least a 5 degree taper or "Draft" to assure that parts come out of the mold although in this application 3 degrees might work. If you wish to have an Ogive shaped Plug, then I suggest you place your parting line no deeper than the start of the Ogive, otherwise, you will lock the plug to the Bullet.

Don't forget to create Vents in you mold or you will have problems with Porosity

stankemp

Thank you for the input.
This bullet will be unique (maybe) . I need the hollow base to fill a gas check role.
I'll let everyone know how it works, in a few months, success or failure!
Stan

browser900

A gas check is used on lead bullets to increase the velocity of said bullet up to 2000 ft/sec or there abouts. A flat bassed lead bullet without a gas check can be pusher to about 1300 ft/ sec, + or -. A hollow base bullet can not be used to replace a gas check if one is going to shoot above 1300 feet/sec, + or -. I am at a loss as to how a hollow base will fill a gas check role.