Are grease gooves necessary?

[rayg]

Just curious, but In reading info about the Lee tumble lube, it refers that the outside dia of the bullet is more important to be lubed then the grooves. If this is so, are the lube groves ready necessary? Ray

[longbow]

There are grooveless boolit moulds. Some have success with them and some do not.

I think if you check the Black Powder cartridge forum you will find some posts.

I have made and used grooveless boolit moulds with good success in some cases though I have used grease cookie lubrication for them in smokeless loads.

joeb33050's book "CAST BULLETS FOR BEGINNER AND EXPERT" has a section on grooveless moulds:

here http://sports.groups.yahoo.com/group/CB-BOOK/

In my experience generally low pressure and low to moderate velocities will most likely be successful.

Some handgun bullets are knurled and lubed with a coating like LLA (as are .22 rimfire) and the knurling is nowhere near as deep as cast lube grooves.

What is youe application?

Longbow

[kir_kenix]

Lube grooves also give a place for all the displaced materal to "flow" to when the boolit is squeezed thru the bore. With out these grooves, I believe the base of the boolit would become disformed, and this would not be good for accuracy.

I'm not sure that grooves would be necessary in low pressure handgun rounds, or most black powder (there are alot of grooveless bp molds out there) where there is not alot of pressure and choice of lube is not as demanding.

Finally, my thinking has always been: if lube grooves are unessary and obviously more expensive to produce, some mold maker at some point would have dropped them for the cost cutting benefit and the rest would have followed in suit.