[Alk8944]

wattjb

You started an interesting thread here, but you didn't indicate what gun you will be using the ammunition in.

If you need an all around bullet for a revolver, then a semi-wadcutter will do as nicely as anything, if the meplat diameter is equal.  If you intend to use the bullet in a lever action rifle, then you should probably look at the LBT styles.  The semi-wadcutter can give feeding problems frequently, but not always.

Since you mention a 240 gr. bullet I am assuming you will be loading for a .44 Mag.  Lee has a nice 300 gr. gas check bullet which looks like a ringer for the LBT WFN.  Since you are just starting to lookat casting this would be a good way to find out if you really want to cast while saving a little money.  This bullet will work well in any style gun and has two crimp grooves for varying the seating depth.  This is a option which was offered by LBT and can be useful.  RCBS and Lyman also make a similar mould, but at about twice the price.

So far as make of mould goes, I have used most all brands including some no longer made.  All threw good bullets so long as the casting technique and alloy were good.

 

[Alk8944]

wattjb

The short answer to your question about a velocity threshold is no.  There are many factors involved in whether or not a gas check is required or beneficial.  Veral Smith discusses this in his book "Jacketed Perfomence With Cast Bullets".  The book is available from his wife.  See Sixgunner.com under announcements.  As I recall Veral believes that plain base bullets are usually OK to around 1100-1200 FPS if the alloy and sizing diameter are compatable with the partcular gun.  He does recommend them for bullets which will be shot in several guns as sizing is usually a compromise.

When in doubt, use them.  They rarely cause problems and cure several.  The real factor is cost and labor.  If you are buying commercial bullets and checks are an option it would probably be a good idea to order with checks.