.56 Caliber Colt Revolving Rifle Bullet

[John M. Brooke]

What is the reason for the dimple in the base of some .56 caliber colt revolving rifle bullets?

[joevann]

Swaged rather than cast?

[Jim T]

The "dimple" is from a punch in a bullet machine where a lead slug was forced into the die.

"Swaging" is actually a seperate sizing process and the term was unfortunately misused by M&M.

[joevann]

In ammunition manufacture, swaged bullets are bullets manufactured by swaging room temperature metals into a die to form it into the shape of a bullet.  See "Rifle Ammunition" by Arthur B. Hawes, London: W.O. Mitchell, 39 Charing Cross, 1859.

[Jim T]

...and where in Hawes is the term "swaged" used?  Ref. please.

[joevann]

It doesn't.  The first sentence is the dictionary definition of 'swaging'  which is the cold forming of any material to the shape of a die using pressure.  The Hawes reference was to give the original poster an example of how the bullet making machine works and why the swaged bullets have a dimple while the cast ones have a sprue.  If you are saying that M&M were wrong because you think the process of swaging only refers to apllying pressure to cast bullets or passing them through a die for uniformity of diameter, your definition is much too narrow. Any die used to cold form marerial is a swage, or archaic 'swedge'.   Corbin currently makes machinery for cold forming bullets and they are definately called swages.

[John M. Brooke]

Thanks for the info on the bullets guys. How rare is the dimple bullet?
Out of all those in the bottom picture I only found seven with the dimple.

[joevann]

I don't know.

[PIA]

There are no fewer than four varients of .56 Colt Revolving Rifle projectiles.  Don't know if any one of those varients is any rarer than another.