What is the purpose for 1 or 2 cannelures on a bullet?

[mikenbarb]

I have seen that some bullets have two cannelures instead of one. Is there a reason for them to have two of them. Is it for different seating depths? I dont get it.:confused:

[WIL TERRY]

Mostly...

[Loader9]

You'll find that on some bullets for pistol and rifle cartridges. The 44 caliber comes to mind first. Some have the double cannelure for the pistol loads and another cannelure for the 444 Marlin. So you're correct about various seating depths but for different applications using the same bullets.

[DEDON45]

As another poster said, it's to accomodate different seating depths, often with cartridges that are commonly chambered in rifles and pistols... .44Mag, for me, was the first place I saw this, with a Hornady 300 grain XTP (I think Speer's 300 grain is the same way). The manual stated which situation called for seating to which cannelure.

[mikenbarb]

I was wondering because I got some 30 caliber 128gr. armor piercing bullets that have 2 cannelures. Their weird because they have a nickle color to the jackets. I have no idea what their from or for but im gonna load them and shoot em up.;)

[nitesite9]

The Hornady .357 180-gr XTP bullet has two cannelures; the lower one for standard .357 Magnum cases (and pressures) and the upper is for .357 Maximum with the longer cylinder.