Mandrel die/bushing die

[Manns50]

Just getting ready to set up some 223 Lee dies in a Dillon 750. Been loading pistol rounds for years but just now getting into rifle calibers. I’ve been reading about the Redding full length bushing dies I understand the basics but is a mandrel die the same thing as a bushing die? Redding has three different sets of bushing dies that I was looking at, exploring my options.
Any input greatly appreciated.

[country gent]

Used right the bushing dies do away with the expander/mandrel sizing only what the case needs, Saves extra working of the brass. Bushing dies also allow you to experiment with neck tension of the loaded rounds.
I use a mandrel die for rounds I neck turn sizing on the mandrel and the same mandrel is used in the neck turner to achieve the desired fit. After the neck turning it bushing dies to load.
Mandrel/expander dies are notorious for under sizing the neck then opening it back up creating more work on the brass. This compensates for various neck thickness. The bushing die dies this by using diffrent size bushings.

[Taterhead]

If you will use mixed cases (e.g. range pickups), I'd recommend a regular full length sizing die with expander button. I wouldn't mess with bushing dies. Bushing dies are best fir common head stamps with turned necks. Otherwise they make consistently round necks outside, but that means the inside diameter is not of uniform roundness or diameter.

An expander button pulls up through the neck post-sizing to make it uniformly round and of consistent diameter (ignoring differences in brass springback).

[Taterhead]

I will add that shoulder bump is critical in ARs, so I make expeditious use of an LE Wilson gauge for all my AR 15 ammo

[Manns50]

Expander button? I’ll have to look that up unless it’s reference to something I’m already familiar with.

[David2011]

The expander button or ball sizes the inside of the neck of a bottlenecked cartridge after it’s sized, all in one motion. It’s part of the sizing die, on the decapping stem just above the decapping pin. It works as the decapping pin is withdrawn from the cartridge.

[Taterhead]

People call them different things. Here is a common type found on RCBS sizing dies as indicated with a pen. Typically .002" less than nominal bullet diameter. For 223 Rem, I honed mine down to .221" for a touch of extra insurance on neck tension.

https://i.postimg.cc/hGFc1mhd/20190211_205027.jpg

Here is a Redding variant. It is more of a cylinder.

https://i.postimg.cc/W1qsZ8pV/20190211_205031.jpg