mandrel for case necks...can somebody please explain

[Shawn Carverelli]

this is pretty new and I might be a little slow.
I understand the theory of turning necks, neck sizing without full length suze and full length plus using a neck bushing to resize a neck to customize neck tension on a bullet.
However, I hear talk about using a mandrel that pushes into the neck. I don't understand why one would want to do that if you can resize the neck from the outside.
Can somebody walk me through this? I've reloaded my own ammo for 25 years, but this seems odd to me.

 

[sedancowboy]

Shawn
When we pull a expander Ball back through the neck to set the final neck neck diameter we stretch the neck and introduce more runout.
We have learned that a Mandrel pushed into the neck does not stretch the neck and introduces much less runout.
The reason we use a Mandrel to expand the neck instead of relying on the neck bushing is because brass resists the last direction we move it in. Plus the Mandrel pushes the imperfections to the outside of the neck causing more consistent neck tension.

 

[milboltnut]

some say, including John Whidden, of Widden custom dies, that bushing dies create runout, mandrels create less. Some say that runout isn't as important as straight cases in chamber.

Body dies and Lee neck collet die are best to many. I checked runout on the shoulder with my Redding body die. +/-.0005. Lee collet neck die has the same. Another option is honed neck FL dies. Some say they work well runout wise with unturned necks.

 

[sierracharlie338]

Shawn
When we pull a expander Ball back through the neck to set the final neck neck diameter we stretch the neck and introduce more runout.
We have learned that a Mandrel pushed into the neck does not stretch the neck and introduces much less runout.
The reason we use a Mandrel to expand the neck instead of relying on the neck bushing is because brass resists the last direction we move it in. Plus the Mandrel pushes the imperfections to the outside of the neck causing more consistent neck tension.

All summed up right here

 

[milboltnut]

even the Forster elevated ball expander isn't what they say they are, they still induce runout. If you want to experiment, get a concentricity tool gauge. I made one for peanuts. You probably won't take our word for it completely until then. It took a while to get a body die and collet neck die, suggested by others.

 

[FEENIX]

This guy does an excellent job of explaining the different options.

 

[milboltnut]

that guy is too long winded, and has his opinions. I mean don't get me wrong, his information is good but he doesn't come up for air. You're better off reading what some have to say, He basically says what I did about bushings verses mandrels.

 

[Hard rock]

that guy is too long winded, and has his opinions. I mean don't get me wrong, his information is good but he doesn't come up for air. You're better off reading what some have to say, He basically says what I did about bushings verses mandrels.

Since I've gone too bushing dies I've nearly eliminated bullet run out , some are .00 and some at the most is .003 . How much better can you expect from a mandrel . I don't use the expander just neck back down.

 

[milboltnut]

Since I've gone too bushing dies I've nearly eliminated bullet run out , some are .00 and some at the most is .003 . How much better can you expect from a mandrel . I don't use the expander just neck back down.

people look for consistency, and it doesn't appear that you are gettin that. However, one F class guy says he gets .004 and doesn't care. Some care some don't. I was loading seriously wobbly cartridges, until I started using mandrels. Others have mentioned that anything under 5 thousands shouldn't be a concern. Case chamber alignment is. Why not consistently eliminate runout. And the cheapest and easiest way is a quality body die and Lee collet neck die.

 

[Varmint Hunter]

I haven't pulled an expander button/ball up through a case neck in decades. Doing so can definitely create inconsistencies. I have been using bushing dies for quite some time and have had excellent results. Virtually all of my rifles will shoot <.5moa @ 400yds with carefully tailored handloads. I only own "hunting" rifles and the level of accuracy that I'm getting actually exceeds my needs.

Using mandrels might make my ammo a bit more consistent, but I doubt I'd be able to see anything on paper at the distances I shoot. If you're shooting competitively at long range than the use of mandrels may show some on-target improvement but beyond that, I don't see the benefit.

 

[FEENIX]

that guy is too long winded, and has his opinions. I mean don't get me wrong, his information is good but he doesn't come up for air. You're better off reading what some have to say, He basically says what I did about bushings verses mandrels.

You can never satisfy everybody even with the best of intentions.

 

[Hard rock]

You can never satisfy everybody even with the best of intentions.

Are you saying if I go too using mandrels I can completely eliminate bullet run out , I will definitely change too mandrels I have had really good results with bushing dies but man , consistent .000 run out would be the way too go.

 

[FEENIX]

Are you saying if I go too using mandrels I can completely eliminate bullet run out , I will definitely change too mandrels I have had really good results with bushing dies but man , consistent .000 run out would be the way to go.

NO! The guy provided options, what you do with them is entirely up to the end-user. The guy even caveat to stick with what works for you. I am not sure where the confusion is.

 

[Varmint Hunter]

Are you saying if I go too using mandrels I can completely eliminate bullet run out , I will definitely change too mandrels I have had really good results with bushing dies but man , consistent .000 run out would be the way too go.

I believe that the idea behind mandrel use is to not introduce runout. Runout could be caused by many things and the use of a mandrel is not to eliminate runout that's already present.

Or, that's at least my take on it.