Expander mandrel

[aushunter1]

Like you, I don't use the expander ball unless I have to because doing that doubles the working of the case neck and causes it to fail much sooner. Also If you use the correct bushing and then pull the expander ball back through it you have defeated the reason for a bushing.

I only use the expander Mandrell to size the case neck for the turning Mandrell. They come as a set and are designed to get the best fit of the turning Mandrell.

As I posted, this is the way that gives me the most consistent bullet grip and improves the SD's.

J E CUSTOM

Might be just me but I have found not using any expander can give you to much tension.

Plus imo not using any sort of expander, results will differ with how much tension you get depending on neck thickness & by brass brand & also with cases that have longer necks as well.

I like to run a set diameter mandrel through the necks for this reason, we each have our own theories & methods I guess.

I also guess this is why some people swear by the collet sizing dies which essentually use mandrel in the die body.

 

[Beluebow]

I have heard several folks mention using an expander prior to seating. What would this result in that couldn't be accomplished without the step? The only positive I can see is a uniform ID when a die would result in a uniform OD. I, like most folks do not utilize the expander ball in my dies. I use quality dies and neck turn all my brass if needed. I prefer to have no more than +/- 0.0005" neck thickness variation around so since I try to get near uniform neck thickness I assume the post sizing ID is fairly uniform.

My other question is wouldn't we result in a very low bullet grip if we seat after the expander? All of mine (K&M) are 0.0005" under the caliber dimension.

I never get tired of this forum, so much knowledge and experience can be gained....thank you all.

With the proper neck clearance OD doesn't matter.....what matters, is what is touching the bullet and how much.

With the correct size expander in conjunction with the right size bushing or full length die you can get just about any amount of neck tension you desire.....within reason.

 

[Frank Kalisz]

I'll call Forster Monday morning. I really like their dies. I had some bad experience with Redding and I don't want to give them my business anymore.
Do you know based on what factors they hone the die?

I would measure the outside neck diameter of one of your typical completed cartridges (with bullet inserted) and subtract 0.004" from that measurement. That's what I asked Forster to size my custom honed neck to.
Specifically for my 308, I found neck outside diameter of typical completed cartridge with bullet inserted to be 0.338" - so I had them hone my die to 0.334".

https://www.forsterproducts.com/pdf/Custom_neck-honing_full-die_form.pdf

 

[IHFarmer07]

I've got a Sinclair mandrel die and mandrels and I switched to a Kenny Porter die and it uses pin gages which are tool steel, easy and cheap to get. Order them on amazon and sharpen on your own on a bench grinder or whatever, then smooth out with a fine sand paper or buff the roughness out. The pin gages can be had in very fine increments, are very precise and can double as a gage to gage for donuts and to check neck tension before you load with primer, powder and bullet.

 

[Frank Kalisz]

I've got a Sinclair mandrel die and mandrels and I switched to a Kenny Porter die and it uses pin gages which are tool steel, easy and cheap to get. Order them on amazon and sharpen on your own on a bench grinder or whatever, then smooth out with a fine sand paper or buff the roughness out. The pin gages can be had in very fine increments, are very precise and can double as a gage to gage for donuts and to check neck tension before you load with primer, powder and bullet.

using pin gauges as mandrel is a great idea. I use cheap pin gauges from amazon all the time to check my holding tension and I agree they are very good quality. I might have considered something like that if I didn't already have a good 21st Century mandrel die

 

[PNWdude67]

Sinclair expander mandrels work well for us.

 

[Bro Dave]

I bought this one recently, but I have not used it yet. It is a bit pricey, but good quality.

Expander Mandrel Set | Axis Precision Worx

Commercial die manufacturers have no set standards for the Expander ball in their dies. Due to the large variations, this makes it necessary to properly size the inside diameter before seating. We recomend removing the expander ball completely from your resizing dies. Your last step before...

www.axisprecisionworx.com

Nelis, That really is a beautiful set. I tried to order but they said it is not available in this country (US).