Expander mandrel

Well, we would suggest that you try Forster, as they make oversized mandrels just for such a issue. Also we would like to add, annealing and proper case neck preparation also helps. Add to that, the Forster Ultra Micrometer dies which seat extremely good too. No runout and always to the correct seating depth, with .001" accuracy. Contact Scott at Forster. Real nice guy and he will help you for sure.
 
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.
 
Plowboy

If you are turning necks, you are running a mandrel in the neck as well right? You have to in order to force any imperfection to the outside and then turn it off.

With your set up as you describe, you are basically doing the same thing as we are describing with the addition of turning the neck.

Steve
 
Plowboy

If you are turning necks, you are running a mandrel in the neck as well right? You have to in order to force any imperfection to the outside and then turn it off.

With your set up as you describe, you are basically doing the same thing as we are describing with the addition of turning the neck.

Steve
Yes sir I use the K&M mandrels. I'll size down if needed to insure the mandrel makes good contact and is able to perform its task prior to turning.
 
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So that I don't completely high jack the thread. I have Sinclair and K&M mandrels. I prefer the K&M because they are polished and the internal case stop is nice. I use the Sinclair's every now and then but they are a little tougher and leave some brass residue if you don't lube properly. Can you get mandrels from others at custom diameters to allow more or less billet grip?
 
So that I don't completely high jack the thread. I have Sinclair and K&M mandrels. I prefer the K&M because they are polished and the internal case stop is nice. I use the Sinclair's every now and then but they are a little tougher and leave some brass residue if you don't lube properly. Can you get mandrels from others at custom diameters to allow more or less billet grip?



21st century sells then in .0005" increments
 
Hello everyone!
I need help selecting a good mandrel to be used as a final step before seating the bullet.
In my mind a mandrel has to have very low tolerances less then 1/1000 thou and be honed to have a very smooth surface.
I see the most popular is the Sinclair one but people are complaining about the quality. The carbide one seem to be good but can you polish carbide smooth the surface?
LE Wilson makes one and I just love it from pictures. It looks like it is polished like he is trying to make a mirror out if it. The downside's only half a thou under. Is that enough for a 300 PRC for hunting?
21st century has a good selection for each calibre in half a thou increments, but their website is atrocious can't tell from the pictures if I'm buying apples or mandrels.
What else is out there that if very good quality?
Holland Gunsmithing has the best on the market.
 
Hello everyone!
I need help selecting a good mandrel to be used as a final step before seating the bullet.
In my mind a mandrel has to have very low tolerances less then 1/1000 thou and be honed to have a very smooth surface.
I see the most popular is the Sinclair one but people are complaining about the quality. The carbide one seem to be good but can you polish carbide smooth the surface?
LE Wilson makes one and I just love it from pictures. It looks like it is polished like he is trying to make a mirror out if it. The downside's only half a thou under. Is that enough for a 300 PRC for hunting?
21st century has a good selection for each calibre in half a thou increments, but their website is atrocious can't tell from the pictures if I'm buying apples or mandrels.
What else is out there that if very good quality?
PMA Tool makes good ones. They are tapered on both ends, so you can really feel them. Their carbide expander mandrels are straight. They are very helpful on the phone also.
 
There are a lot of votes for the 21st century and I already have a couple of products from them, very happy with the brand. I think I'll go with them.

...post edit - I turn my necks to a consistent thickness, and I use a custom honed conventional Forster "Benchrest" full length die sized so that my mandrel doesn't have to push neck out more than 1-2 thou. I run the Forster die without the expander spindle. Forster advertises a custom honing service for this purpose that is done at their factory.
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?


Holland Gunsmithing has the best on the market.
I never heard of them, can you elaborate, please?
 
I use the expander mandrel along with the turning mandrel to get the best fit while turning the necks. and bushing dies to set the neck tension or a polished expander ball with the dies so I can change the expander ball diameter to best size the neck, but prefer the bushings so I don't over work the case neck by sizing it down only to draw the expander back through the neck doubling the working of the case neck.

Just the way I prefer to set/size the neck tension.

Any brand of expander mandrels should be fine with the appropriate turning Mandrell, But I bought the Sinclair neck turning kit with everything needed and really like it. It is a slower process than some others but the end results are second to none.

J E CUSTOM

So you don't use an expander mandrel or the expander ball that comes with the fl resizing die with bushing? I have Redding type s dies with the neck bushings. I select a bushing that is.002 under for Neck tension and remove the expander back/decapping pin assembly all together. It's worked well for me. If a case neck gets dented or out of round I'll run it through the expander ball, but if not in just leave it out. I like this topic because I see and hear a lot of people use the expander mandrel and always wondered why.
 
Well, I'm fully vested in the K&M neck turning system. I have had the pleasure of using Sinclair, RCBS, and Hornady. None of them could match the precision of the K&M turning system. Some will agree,, some will disagree. Now, 21st Centry makes a real good precision turning tools also. A buddy of mine uses their system and I have worked with him, turning his case necks. I was impressed with It's precision. I will say this, regardless of what system you buy.. Buy Carbide mandrels, and Carbide cutting heads.You will not be happy with the steel.
As for lube, Emprial sizing wax all the way.
Try it you will love it. It works great for turning and case sizing. A little goes a long way...
Just my experience with this subject and
Neck turning tools.
 
So you don't use an expander mandrel or the expander ball that comes with the fl resizing die with bushing? I have Redding type s dies with the neck bushings. I select a bushing that is.002 under for Neck tension and remove the expander back/decapping pin assembly all together. It's worked well for me. If a case neck gets dented or out of round I'll run it through the expander ball, but if not in just leave it out. I like this topic because I see and hear a lot of people use the expander mandrel and always wondered why.


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
 
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