Is Using Expansion Mandrels or Full Length Sizing Die with Bushings Better

[Timon]

Not a question about FL sizing vs neck sizing, I FL size. Was wondering what the thoughts were about using an expanding mandrel vs bushings to set neck tension. Or do you think it’s just a matter of personal preference? I already had a redding S die with various bushings. Then for Christmas I received a set of expansion mandrels and the die to go with them, as I had talked about them to my son. Now I’m wondering is one really better than the other, since I have both. The expansion mandrels do come in half thousands sizes. Or is this just personal preference. Thanks

 

[newbieshooter]

I don't believe it is "one better than the other". I use both as a complement to each other.

 

[marchboom]

With my two 22-250s runout was .0005" on one and .0008" on another. After using a Redding type S FL bushing die the runout increased to .0035" and .005", respectively. I then ran those cases thru a Forster FL die and it brought the runout down to .0025 and .0035". When I used a Forster FL die on cases right out of the gun and runout increased to approx .001, if that. Neither die had the expander installed.

I tried reversing the bushing and that didn't work. I tried numerous cases to make sure the results were not a fluke. The results were always the same. The Redding FL bushing die induced considerable runout into the case. Needless to say, the Redding die was sent back. I now only use Forster FL dies. I also send them to Forster to have them honed to the size I want that will result in less working of the brass.

I also use mandrels to bring the neck I.D. to the size I want. Using a mandrel moves any imperfections to the outside of the case where it doesn't affect runout of the bullet (not runout of the O.D. of the case).

 

[wkdickinson]

I am not an expert by any means, but what my process has evolved into is, using full-length bushing dies (Redding or Whidden), with the expander button removed. I use mostly Peterson brass, which I find to have a reasonably consistent neck wall thickness, so I don't neck turn. I get a good average of the neck wall thickness and pick a bushing that under sizes the neck by .002"-.003". Then I use a mandrel to finish size the necks to about -.001" under the bullet diameter (single-shot target rifles). I use a Forster COAX press and anneal before each reloading of the brass.

With this process I think my neck tension is much more consistent and the concentricity of my loaded ammo has improved significantly.

 

[caihlen]

I fl size with a Whidden non bushing, with the button removed. Then I use a Sinclair expander. I get great runout and really consistent neck tension.

 

[Timon]

Thanks folks. You all have verified my thoughts. I was going to use the fl bushing die, then follow up with an expansion mandrel. After reading a few posts I have become a little concerned about the Redding bushing die inducing runout. I will have to check it very close.

 

[Timon]

One more question. Are you are allowing for spring back? I use nothing but Lapua brass, which I believe is on the softer side. If you allow for spring back, do you think .001” is proper? Should it be half of that or perhaps a half more?

 

[gdbleb]

From my reading and experience it all depends on how much you reduce the neck OD with your bushing. Somewhere around .005 reduction and the chances of increased runout also increase. It has been suggested that one could reduce the neck OD in 2 steps with an intermediate bushing size. I tried this and it seemed to be effective most (but not all) of the time. More recent writings from some top shooters seem to indicate they don't much care about runout anymore as long as it is modest (~.001 - .003).

 

[Patriot007]

Three years ago Eric Cortina put out a video on this subject. Over the past year I have experimented with this method and have found it to work 100%. It's funny how that Forster FLS die with the top half of the die removed. (expander ball and top assembly) replaced my Redding body die, and my Forster Bushing bump die,( top half removed from it also) and the Lee collect die.. All I do now is Anneal, FLS, and expand with my 21Century expanding mandrel. My over all bullet run out is less than .0005. If you have not tried this method, I suggest that you try it. I know, for me it goes against over 2 decades of reloading where fire formed cases were the best. For me I'm still using both methods until I acquire the other Mandrel kits I need for the rest of my arsenal. But I find that the Expanding method works best and a lot quicker and more consistent.. JM2C

 

[marchboom]

I have a set of pin gauges from .221" to .224" in .0005" increments. I use these as my sizing mandrels but also as gauges to check the "after mandrel sizing" neck I.D. Which size gives me the best groups? That's where you have to do some experimentation. See which size mandrel gives you the best groups. Run the mandrel thru a FL sized case and then use another mandrel (will probably be .0005" to .001" less) to check the finished I.D.

Make sure the inside of the case neck is lubed when running the pin gauge thru it.

 

[Patriot007]

One more question. Are you are allowing for spring back? I use nothing but Lapua brass, which I believe is on the softer side. If you allow for spring back, do you think .001” is proper? Should it be half of that or perhaps a half more?

More like, .0002/.0003 which is about what I'm figuring with my hole and pin gauges (Spring back). That's with annealing after every firing on my Lapua Brass turned to .0135. I found that with my Lapua brass that if I want 2thou neck tension. I have to use my .2625 mandrel. The .2620 mandrel after expanding, springs back closer to, .2615,, tighter than I like. So,, I use the .2625 and with spring back. That gets me closer to the 2thou
neck tension that I'm looking for. Keep in mind, that you have to allow for spring back.

 

[PopCharlie]

I have used Forster non bushing FL sizers with polished expander balls for a couple of years now. I am now using the same dies with the ball removed, and setting the tension with a Porter mandrel die. Im looking for more consistent ES and accuracy. I have never liked the bushing dies, I do have some, and have used them. I usually got pretty bad runout on necks using bushing dies, like .005 or .006. So I switched.

PopCharlie

 

[marchboom]

I have used Forster non bushing FL sizers with polished expander balls for a couple of years now. I am now using the same dies with the ball removed, and setting the tension with a Porter mandrel die. Im looking for more consistent ES and accuracy. I have never liked the bushing dies, I do have some, and have used them. I usually got pretty bad runout on necks using bushing dies, like .005 or .006. So I switched.

PopCharlie

I really wanted to like the Redding type S FL bushing dies but when I saw that they INDUCED a lot of runout I sent the die back. Forster FL dies keep everything in alignment and Forster will hone them to my dimensions if I want to reduce the amount I work the brass during sizing.

 

[Bill Norris]

From my experience, The expander mandrel and then the bushing of choice produces less runout for me.

 

[338 dude]

Not a question about FL sizing vs neck sizing, I FL size. Was wondering what the thoughts were about using an expanding mandrel vs bushings to set neck tension. Or do you think it’s just a matter of personal preference? I already had a redding S die with various bushings. Then for Christmas I received a set of expansion mandrels and the die to go with them, as I had talked about them to my son. Now I’m wondering is one really better than the other, since I have both. The expansion mandrels do come in half thousands sizes. Or is this just personal preference. Thanks

I use both but the mandrel is my final step with my brass preparation

 

[JimSC]

Three years ago Eric Cortina put out a video on this subject. Over the past year I have experimented with this method and have found it to work 100%. It's funny how that Forster FLS die with the top half of the die removed. (expander ball and top assembly) replaced my Redding body die, and my Forster Bushing bump die,( top half removed from it also) and Lee collect die.. All I do now is Anneal, FLS, and expand with my 21Century expanding mandrel. My over all bullet run out is less than .0005. If you have not tried this method, I suggest that you try it. I know, for me it goes against over 2 decades of reloading where fire formed cases were the best. For me I'm still using both methods until I acquire the other Mandrel kits I need for the rest of my arsenal. But I find that the Expanding method works best and a lot quicker and more consistent.. JM2C

I agree, I recently went with the method and love it. Very little if any runout

 

[Fuj]

Full length size only then over to the press with the LEE
mandrel collet die. My ammo is straight.

 

[Ironman308]

I use Redding Bushing dies for my tactical rifles. Recently I bought a concentricity gauge for my new adventures into the 6PPC for Benchrest shooting. When I checked my tactical brass I found 0.007 runout on the 6.5 other calibers were much better. I performed several tests one of which was using a Forester die. At the end of the day I replaced the bushing and was happy with 0.001 to 0.002 of runout. The Forester without the bushing was at 0.001 or less. So, sometimes it’s just a bad bushing. Now I will likely switch to Wilson bushings and see how they perform.

 

[skeeljc]

My Redding FL bushing die produces 0.002" t.i.r. runout on average (no expander).
My Redding FL fixed die produces 0.0005" t.i.r. runout or less (no expander).
Which would you choose as a starting point?

I have a Forster FL Benchrest Die coming with the neck honed out to .245" dia. I hope it does as well as the Redding FL die.

All above are .223 Remington.

 

[Patriot007]

I agree, I recently went with the method and love it. Very little if any runout

Jim, My concentricity gauge reads in .0005 res.(Neco), and I'm just getting a flicker under .0005 on case neck run out. With that method. With my new Sinclair micro chamber die and K&M Arbor press the bullet run out is about .0006.. I'm not complaining, but I was getting around .0008 bullet run out with my Forster micro meter seating die on my Forster Co-Ax press. I'm in a waiting period for the 21Centry Hydro Press (3 months out). So, I bought the K&M press off of Midway ($113.00) last week, just so I could use my Sinclair chamber micro seating die. I am always happy when the numbers get smaller. I'm still a little shocked that this method really works as well as stated. My FIL and I are still debating on this one. I noticed last night that he was putting in an order for a Forster Bench FLS die, LOL. For even a bigger surprise, he called me today and told me that his Wilson micro chamber seating die had just been delivered. He modified his Lee Cast 50BMG Ed. press to accept the chamber die. So,, He is headed in the same direction. All the proof he needed showed up on target. It's nice when the student can change his mentor for the last 20 years, direction in reloading. It shows that I'm paying attention to details. With all the things to consider, My testing so far shows this to be a more productive and consistent method of case prep. JMHO.