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Expander Mandrel Ford or Chevy

Ok I'm thinking of enter the dark world of Expander Mandrels starting with a 6mm. not limited to but Sinclair and 21st. Century seam to be more commonly listed. then you got the Pin gauge option which opens up to a whole new world of basically any diameter that you would like to try. Let me 1st. say I'm kinda middle of the road guy and not interested in wearing out a barrel trying every combination know to man. in the 6mm it's like the common choice is either .241 or .242 basically 1 or 2Kth. less than bullet diameter. without starting the Ford or Chevy debate I would like to hear any pro's or con's about not only about brands, die body but size as well, tips of the trade and other options. best place to buy, etc.
thanks for your input.
 
Just get the one you like the looks of they are about the same price either way. Shoot for .002 neck tension. I have the Sinclair version and am very happy with it but the 21st Century looks just as good to me. Ford Chevy may just come down to the dealer you want to do business with. I wouldn't consider the pin gauges if you want to keep things simple.

I'm not too sure but I think the mandrels may fit either brand of die.
 
I use a Hornady bullet puller with a set of pin gages . I bought a set on ebay that goes up to .250" covers my .223 and 6mm . I give the gages a radius . I let it float with a Lee lock ring/rubber o-ring . I use graphite to finish size and lube at the same time. Simple,but works fine for me.
 
I use a Hornady bullet puller with a set of pin gages . I bought a set on ebay that goes up to .250" covers my .223 and 6mm . I give the gages a radius . I let it float with a Lee lock ring/rubber o-ring . I use graphite to finish size and lube at the same time. Simple,but works fine for me.

Me too. Works well and I have 0.0005” steps to work with.
 
choice is either .241 or .242 basically 1 or 2Kth. less than bullet diameter. without starting the Ford or Chevy debate I would like to hear any pro's or con's about not only about brands, die body but size as well, tips of the trade and other options
Just things to consider:
- how are you currently controlling how much you size your necks? (bushings as an option)
- do you anneal?
- realize the spring back works in the opposite direction of sizing springback
- if you need to open the necks up much, it can take more effort than you might realize
- if you don't open them up enough in the expansion, you don't get the benefits

I use the 21st Century expanders and I'm happy with them. I also have pin gage sets, but the concept of trying to use them seems slightly barbaric to me (I don't have a good way to radius them to my satisfaction, and some of the holders I question what the concentricity would be). I can't imagine where 0.0005" increments isn't adequate. I can't see carbide expanders being necessary. But these are all just my views and I realize they differ from others experience.

I have probably done more true case neck expansion for turning necks and reforming brass (30-06 to 25-06).
 
Thanks all very good input which helped me make the call and maybe Help others as well. And Basically it did come down to the dealer. Accurate arms and ammo had the Sinclair die body and .241 and 242 mandrels which I saw were out of stock at most places. I do Anneal and I do use a bushing die. All of which have worked fine I was just encouraged by a very good shooter to add the mandrel to my reloading Routine. I guess we will see later this week how it plays out
Thanks again for your input
 
I use the 21st Century stainless steel mandrels. They fit very nicely into the Sinclair/Brownells Gen II Expander Die body:

https://www.sinclairintl.com/reload...ls/generation-ii-expander-dies-prod38807.aspx

I have been very happy with the performance of these mandrels. In my experience with Lapua brass that has not been neck-turned, a mandrel that is only .0015" under caliber will give you very close to .002" neck tension/interference fit due to spring-back. I generally use a bushing that is .002" smaller than would normally give the same .002" neck tension to size the necks down first, then open them back up with the mandrel as the final neck sizing step. For example, I would use 0.248" and 0.336" bushings for .223 Rem and .308 Win, respectively, as the sole sizing step to yield approximately .002" neck tension. When I want to use a mandrel for sizing these necks, I go with a 0.246" or 0.334" bushing, followed by a 0.2225" or .3365" mandrel, respectively.

I also have a couple .308s with ejector springs strong enough to flat-spot the necks upon extraction. I routinely use a much larger diameter mandrel (0.3115") to largely remove the flat spots prior to re-sizing with a bushing die.

The .0005" diameter increment of the mandrels from 21st Century will allow generating different neck tension within a fairly useful range. Just be aware that generating the desired neck tension in brass from different manufacturers may require having several different sizes of bushings in addition to the mandrels due to the fact that the brass may have slightly different neck wall thicknesses.

All in all, I find it very useful to have a set of several different size mandrels for each caliber I reload.
 
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Also use the Sinclair Gen II Mandrel Die , and follow a similar process as Ned Ludd . The difference being that I use a .335 Bushing , which gives me a .3065 I.D. , followed by a .3075 Mandrel . If the prepped cases are stored for any length of time , I run a .307 Mandrel through them before loading , just to create a normalized fit . Some cases you can feel the mandrel getting pressure , and some not at all . But I can feel the "drag" as it goes in , even on the ones that exhibit no pressure . Checking with a pin gauge , .307 will go smoothly into the necks , as I am looking for only a .001 neck interference .
 

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