Body die + Lee collet die -> Full length sizing die 280 AI

This answer may cause disagreement but I find rather I'm sizing to bump shoulder with benchrest FL die and then sizing with collet die or just neck sizing with collet die only I get between 1/2 and 1 thousandth's case neck runout either way. Its when I bullet seat with a benchrest sizer with the sleeve, even when turning cartridge several times as I complete seating stroke the TIR on loaded cartridge is 1/2-1 1/2 thousandth's taken at mid point on bullet. This means I have to adjust runout on about 40-50 percent of the loaded rounds to get all below one thousandth's TIR (this is my personal number I want all at). Hope I explained what you were asking me. Mandrel dies don't give me quite as good TIR numbers. I figure that mandrel in case neck with no support on case outside (like sinclair) vs lee collet die with mandrel in case neck and collet supporting the outside makes the lee produce cases with slightly less runout, I tried both and that was my experience.

But like said earlier in one of the posts.......whatever you are doing to get really good case neck and loaded cartridge runout ........keep doing it if it works for you. I'm a bit over the top on runout and spent quite a bit of time measuring and trying different techniques to accomplish my goals, several members on this site gave me some good ideas that I've combined to get where I'm at.
 
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fightthenoise said:
I currently use a Redding body die to size/bump my 280 AI brass, followed by a Lee collet neck sizing die to size the necks. The ammo is fine, but I'd like to know if there is a single die that accomplishes the same thing to the same standard. I'm mainly trying to consolidate two steps into one step. I'm looking at Redding full length sizing dies but my worry is that I won't be able to set it up to size as minimally as I am with the body/collet dies.
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Did you have Lee make you a custom Collet Die? I've never seen one for the 280 AI and would love to have one
 
dougduey said:
Really??? Great to know, thank you. Do you have to set it up differently?? I'm guessing no
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No sir, no different. Just set up for 0.002 worth of tension. I learned that they were interchangeable on this site so there are a couple other threads about doing it but nothing to it
 
I decided yesterday to make my 250 collet die. I took my 257 Roberts die apart, turned .274 off the collet, moved the collet shoulder back .274". Then I made a .274" spacer to go under the die cap. Lastly, turned the mandrel end off by .274". Essentially moving everything down by .274". It works great and was a lot cheaper than a specialty die from Lee.
 
The lee collet die sleeve/collet doesnt support the case at all. The body floats in the collet and centers up as the collet squeezes the neck. This is why I can use them on all my Ackley Improved rounds.
 
Seabeeken said:
The lee collet die sleeve/collet doesnt support the case at all. The body floats in the collet and centers up as the collet squeezes the neck. This is why I can use them on all my Ackley Improved rounds.
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Agree totally, thats why they don't bend or distort the necks. The neck's alone are sized supported by the collet on the outside and sized by the mandrel inside, floating enough at the top of die to line up.
 
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I recently made a collet die for my 250AI from a donor 257 Roberts die. Using a lathe, I trimmed .274" from the bottom of the collet and mandrel and the made a spacer .274" thick to fit under the cap and it works great and is a lot cheaper than the $70 Lee custom made die
 
Thanks all. This is exactly what I was looking for. I called and talked with a tech at Lee. Long tech story , but in the end, all ya'all said the same thing. Mines on order...tired of pulling the button back thru the neck!
 
Been using the Lee Collet/Body die combo for the past year. Getting 3 to 4 reloads before any need for a bump with the body die. That's with the 6.5 CM. On my 338 Win Mag I need to bump after 2 loadings. Accuracy on the 338 showed noticeable improvement when I began using the Collet instead of partial full length sizing with my RCBS standard FL dies.
 
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