I noticed that in seating bullets with a .006" or .007" grip, which is at least what you get with many standard dies without an expander, that the neck stretched beyond its elastic limit. Seat a bullet, then pull it, and the neck doesn't return to anywhere near the same diameter. That tells me that depending on the elasticity of brass, the bullets will only be gripped so tight, and no more. Since the elasticity changes with work hardening anyway, there is greater variablity in grips therefore giving inconsistent accuracy.
I settled on a .002" grip as being optimum both for consistency and for holding bullets in magazines where they are supposed to stay even through recoil. I'd judge in the heavy recoilers the grip should be greater, or even crimped, to maintain seating depths in those rounds in the magazine, and for consistency.
I normally turn .003 off the expander ball for most of my "big bore rifles" for a better grip on the bullet and when combined with a near full case of powder, I can get by without a crimp, or with a very, very light crimp.
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Ray Atkinson
The best way to find out is to resize in the sizer die and measure the INSIDE of the case mouth using a caliper. That will give you the ID without having to deal with wall thickness. If the ID is more than about 6 or 8 thou smaller than bullet diameter you will have problems with copper shaving off the bullet or collapsed necks and other problems you will come across if you experiment with it.
You just have to work with YOUR reloading equipment to see how it works in YOUR individual rifle. What works in MY equipment may not necessarily extend to YOUR equipment, it may be a starting point though, you just have to try it to see.
I found this out by resizing some 22 cal cases I had turned down to 0.012" walls and wanted to see if I could use my sizer without the expander ball. Even with necks this thin, the ID of the sized case was 0.215". That's 9 thou smaller than bullet dia. I used a VLD bullet ID reamer and even then I got some shaving and necks rolling in on a small portion. Each different die maker will resize to a different ID even in the same caliber. I have 4 different brand sizers in 223 and 22-250 and they each resize the same case to a different neck ID by 0.004" and set the shoulder back by 0.002"!!!
You just have to check it out with your dies and the cases you will be using.
The best bet it to go with the Redding type S dies if you want to eliminate the expander ball problems.
I found using the Redding type S full length resizer works better with my 22-250 and 30-06 and the neck sizer works best with my 25-06 and 223. Don't ask me why right now, I'm still trying to find out myself. I get better groups and less runout doing it that way but may have something to do with the brass, the dies themselves, the rifles, I haven't worked it through yet. As it stands, I will do it this way until I figure it out.
One thing to consider, once you start reloading and going beyond anything other than making standard cartridges you will open up that can of worms and it is a very big can. It is a fascinating hobby with more opinions and bullshit than a convention of Ford/Chevy/Dodge truck owners and shooting enthusiasts thrown in. Enjoy it because the way the world is going it won't last much longer.
Keep the same load and play with it. Also alter seating depth. What you will be doing in each case is altering barrel harmonics.
What caliber?
What is the construction of the bullet?
What is the form factor of the bullet?
What kind of die are you using?
Why do you want to do this?
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