I asked this question near the end of the thread on excessive runout, but did not get an answer, and I really would like to know: If you decap using a universal decapping die; resize your rifle case without the decapper in it; will the "undersized" inside neck diameter cause problems? Ku-dude

I leave the neck expander in the die...I just adjust it so it doesn't extend down enough to reach the primer hole.

If you use a Redding S die with the proper insert to size your neck you`ll have no trouble. Standard RCBS, Redding,Lyman,ect over size the neck and need the expander ball to open the neck back up to just under bullet diameter. Seating a bullet in a case sized with a std sizeing die will lead to buckled necks and ruined cases. If your only loading one cartridge, the Lee collet dies use no ball and for neck sizeing / decapping and seem to work well. They reduce run out for me once you get the hang of adjusting them.

I did a number of tests using a Redding S neck die on a 338 Win Mag with various grips on the bullets. In my checks, the lighter the grip, the better the accuracy. When you get up above .003" grip, (difference in neck diameter before and after seating the bullet,) accuracy seemed to deteriorate a bit. Optimum in my test for accuracy was .001" grip. Only problem with that is that bullets in the magazine have their seating depths altered upon recoil. In my case the bullets were driven back into the case.

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.

If you do that with a conventional resizing die, the inside diameter of the neck will be too small to accept the bullet.
The pressure exerted on the case mouth by the base of the bullet when lowering the ram of your press will colapse de shoulder and wrinkle the neck of your case.
Montero

All this colapsing the shoulder is true enough, but not in all cases, you must try it and see, many times you will be just fine..

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

ray@atkinsonhunting.com
atkinsonhunting.com

Yes you will have problems if the inside of the neck is more than .003" smaller than bullet dia.

In a word, Ku-dude, YES, if you are using standard sizing dies. Now to qualify the statement.

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.

[ 06-15-2002, 02:25: Message edited by: centerpunch ]

Interesting topic,If I dont use decapper,neck sizing,should I go 2 or 3 grs lower near max load,playing with the depth of case neck,will it compensiate for extra grip...

Changing the grip doesn't change the pressure nor the characteristis of the propellant, it just changes the point in the ignition cycle at which it reaches the peak pressure. Seating depth does the same thing. Changing the propellant weight alters everything and for all intents and purposes it's a totally different animal.

Keep the same load and play with it. Also alter seating depth. What you will be doing in each case is altering barrel harmonics.

Depends on several items.

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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