Both.And does the military have those requirements for the sake of accuracy or is it because they dont want their bulk ammo all arriving with the bullets pressed back into the cases?
@Bart B.I think "neck tension" with dimensional units is a poor descriptor for how tight case necks grip bullets. Here's why.
Turn 11 case necks also their thickness ranges from .007" to .017".
Size them so all their mouth diameter is .002" smaller than bullet diameter.
Which case neck wall thickness grips bullets the tightest?
Will soft brass case necks grip bullets with the same force as hard brass; all other things equal?
Do expander balls size case mouths to their exact diameter?
Military small arms ammo has a release (extraction) force spec for so many pounds is required to push or pull the bullet out of case necks. No such specification in SAAMI specs.
Machine shop term for pushing something into a space a tiny bit smaller than it is called an "interference (or press) fit." A couple thousandth inch interference fit will have a big range of extraction force needed to separate them; a lot for a bullet in a hole of hardened steel, very little for a hole in a marshmallow.
@Bart B.
When referring to neck tension, I am referring to the measured amount I size down the neck in relationship to its stretched measurement of the loaded round. The word "tension" means "state of being stretched", that in return for "neck tension" solely is referring to a measured amount of stretch of the case neck on the bullet.
Example:
0.267" = measured neck diameter after sizing, but before seating a bullet
0.269" = measured neck diameter after the bullet is seated
0.002" = the difference, and amount of measured neck tension in inches
Just my 2-Cents
Donovan
@AlloyTargets
I do both; size with a bushing, then my last case prep step is to expand with a mandrel before seating.
Donovan
@AlloyTargets
I do both; size with a bushing, then my last case prep step is to expand with a mandrel before seating.
As the case body is not held, is there a risk the mandrel does not align and create run out?
I've no interest as to what happens to case and bullet after the primer fires.
When it comes to clearance and centering the case I use feeler gages, I know, reloaders must have small base dies, I have small base die, I do not use them but I have them just in case. I understand the die is limited in its ability to reduce the diameter of the case head because of the deck height of the shell holder. My shell holders have a deck height of .125". According to C&H (El Monte, Cal) in the 60s they designed and made dies that were to be used with shell holders with a deck height of .125", for reloaders that read instruction know that because the C&H die box had the instructions printed on the bottom of the box. Today reloaders believe they have to match brands of dies with brands of shell holders because of the deck height. And I ask? "How fundamental is measuring the deck height of a shell holder?".
And then we go back to the shell holder and deck height, I can turn a standard die into a small base die with a feeler gage. I know that provokes, but I can also increase the presses ability to overcome the cases ability to resist sizing at the same time and I can use the feeler gage to size cases for short chambers at the same time.
F. Guffey
Anyone who would like to thank Jay PLEASE speak up. Thanks Jayoh, FFS. Get over it. If you *really* need it, I can give you a Google search that will provide thousands of examples of nomenclature that is not "technically correct", yet somehow, people still manage to communicate their meaning. Out of all your 1500+ posts, at least half are some variation of this stupid post. Just stop it already.
When it comes to clearance and centering the case I use feeler gages, I know, reloaders must have small base dies, I have small base die, I do not use them but I have them just in case. I understand the die is limited in its ability to reduce the diameter of the case head because of the deck height of the shell holder. My shell holders have a deck height of .125". According to C&H (El Monte, Cal) in the 60s they designed and made dies that were to be used with shell holders with a deck height of .125", for reloaders that read instruction know that because the C&H die box had the instructions printed on the bottom of the box. Today reloaders believe they have to match brands of dies with brands of shell holders because of the deck height. And I ask? "How fundamental is measuring the deck height of a shell holder?".
And then we go back to the shell holder and deck height, I can turn a standard die into a small base die with a feeler gage. I know that provokes, but I can also increase the presses ability to overcome the cases ability to resist sizing at the same time and I can use the feeler gage to size cases for short chambers at the same time.
F. Guffey