Bumping the shoulder???

[wisconsinteacher]

I am confused. I am trying to make a few rounds for my dad's rifle to use for break in.

I started with brass that measured 2. 043" with the Hornady head space guage. My plan was to bump it down to 2.040" (I am using this number because some of the factory ammo is close to this number) I lubed it and sized it with a Hornady FL sizing die and when they come out, they are 2.048 and will not chamber in my rifle. (I don't have dad's rifle here to test) I am thinking the expander ball is making the brass longer???? If I take the sizing ball out, can I then run the brass through and bump the shoulder back down?

Like I said, I am confused on this one. I am guessing it is something simple that I am missing.

 

[joelkdouglas]

WT, I've noticed the same phenomenom for my 30-06. I will read others posts with interest for their input.

I have corrected the problem by turning the die in a touch more and resizing again until the brass comes out as short or shorter than it needs to be for chambering. But I have no explanation for a piece of brass getting bigger while FL sizing.

Of note, I accomplish the above with Redding Body Dies and Redding competition shellholders. There's no expander ball in the body die. And I don't actually turn the die in more--I just switch shellholders, but the concept is the same.

 

[HeathSexton]

Turn the die in farther.


I smoke a case with a match and size brass until there is a small scuff on the shoulder, then I measure. This is usually .0015 to .002 setback.

If you think the expander ball is a problem get some 600-800 grit sandpaper and chuck it up in a drill, wrap the paper around the ball and polish it. I do that to all my expanders before I even set the dies up.

 

[wisconsinteacher]

I got it figured out. I really screwed the die down to get where I had to get to.

 

[woods]

Like others have said, turn the die in further

The shoulder measurement getting bigger when running through the die is because

1. The die first contacts the case body at the pressure ring close to the case head
2. As the die squeezes the case body it will increase the body length toward the shoulder, much like squeezing a balloon for lack of a better description
3. You must set the die in far enough so that the die pushes the shoulder back

This is the most common (not all since dies, chambers and cases vary) settings using "0" as the die just touching the shell holder

-3/4 turn - die does not size case body but will size approx. 3/4 of neck
-1/2 turn - die starts to contact case body close to case head and pushes the shoulder forward
-1/4 turn - die sizes almost all of case body and almost all of neck but has not reached shoulder yet
0 - die has sized all of case body and all of neck but has not pushed the shoulder back far enough to relieve crush fit in chamber
+1/8 to +1/4 turn - die has sized all of case body, neck and pushes shoulder back some amount (amount depends upon exact placement of die downward)

Now that is typical. Much of it will depend upon how large your chamber is in relation to the interior dimensions of your die. For example if you have a tight chamber and a large dimensioned die then the die may not contact the case body and balloon the shoulder forward and the opposite is true that if you have a large chamber and a small die then you will greatly reduce the case body and have extreme forward shoulder movement.

You just got to figure it out for each rifle, case and die

 

[joelkdouglas]

Woods, thanks. That makes sense how a brass piece could get larger during the FL sizing process.

 

[JD338]

Make sure that you also lube the inside of the case mouth.

JD338

 

[hubcap]

Make sure that you also lube the inside of the case mouth.

JD338

Very important.

 

[tjen]

For the cartridges I partial size I set the dies to zero and the use shims under the locking ring to move the die up a known distance. I do not want to bump the shoulder and can see on the case neck where the die stopped. I keep the shim information in the die box and if I ever need to decrease the shim length to chamber a case I can at that time.

This would allow for loading for different rifles as well just keep the information on each rifle and shim acordingly. I do the same for my body bump dies too.

 

[rick smith]

The body of a case will make contact with a FL die before the neck reaches it's sizing area. Prove that to yourself by hand inserting a fired case into a FL die. Therefore you are getting some body sizing at -3/4. Rick.