Brass not sizing to spec

[JagerDog]

Something else that can happen is when the sizing ball comes back through the neck, it pulls on the neck and resets the shoulder.

[sigstroker]

Lower the die 1/16th of a turn. Slight overcamming won't hurt.
If this is once fired brass that you bought. You may need a small base die.

I turn the die down enough that the shellholder jams against it. I use a case gauge (Dillon, I think) on every sized case.

[Nessal]

IMO, generally it is a matter of the shoulder not bumping far back enough. I turned my dies down with the ram all the way up then another 1/2 turn after.

[ar15barrels]

I turned my dies down with the ram all the way up then another 1/2 turn after.

1/2 turn is a LOT.
That's 0.0357" of die travel.

Most presses are not stretching much more than 5-10 thousandths.
Try only tightening the die 45 degrees (1/8 of a turn) next time.
That should be more than enough.

[Jesse 2]

Brass not sizing to spec

Most presses are not stretching much more than 5-10 thousandths.

[jimmykan]

Sand/mill/grind 0.025" off the bottom of the die and reset for a strong cam over.

This will work if the die was not pushing back the case shoulder enough, but may not work if the die was not squeezing down the case body diameter enough. Still worth a try though.

[ar15barrels]

How to control amount of stretching?
When full sizing tough brass like Lapua, I cannot get consistent shoulder bump (>0.003” spread), especially when lever is pulled multiple times for adjustment.
One shot lube is used, and I notice the changing gap between die and shell holder.
Should I use separate dies for body sizing and bumping?

You are always stretching the press frame while sizing.
You will never get consistent sizing IF you are stopping against an air gap because the air gap allows for inconsistency in stretch.

So you need to eliminate the air gap and go with a steel-on-steel sizing adjustment.
You can do this by using redding competition shellholders or shims between the die and shellholder.
Then you can adjust the press so that you have a hard bump that stops steel-on-steel and your shoulder lengths should be consistent.

[fguffey]

Buying a new sizing die is going to be difficult in the current environment so I want to see if anyone has experienced anything like this or has any ideas on what to try next.

There is no shortage of 223 cases and or dies around here. As to 'around here'. there are no mysteries about what the die, shell holder and press does to the case. All I want to know is 'who/what won', there are times the case wins and there are other times when the press, die and shell holder wins.

too many reloaders stick a case into the shell holder, pull the handle and then expect the case to be sized. I don't,

F. Guffey

[divingin]

Lapua brass is not particularly tough to size. Especially when compared to say, Lake City brass, which is much thicker.

That gap changing is due to differing drag between cases. First thing to do would be to use a better case lube. I'd suggest using Imperial Die Wax, but there are others that work as well (I've had good luck with SharpShootR Royal aerosol lube - just watch how heavy you put it on.)

After that, it may be that cases are bulged differently (comes up as second, as I'm assuming the cases are fired from your rifle, so should be fairly similar. Pickup brass or brass fired from various rifles will be most affected by this.) If that's the case, and you still get sizing variation after improving the lube, you can try leaving the brass in the die for a few seconds before lowering the ram, and you can try running all your brass back through the sizing process again (the initial size will get it close and reduce the amount of drag you see the second time through.)

If you have a lot of firing/reloading cycles on your brass, you may need to have it annealed, as work-hardened brass tends to resist changes.

[fguffey]

Originally Posted by Jesse 2 View Post
How to control amount of stretching? When full sizing tough brass like Lapua, I cannot get consistent shoulder bump (>0.003” spread), especially when lever is pulled multiple times for adjustment. One shot lube is used, and I notice the changing gap between die and shell holder. Should I use separate dies for body sizing and bumping?

Sizing while stretching or stretching while sizing?

Separate dies? One for bumping and another for sizing. If bumping was concern I would use two different presses, I would use one press for all of my sizing and another press for all of my bumping, I can do that because I have bump presses. Other reloaders? They bump because it sounds good.

F. Guffey

[smoothy8500]

Other reloaders? They bump because it sounds good.

F. Guffey

[Jesse 2]

Lapua brass is not particularly tough to size. Especially when compared to say, Lake City brass, which is much thicker.

That gap changing is due to differing drag between cases. First thing to do would be to use a better case lube. I'd suggest using Imperial Die Wax, but there are others that work as well (I've had good luck with SharpShootR Royal aerosol lube - just watch how heavy you put it on.)

After that, it may be that cases are bulged differently (comes up as second, as I'm assuming the cases are fired from your rifle, so should be fairly similar. Pickup brass or brass fired from various rifles will be most affected by this.) If that's the case, and you still get sizing variation after improving the lube, you can try leaving the brass in the die for a few seconds before lowering the ram, and you can try running all your brass back through the sizing process again (the initial size will get it close and reduce the amount of drag you see the second time through.)

If you have a lot of firing/reloading cycles on your brass, you may need to have it annealed, as work-hardened brass tends to resist changes.

Very helpful. Thanks. Also purchased a set of shell holders.

This is 338 brass. It was frustrating to use up all fire formed brass to chase shoulder consistency. It is better now.