Rookie needs help...bullet wont stay in neck

[RemingtonShooter]

I am not a total rookie, I have been loading 300wsm and 270 for about a year. I just started 7mm Remington Magnum.

I am using once fired brass, redding type s competition dies. The die is a full length sizing die. When seating the bullet, I can push it by hand further into the case. I followed the hornady book and it notes the outside neck diameter of .315 and mine after sizing are .315 to .316. I have tried adjusting the die but it makes no change in neck. I also have some winchester fresh brass and it measures .308 to .310 on the outside neck.

I am sure it a simple answer so be gentle!

N

 

[Tube Man]

Just a couple of thoughts. Have you checked a sized case to see if it will chamber? Reason for asking is to make sure the case is getting fully sized. If it is, I would check the size of your neck expander button. The expander on my Redding 7MM Rem Mag dies measures .282. I admit that I am not familar with Redding competition dies.

 

[RemingtonShooter]

Expander is .282 and the sized casings do chamber, snug.

 

[Bodywerks]

What is the od of a loaded round? Your bushing should be about .002" smaller than that.

 

[ArchAngelCD]

With the very little information supplied it sounds like you are not fully sizing the cases. Usually the main reason for little to no neck tension is the neck isn't resized.

 

[Brno308]

I am using once fired brass, redding type s competition dies.N

Are the brass once fired in the same rifle. If so why would you want to full length size again. Use a neck sizer die only with bushings to attain the correct neck tension.

 

[ShootnMathews]

Use calipers to measure the outside diameter of the neck of a loaded round then buy a bushing .002" smaller than your measurement. That will give you the proper neck tension.

 

[woods]

Down in the top of your die you should have a bushing that looks like this

that bushing will size the outside of the neck DOWN to the dimension on the bushing. Then the expander comes back up through the neck to expand the neck to the expander ball dimension, in your case .282"

BUT if the bushing is not small enough to size the neck down small enough, the expander will not even size the neck

Get a smaller bushing

BTW, you also have to allow for springback on the neck and varying thickness of your brass. For instance if you had a .312" bushing, the OUTSIDE of the neck will be sized inward to .312" and then may springback to .3125" after. On the neck thickness, if you had a case that had thinner neck walls, then the bushing will not size the INSIDE diameter as small as your other cases.

Most reloaders using bushing dies do not leave the expander in. They will outside neck turn for consistent neck brass thickness and do the math to get the ID they want without the expander.