RCBS 308 neck size

[Tom Thomson]

I think that my RCBS neck size die (#15530) is working the brass more than neccesary. The neck goes from .344 dia as fired to .329 after sizing to .344 with a bullet seated. Since I am loading single shot, I don't need that much neck tension. Has anyone opened up the ring? How did you get it out? Any ideas?
tommyt

[LongRange]

Buy a lee collet die and a couple of extra mandrels and you can hone the mandrels down to your desired neck tension...

[Robinhood]

I think that my RCBS neck size die (#15530) is working the brass more than neccesary. The neck goes from .344 dia as fired to .329 after sizing to .344 with a bullet seated. Since I am loading single shot, I don't need that much neck tension. Has anyone opened up the ring? How did you get it out? Any ideas?
tommyt

.344 - .308 = .036, .036/2 = .018 wall thickness!?!? I am not doubting your necks are too tight but if your brass has .018 wall thickness per side then you need new calipers. There are a couple of issues with your quoted dimension, you might want to go back and take new notes. If you have calipers measure the internal neck diameter, the OD and then the neck wall thickness. Post those dimensions here.

[Tom Thomson]

rob
you are right. i said .344 with a bullet seated should have said .329. that makes the wall .0155. it's lapua brass, by the way.
tommyt

[Robinhood]

Yea, .329 is wrong also. .3375-.3385 is where you should be. can you post a picture of what you are doing? Something is amiss.

[LongRange]

.344 - .308 = .036, .036/2 = .018 wall thickness!?!? I am not doubting your necks are too tight but if your brass has .018 wall thickness per side then you need new calipers. There are a couple of issues with your quoted dimension, you might want to go back and take new notes. If you have calipers measure the internal neck diameter, the OD and then the neck wall thickness. Post those dimensions here.


Yea, .329 is wrong also. .3375-.3385 is where you should be. can you post a picture of what you are doing? Something is amiss.

good eye RH i missed that...its been awhile since i shot a 308cal.

[Tom Thomson]

Rob
The .329 dia is correctly measured and I know that it's way too small. That was the reason for my original post. I want to remove the bushing so that I can take a bore cut and open it up. I turned a punch to fit but that sucker is in there tight. Can't move it. Guess I'll have to buy a die which offers a selection of bushing sizes.
tommyt

[Robinhood]

rob
you are right. i said .344 with a bullet seated should have said .329. that makes the wall .0155. it's lapua brass, by the way.
tommyt

This can't be, with a bullet seated. That would make the neck wall .0105 thick per side. I don't believe you can seat a 308 bullet if the outside diameter of the brass is .329 and the wall thickness is .015. I believe the brass gets destroyed when seating the bullet.

A Lee die would put your in that vicinity without the expander rod. after the expander rod passes through it is like .335. Your die has no bushing as you stated but it should have an expander that would open it back up.