I've run into a problem I've never encountered in my short 2 years of reloading--when trying to seat new bullets in once-fired 300WM brass, the neck is too large to seat a new bullet after resizing and running the charged brass into my seater die. The bullet will simply ease in and out of the case mouth after attempting to seat the new bullet.
Everything works great with new brass, but when trying to reload it, I'm having problems. What am I doing wrong?

Are you sure that the size die is adjusted correct and actually sizing the neck. If it is not the case will allow for a bullet to just drop into it.

Sounds to me like the expander plug is too big. After resizing the brass and decapping, try running the cases through again with the expander plug removed. If the problem still exists, it could be the die is defective. If the problem is fixed, then you need a new expander plug.
Paul B.

Mic up the expander plug,and see if it matches
the casemouth Dimensions

If you're errantly using a 338 mag die instead of a 300 WM die this will happen as well.....sure you're using the right die?

I've certainly wondered if the sizing die was doing its job. I've never had to adjust or change it in any way other than the initial adjustments for the case length when brass is fully inserted into the sizing die.
Is it common for an expander plug to need replacing?

What kind of Die are you using to resize. If it's a Lee Collet die, it's not closing on the case neck.

quote:

Originally posted by trigger:
What kind of Die are you using to resize. If it's a Lee Collet die, it's not closing on the case neck.

It's an RCBS die.

This die wouldn't happen to be a Redding F/L sizing die would it? I had the same thing happen a couple years ago with my 300WSM, called Redding and they put me through a few hoops and had me send the die back to them with 4 fired but not resized cases and about four or five days later recieved a new die with the 4 pcs. of brass. The new die works like a charm. I bought the set of dies from Sportsman's Warehouse in Loveland, CO. and they were marked way down compared to all the other calibers of Redding dies and, after the fact, it makes me think someone had returned this set of dies for refund or something. Anyway, I guess it could be a die problem of some other manufacturer also.

quote:

Originally posted by vapodog:
If you're errantly using a 338 mag die instead of a 300 WM die this will happen as well.....sure you're using the right die?

It's the right die. The next larger die I have is a .375 H&H and I haven't used it in over a year. In my case, I had been loading up about 20 new bullets using new brass. After shooting a few rounds to site in the gun, I took the once-fired brass in to load them back up. It was then I found that the necks were too big to hold the bullets, even after resizing.

do you turn necks?

You say you've been using new brass. Well factory brass is supposely sized ready to prime and load. Try this. Run some new brass into the sizer die, then see if the bullet is a lose fit. If it is, then you have either a too large expander or a bad die. Let us know. Hope you have some new brass to try this on.

Are you full length or neck sizing? It may be difficult to tell if you are getting the neck sized while sizing the whole body.

Either way, unscrew the exander/decapping pin and remove it from the die. Size a case. Does this help?

Take your decapping pin/expander and put it in the mouth of a once fired case. How does it fit?

What model RCBS die? Is it a bushing die?

Regards,
Jim

It could be that the new brass is too thin.
Try some of your old brass that you have reloaded before.

Hi, Spring,

If you need your loads and have a universal decapper, decap the brass, remove the expander from the sizer, and resize. Put the expander back in, and just kiss the neck to "bell" the neck a bit. Then cap, charge and seat the bullet.

It could be the bullet, the brass, or the expander, but its probably not the die.

Good luck. Let us know how it turns out. Kudude

I had the same problem with my RCBS die. If the "rod" that holds the expander and decapping pin is bent you get case mouths that are too large and not concentric.

Not enough neck lube can also cause this. As well as an expander thats too large.

Mic your bullets to see if they are the right size. I recently opened an older box of Hornady RN 308's and they were 307; you could twist them around in the case necks easily.