.300win mag case resizing

[Joe Kidd]

After I do a partial(neck) or full length resize on some PMC brass, I notice the bolt closes with a little more resistance than what I normally feel from un-belted calibers. This is the first belted caliber I've reloaded for. Is this the belt-forward bulge I've read about? I can see a slight drag mark on the headstamp from the bolt face. I'm using a standard RCBS 2-die set, in a new X-bolt rifle. BTW the bolt will close with no effort on factory ammo. Thanks for your help.

 

[nso123]

Sounds like the shoulder might not be getting bumped back far enough. Are you setting your dies up to bump the shoulder back?

 

[Joe Kidd]

Sounds like the shoulder might not be getting bumped back far enough. Are you setting your dies up to bump the shoulder back?

Yes. Even bumping the shellholder at the top stroke. I'll try some Fed brass when it comes in to see if any difference. These are 13yr old factory 150's and are a bit hot based on primer indications.Thanks

 

[Joe Kidd]

I believe the slight bulge above the case belt is my issue. Fired cases are running around .515, whereas factory brass is around .510. I'm going to borrow a belted magnum collet resizer and try that. Hopefully that'll allow my brass to fully chamber. If that's the case I can go back to neck sizing.

 

[X-fan]

Yes. Even bumping the shellholder at the top stroke. I'll try some Fed brass when it comes in to see if any difference. These are 13yr old factory 150's and are a bit hot based on primer indications.Thanks

The neck sizer does not "size" the shoulder or body.
If you are full length sizing (with a full length sizer) and you are bumping the shell holder against the die you can expect a separated case head.

Have you checked the case length?

I have shot out multiple magnum barrels and have never had an issue with the belt "bulge".
I bought the swedge tool and it makes old crusty cases chamber a bit nicer, but the odds of that being your trouble are remote unless the brass was fired in in a different sloppy chamber.

 

[Joe Kidd]

Case length is good. My point with FL resizing and bumping the shellholder was to insure the case was fully sized. If I only do a partial or FL resize, the bolt drop resistance is the same, indicating I may have a issue on the belt end. I only have this PMC ammo at present and hope to try other headstamps soon. Could be the chamber area near the belt is a issue? I don't know. Thanks for the input. I could live with it, but it is a slight oddity.

 

[nso123]

Are you crimping your rounds? If so, there is always the chance that you are over crimping and making it difficult to chamber. Other than that, I have also shot a bunch of 300 WM over the years, and have never had belt bulge either. Is your measurement of .515 right in front of the belt? I just measured a bunch of rounds that I just loaded, and found my Winchester brass was .511-.512 in front of the belt after FL sizing, and my Federal brass was .514. All of these rounds chamber just fine in my rifle, so I don't know if that is your problem.

 

[Joe Kidd]

Just chambering brass only. .515 in front is correct. Checked a few more unfired cases last night. Some at .508. Hope to solve it soon. Thanks

 

[Jig Stick]

For what its worth...I use winchester brass in my 300wm. I size only with a Lee collet neck die. I have 5 firings on the brass, and still have not had problems with the brass growing. I havent touched the shoulder at all. And I have a standard size chamber.

 

[jsthntn247]

I am having the same problems with my 300 right now. I bought a Larry Willis collet die and it fixed the problem. I was running the brass to hot and it was causing it to swell, I backed down the powder and it's not doing it anymore but the groups suck, go figure.

 

[Joe Kidd]

Hopefully that'll solve my issues. I'm borrowing one Sun or Mon to give it a try. I spoke with Larry earlier and he indicated this issue is frequent even with lighter loads. Thanks for the info.

 

[Joe Kidd]

I got a few once-fired Fed cases today. After a FL resize the bolt drops freely on these. Both headstamps(PMC vs. Fed) are well under max OAL, with no changes to the sizing die. Go figure. No PMC brass in this rifle. Thanks guys for your patience.