300 Win Mag brass fatigue?

[midgetorama32]

I've been conducting an "experiment" to see how many loads I can get out of my W-W 300 Win Mag brass. I have been shooting a mild load of Retumbo and 208 A-maxes and anneal after every third firing. I just finished my 10th firing on the brass. All of these rounds were difficult to extract and it looks like the region just in front of the web is expanding a considerable amount causing the hard extraction. I didn't have this issue on loads 1-9. I resized again, and re-primed them. All primer pockets are tight.

Am I correct in my thinking that the brass just in front of the web is getting thin causing excessive expansion in that area and the resulting extraction issues? Has the brass had it and should I nix the 11th attempt at reloading this stuff?

Thanks

 

[rscott5028]

It's hard to know without closely examining the brass in person.

But, you know what they say...
There are old reloaders and bold reloaders, but no old bold reloaders.

-- richard

 

[sakoluvr]

There are a number of reasons for hard extraction. That said, if you got 10 reloads out of a belted magnum case, you done good. Time for new brass.

 

[backwoods83]

My friend shoots 1k ibs and still uses federal 300wm cases from the mid 90s when they were stamped federal and not F-C, he just changed barrels back in the spring, he used 100 of those federal cases, that he weight sorted to shoot that barrel out, just under 3000 rounds. He neck sizes with a bushing die, anneals just enough to relieve the stress and springback in the neck and shoulders, and he full lenght sizes when the case becomes to tight with a innovative technologies body die, so he has some 29 and 30 time fired pieces of.brass. Its all in your loading methods. Fyi he pushes a 210 berger at 2850.

 

[sakoluvr]

Dang. That is impressive!

 

[MagnumManiac]

My only question is this:
Are there any signs that the brass has expanded just ahead of the belt?
If there are no signs, such as a shiny mark where the brass has been 'wiped', then there is no reason to assume that this is the problem.

Do you neck or partial FL (read shoulder bump .002") size each time?

How many times have you trimmed this brass?

Do the cases show any 'wiping' on ANY area?

The reason I ask these questions is that I can get in excess of 20 firings from my comp rifle in 300WM.
I don't run them at full pressure and neck size only until they become hard to chamber, then bump the shoulder .002". I also anneal after every second firing.
On my current batch, I have only trimmed them twice and they have had 22 firings/sizings to date and are still going strong.

The 'bulge' in front of the belt is the normal expansion ring, as found on all cartridges and only becomes a problem to those that FL size every time due to thinning/stretching in this area. A tight chamber and neck sizing almost eliminates this 'phenomenon'. Case length growth is also slowed by neck sizing only, and only partial FL sizing when absolutely necessary.

If you find that your cases have a bulge above the belt, you can FL size back to SAAMI specs and start all over again, but you will have to check that you don't have incipient case head seperations after the initial firing forming again back to chamber specs.
Running a bent paper clip inside the case can 'tell' if there is an expansion/thinning line developing.

gun)

 

[DKA]

Think that I would go with new Brass.

 

[backwoods83]

Yeah buy some new brass! You may possibly have 10 more firings on the brass you have now, but there is no harm in stockpiling.

 

[Broz]

Might be interesting to cut one long ways with a fine hacksaw. Then you could inspect the area closely.


Jeff

 

[newmexkid]

The running of a paper clip inside a belted case has served me well for about 25 years. Take a new case and run a straightened out paperclip inside the case until it hits the inside of the belt...nice and smooth. After you've reloaded a case several times, (I always checked after the 4th reload) take the same paperclip and do the same thing . This time as the paperclip nears the belt you will feel it gets kinda, "scratchy" with a feeling of a rough spot(s). If you feel the, "difference" scrape the inside of the case with the paperclip to make sure it's not some powder or primer residue. When I felt the rough spots on the inside cases in my 300. Win they went into the trashcan. No matter how, "good" they looked on the outside.