Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
One has to ask why the cases are about to fail with only 3 firings. The first thing that comes to mind is that your sizing die is set to push the shoulder back too far with respect to the rifle's chamber. A magnum rifle's chamber is often about 0.016 inches longer than new brass, so repeatedly sizing the brass back to factory specs results in early case head separation.I have Hornady 300wm brass with 3 firings on them. I found 2 with signs of head case separation. Do you just cull the suspect cases or .........?
Hell I first thought this was going to be about the Pentagon.
It is. Obviously you didn’t receive the code sheet.Hell I first thought this was going to be about the Pentagon.
I have Hornady 300wm brass with 3 firings on them. I found 2 with sings of head case separation. Do you just cull the suspect cases or shit can the whole lot?
First, use a probe inside the case to see if you have stretching and incipient case separation. If so, you have a headspace problem.
If not, and the raised ring is just a bulge, try a collet sizing die for belted magnum case bodies:
![]()
"The main problem with handloading the 300 Win Mag is case expansion that occurs at the pressure ring "just above" the belt. Conventional resizing dies can't properly resize any belted magnum case in this area. These cases soon develop a slight "bulge" around the case (usually after just 2 or 3 firings). When that happens, these cases will begin to stick in your chamber or they will fail to chamber at all. This is a very common symptom when reloading belted magnum calibers. Handloading the 300 Win Mag with our Belted Magnum Collet Resizing Die will increase the life of your cases and insure a perfect fit in your chamber."
Link: Sizing 300 Win Mag cases
I was hoping these would last till lapua released there 300wm brass.
Good point. I wouldn't use Hornady on a dare.I have gone through a gang of Hornady 300WM brass and when they ate about to fail they look just like the pics. I’ve sectioned them and confirmed it. Probes don’t do shit.
Good point. I wouldn't use Hornady on a dare.
I don’t really know I’m going to track that on the new brass better. I also am thinking to anneal befor the first firing?How much is the shoulder growing from new to 1x?
On a belted case with proper headspace it doesn’t really matter because in theory the belt keeps the case against the bolt face letting the soft part of the case blow forward as intended.I don’t really know I’m going to track that on the new brass better. I also am thinking to anneal befor the first firing?
I don’t really know I’m going to track that on the new brass better. I also am thinking to anneal befor the first firing?
On a belted case with proper headspace it doesn’t really matter because in theory the belt keeps the case against the bolt face letting the soft part of the case blow forward as intended.
case head separation is from the firing pin and/or ejector pushing the case forward excessively and the harder head of the case blowing back under pressure stretching the case at the weakest area where the wall transitions to the head.
I do. If you anneal more than they come factory you will set it back to the same baseline. If it’s not as much as factory it won’t hurt anything.I don’t really know I’m going to track that on the new brass better. I also am thinking to anneal befor the first firing?
Sure doesn’t seem that way when blowing out wildcat cartridges.That’s one mechanism causing chs. Another is the force of the combusting powder pushing against the shoulder and pulling the case walls apart. If you bump the shoulder too much it will cause premature chs.
Sure doesn’t seem that way when blowing out wildcat cartridges.
I suppose if you let your brass get rock hard and really push the shoulders back but you’d quickly find brass is so hard you have quite a lot of fun trying to size it.
Now let’s look at the position of typical failure, if case was held back properly the failure point would be up at the shoulder area but instead it’s at the classic area where the thick base cup meets the thinner wall.
So 300 are blowing shoulders off from over sizing?It does work that way in 300WM.
Thanks for the offer I have an annealeezDo you have an annealing machine? If not, I can help you out.
So 300 are blowing shoulders off from over sizing?
ExactlyThey are separating at the case head just like in the OP’s picture from oversizing, despite the belt.