What do you think is the problem here...case head seperation

[Aggrofish]

I generally FL size and decap in one step. As such I am measuring with the primers in tact to set up the bump. I just deprimed 5 pieces of fired, unsized brass. I took measurements with the primer in and with it removed and on all 5 the measurement was exactly the same. As you can see in the very first picture my primers do not protrude past the rim of the case. I picked up a universal decapping die because I do agree that it will be more consistent and eliminate any possible errors attributed to the primers.

My reloading was probably sloppy being that it's been 110 plus in Vegas and my garage is an oven. The ONLY thing that's changed over the years was the tension on the upstroke of the sizing operation to remove the expander ball. Why I continued to size the rest of the cases when the expander ball took considerably more effort is beyond me. The expander ball was loose. I don't know how much that can mess with a case. I also picked up another precision mic which I find faster and more accurate than the Hornady kit. I'll use them both as a double check and try to slow things down a bit and measure, measure, measure. I started prepping 300 new pieces of brass so we'll see how many firings I get.

We haven't gotten an answer at to whether he is measuring with the primer still in or not. That is important. Every single time I have seen this it is tracked down to excessive sizing and too much headspace. Every single time.

Take a single piece of brass and load and shoot it. You said after firing and before sizing that they chamber just fine. That's a sign that they are not fully formed to the chamber.

Now neck size only and fire again. Check if it'll chamber again. If there is resistance; then pop the primer and measure your base to shoulder datum. Measure your bump from there.

If there is still no resistance when you chamber before resizing then repeat the load and shoot until there is.

 

[Afkirby]

The Hornady 6.5 Creedmoor brass isn't the toughest stuff out there, but it shouldn't have a head separation after 5 firings unless your loads are stupid hot... and with Hornady brass the primer pockets will give out long before 5 firings if the loads are that hot. I have some Hornady 6.5 Creedmoor brass that's been through a semi-auto 6 times and it still is OK down at the web (used the paperclip test and also sectioned a couple of cases.) Primer pockets are another matter with that batch.

Your case head condition and primer condition all look good; I don't see any ejector flow/marks and the primers look great. Last batch of *factory* 140 ELD-M ammo I shot left the primer radii pretty flat.

While your FL die definitely oversizes the neck before expanding it back out, that won't cause a case head separation. The repeated oversizing and expanding will work harden the necks over time, that might be what you're feeling when the expander passes through the neck. Annealing would help that, better yet would be a neck honed or bushing die to minimize neck sizing.

How are you measuring your 0.002" setback? If using bump gauges, what brand?

Reason I ask is I had a similar "oops" myself several years ago where a friend's 22-250 that I was reloading had a couple near head separations after only 3 firings. I was using the Sinclair bump gauges with the tapered shoulder to measure the FL sizing. I didn't realize it at the time, but the ID in the Sinclair bump gauge was too small and was contacting the radius where the neck meets the shoulder and not the shoulder itself-- so the readings were bad. What the Sinclair gauge said was 0.002" setback after being FL sized, a Hornady bump gauge said was 0.009-0.011" setback... no wonder the brass failed so fast. I'm still using the Sinclair gauges, but on many of them I've had to open up the ID to clear the radius of the neck/shoulder junction on the case. Proper neck radius clearance is something I check for very carefully now with the Sinclair gauges and I also keep a set of Hornady bump gauges on hand for a verification.

I had the same issue with my Sinclair gauges in 223.