The OP sounds like he has some experience. He wrote that he pulled bullets and re-weighed and got the correct 15g. It is still possible that the first three were overloaded and the next 3 weren't, but that seems very remote. Overloading with 4227 is tough because it fills the case.

OK, so we have too much pressure in the cylinder. Where does that come from besides the powder choice, powder weight, or primer? 4227 is often shown using a magnum primer. That would not account for stretched cylinders.

This makes no sense to me.
It is possible for the 4227 to be a bad batch. But if that were true, lots of people would be blowing up guns. The only reasonable option left is that it is not 4227. The OP indicated a new bottle of 4227 so it doesn't sound like he refilled or transferred to another container. Could your powder measure have had left over different powder from prior reloading?

Has anyone ever successfully proved a bottle of powder was HOT ???

I read the KABOOM stories and the questions raised, but I haven't seen where a company admitted or was proven it had bad powder. Is there such a thing? I had my own KABOOM with factory manufactured ammo.
They used the wrong powder in a lot and had to buy me a new gun.

This is scary stuff as I use a lot of 4227 in almost every caliber I reload. It downloads well as opposed to H110 or 296. I take it to 20g in my 357 Maximums without over pressure signs. 44 Mag loves the stuff.

This is a first for me to hear potential 4227 problems. I'm hoping it's something else. I'll be following this thread with great interest.


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