Ran into some problems load testing today. Case damage I have never seen before

[sunray]

Does "trying other popular loads I had seen online" mean you have no idea what that case was loaded with? First suspect is soft Federal cases, but as mentioned that isn't going to blow primers. Seriously overloaded ammo does that.
Your 44.0 is fine and so is your starting load, according to Hodgdon. Quit using OPL's though. If you try loads from unverified sources always reduce by 10% after consulting your manual.

 

[Roddy]

Does "trying other popular loads I had seen online" mean you have no idea what that case was loaded with? First suspect is soft Federal cases, but as mentioned that isn't going to blow primers. Seriously overloaded ammo does that.
Your 44.0 is fine and so is your starting load, according to Hodgdon. Quit using OPL's though. If you try loads from unverified sources always reduce by 10% after consulting your manual.

Well let me clarify. I tried other people's load data that was well within the safe limits I had worked up to with my own loads. I handloads each round.

I DID NOT buy some strangers handloads and try them out. I did buy some strangers brass and use it though.

The only thing I changed was charge weight, not COAL, powder, bullet, or primer type. If I can safely use 44 grains why wouldn't I be able to use 43.5 safely? I have read several reloading books and manuals and nothing I could find says a lower charge could cause a problem like this.

I have already scrapped about 20% of that brass due to strange headstamps and marks on the brass. I will probably just toss the rest.

My next batch of brass will be Lapua. I will work with my own factory bought Federal brass until it wears out and then toss it too.

I know Federal isn't great but it's what I had on hand to learn with and I know they produce some accurate ammo so I thought it would be okay.

 

[burnt_servo]

Well let me clarify. I tried other people's load data that was well within the safe limits I had worked up to with my own loads. I handloads each round.

I DID NOT buy some strangers handloads and try them out. I did buy some strangers brass and use it though.

The only thing I changed was charge weight, not COAL, powder, bullet, or primer type. If I can safely use 44 grains why wouldn't I be able to use 43.5 safely? I have read several reloading books and manuals and nothing I could find says a lower charge could cause a problem like this.

I have already scrapped about 20% of that brass due to strange headstamps and marks on the brass. I will probably just toss the rest.

My next batch of brass will be Lapua. I will work with my own factory bought Federal brass until it wears out and then toss it too.

I know Federal isn't great but it's what I had on hand to learn with and I know they produce some accurate ammo so I thought it would be okay.

I would be measuring the case capacity of the different lots of brass before tossing them . .... make sure the case is clean and either has a primer , or used primer installed , then weigh it . fill it with water and weigh the whole thing again .

subtract the empty case weight from full case weight and you have your case capacity in " grains of water ".

water at the edge of the case neck will form a bit of a "dome" due to surface tension . to keep things accurate , keep the dome to a minimum and do exactly the same thing to all the cases ....

using the exact same reloading components , methods and powders , a larger case capacity will give you lower pressures , a smaller case capacity will make for higher pressures .

if nothing else and the capacity's are the same , you just ruled out one more thing as a culprit .

 

[Andy]

I have experienced what you just have a couple of times..........the cause is an oversize flash hole. I was doing load testing for a 243 and everything was ticking along nicely when wham, I got a face full of blow back. Opened the bolt and had the primer exit before the case and the case looked exactly like yours. This was the third in a rack of 4 and only midway to my max loads. I looked long and hard at the previously fired cases and deemed that I was no where near hot yet, so I fired the fourth round without incident. Then proceeded on through the remaining 2 hotter loads without incident.
When back at my loading bench I inspected the failed case very closely and noticed the primer flash hole looked very oversize. I then checked a few other cases I have laying around that had blown primers for one reason or another and the flash holes appeared normal.......HHHMMMMMMM.
This was brand new unfired brass I was working with so no other fools folly had come into play. I then decided to check the rest of the 3 bags of new brass and low and behold I found another one with a flash hole appearing to be about 50% too large. I promptly loaded up the same load as previous and with 4 cases including the oversize flash hole one. Guess what..........exactly the same result......3 good ones and 1 blown case. I did wear a grinder face mask this time..........

PS.......in that photo of the sectioned case that blew, the primer flash hole looks significantly oversize to me.

An interesting point, and at first look I tended to agree, but on closer inspection it looks ok. Standard size is 0.080" and the primer is only 0.210", so there'd be only 0.065" on either side of it.

The OP's sectioning of the case was a real butcher job (no offence intended), but even with all that, the Flash Hole does not look overly large.

IMO, solving this is a Rabbit Hole - there's just no enough info provided and forthcoming to do anything more than speculate.

 

[Roddy]

Yes I did real hack job on the case, literally. However a 2.5 mm Allen wrench fits into the flash hole with room to spare (it's not cut evenly so the flash hole is still mostly there.) There is no where near enough room to fit the same wrench through the flash hole of another case. Maybe that had something to do with it.

 

[burnt_servo]

Yes I did real hack job on the case, literally. However a 2.5 mm Allen wrench fits into the flash hole with room to spare (it's not cut evenly so the flash hole is still mostly there.) There is no where near enough room to fit the same wrench through the flash hole of another case. Maybe that had something to do with it.

the flash hole will expand as the case head expands