Uniforming flash holes, time well spent

[dellet]

Had to fire form some brass today and had a round that sounded noticeably different and was well outside the group. It was obviously different enough, that I set that case aside.

I hate brass prep, new brass was annealed, formed and shot. Trim and primer pockets would be addressed after firing. No sense wasting time on brass that might not survive forming.

Back at the bench I could not remove the primer from the case in question, Could not get the decapping pin to find the hole. Looking in with a flashlight looked odd. Case badly carbon fouled, couldn’t really see anything. Hit it with Q-Tip grabbed the bore scope and this is what I found.

After correction

A quick look at some others, this was the norm.



Then there were a few like this.



The top one was probably about half way closed, or not completely punched at the factory, possible that the primer had just enough hole to ignite the powder.

I found two or three others like the last photo where you can clearly see an abnormal flash or ignition. Each of those were clearly not fully formed. It was a challenge to get the reamer on the flash hole uniforming tool center up and cut.

I’ve had plenty of flash holes that were garbage over the years, first time I ever took the time to get a look at what happens inside and why time spent on primer pockets and flash holes is well worth it.

 

[RegionRat]

Were these range pick-ups with mixed stamps, or all one they of brass?

 

[dellet]

Were these range pick-ups with mixed stamps, or all one they of brass?

All brand new .357 Mag Winchester. Necked down to .32.

 

[RegionRat]

All brand new .357 Mag Winchester. Necked down to .32.

Wow, I'm bummed to see that.

 

[Ned Ludd]

Obviously that's disappointing. Fortunately, you found the issue and corrected it. My only suggestion would be to check flash holes and uniform them, if necessary, when the virgin brass is prepped prior to the first firing. I do this for every single brass prep, even with Lapua brass, which has very uniform flash holes as a rule.

 

[dellet]

I don’t think there’s a doubt that better brass is better formed, but I learned early on that flash holes can be a problem.

I used a pick that was a just under flash hole size to pick walnut shell out after tumbling. Sometimes it would seem like the pick would go through the hole at a 45 degree angle. So I’m well aware of the problem and benefits.

But.....

I have to admit I just got lazy and thought, “ i’m Just fire forming, what could go wrong and I’ve got to handle it again anyway”.

The more I think about it, after seeing the inside of the case, the odd report was possibly a hangfire. That could have been a bad day

 

[Capt. Oblivious]

Ahh Winchester hits again

 

[rjtfroggy]

And this is why I take a drill bit to all my new brass before I do anything else. (at least 2 sizes over what the hole diameter is)

 

[hoosiermike]

I don't use winchester brass any more because of poor flashholes. A lot of them have burrs on the inside of the case and oblong holes in the primer pocket. I started noticing it about four years ago.

 

[Bill K]

Well, I have had Lapua with the same issue, so does that make it terrible also, or just a factory, no matter the brand, a slip up in the production stage, which will occur with any, due to equipment wear or adjustment ?

Ahh Winchester hits again

 

[dannyjbiggs]

I don't use winchester brass any more because of poor flashholes. A lot of them have burrs on the inside of the case and oblong holes in the primer pocket. I started noticing it about four years ago.

Nothing wrong with using Winchester (although less case capacity), just have to do a "flash-hole sort" along with all the other pleminary tasks with new brass. Aways back, 20 years ago, I purchased a case of Win .308, blue label, and after the flash-hole sort, wound up with around 750 usable cases out of the original 1,000. Made the saved ones as expensive as new Lapua!

 

[K22]

I would say in the last 10 to 15 years, new Winchester rifle cases I've purchases have far more defects than Remington, Hornady or Federal. It not usually for me to find 5% uncorrectable cases in a bag.

However, I have not encountered any problems with Winchester straight wall pistol cases.

Flash hole defects in either rifle or pistol cases are not defects I've encountered thus far. There are some inside burrs, but this is normal for most brands I use so as a standard practice, I always deburr the flash holes with a Sinclair flash hole deburring tool.

 

[hoz53]

Had to fire form some brass today and had a round that sounded noticeably different and was well outside the group. It was obviously different enough, that I set that case aside.

I hate brass prep, new brass was annealed, formed and shot. Trim and primer pockets would be addressed after firing. No sense wasting time on brass that might not survive forming.

Back at the bench I could not remove the primer from the case in question, Could not get the decapping pin to find the hole. Looking in with a flashlight looked odd. Case badly carbon fouled, couldn’t really see anything. Hit it with Q-Tip grabbed the bore scope and this is what I found.
View attachment 1365542
After correction
View attachment 1365547
A quick look at some others, this was the norm.

View attachment 1365545

Then there were a few like this.

View attachment 1365546

The top one was probably about half way closed, or not completely punched at the factory, possible that the primer had just enough hole to ignite the powder.

I found two or three others like the last photo where you can clearly see an abnormal flash or ignition. Each of those were clearly not fully formed. It was a challenge to get the reamer on the flash hole uniforming tool center up and cut.

I’ve had plenty of flash holes that were garbage over the years, first time I ever took the time to get a look at what happens inside and why time spent on primer pockets and flash holes is well worth it.

in my rifle accuracy loads i run a close fitting gage pin through the PP holes every loading to make sure they arent plugged and all about the same. i visually inspect them to againxt a white back ground

 

[Rook 6]

My solution is Starline brass for straight wall cases. Lapua for shouldered cases wherever possible. No need to uniform flash holes with either. I still inspect them, but haven't had to address a single one out of a few thousand to date.

 

[Webster]

Had to fire form some brass today and had a round that sounded noticeably different and was well outside the group. It was obviously different enough, that I set that case aside.

I hate brass prep, new brass was annealed, formed and shot. Trim and primer pockets would be addressed after firing. No sense wasting time on brass that might not survive forming.

Back at the bench I could not remove the primer from the case in question, Could not get the decapping pin to find the hole. Looking in with a flashlight looked odd. Case badly carbon fouled, couldn’t really see anything. Hit it with Q-Tip grabbed the bore scope and this is what I found.
View attachment 1365542
After correction
View attachment 1365547
A quick look at some others, this was the norm.

View attachment 1365545

Then there were a few like this.

View attachment 1365546

The top one was probably about half way closed, or not completely punched at the factory, possible that the primer had just enough hole to ignite the powder.

I found two or three others like the last photo where you can clearly see an abnormal flash or ignition. Each of those were clearly not fully formed. It was a challenge to get the reamer on the flash hole uniforming tool center up and cut.

I’ve had plenty of flash holes that were garbage over the years, first time I ever took the time to get a look at what happens inside and why time spent on primer pockets and flash holes is well worth it.

Bottom photo is interesting. Does the anvil get blown forward partially blocking the flash hole?

 

[dellet]

Bottom photo is interesting. Does the anvil get blown forward partially blocking the flash hole?

No, the blockage is the burr or deformation in the flash hole. It was tough to get a good photo.

It definitely redirects the flame and burn. A case like below, has nice even carbon all the way up the case.


Then something like this, only has carbon on one side.





It was hard to get a good photo, but you can see a clear line where the carbon is only on one side all the way up the case, starting at the flash hole.



Here's the one above that had an evenly dispersed flame



I have known of the benefit of uniforming flash holes and pockets for a long time and have seen it on the target, just changed when I was going to do it with this round of brass. Didn't want to waste the time if cases failed in forming.

Seeing the inside of fired brass and the flame patterns, just reaffirms what the target says and maybe offers some better explanation of why.

Not often you learn something from being lazy, but I did.