Tiny flash holes...

Status
Not open for further replies.
Joined
Feb 4, 2015
Messages
1,926
Location
Northern Minnesota
Stopped at a gravel pit this afternoon on a bike trip to Lake Superior and back home.

Was just popping the spent primers out of the sorted brass from others in 9mm Luger.
Felt some pressure so I took a look inside of the 9X19 case.

Just curious, Anyone else come across something like this? Manufacturer?


upload_2021-9-19_20-51-12.jpeg

The top one with the small flash hole is a norma.
Underneath it is ac CBC.

Boy, did this test my phonophoto* abilities.

*Picture with a phone.... Did I just make a new word for Merriam- Webster?
Copyrighted here at the time and date stamp.
 
I also have run across small flash holes in 357 SIG brass and a couple other calibers but can't remember the manufacturer.
For 9MM I have enough that they will go to recycle bucket. Other calibers I find will get flash holes enlarged with a uniformer if I need the brass bad enough. We all have our "enough" limits.
 
They went "bang" the first time!??
But I suppose there are analytical studies on flash hole size in 9mm range brass.:uhoh:
 
There is actually two different specs for primer flash holes.
The PPC series of benchrest cartridges uses a smaller spec flash hole than most others.
This allegedly gives a less violent more consistent ignition resulting in a more consistent pressure curve contributing to better accuracy.

I have a box of 20 S&B .22 Hornet cases that are significantly more accurate than any others I’ve ever used. They have flash holes that are too small for a standard punch to fit. I ground down my decamping pin to fit the hole.
I can count on these cases loaded with the rifles favorite load (12.5gr of H-Lil’Gun w/40gr Sierra Varminter HP, Federal small pistol primer) to shoot at or under 3/4” at 100yds. Most other cases will give 1.25 or larger...

But, loading large volumes of pistol amm on a progressive press, the “too small” flash holes can be a pain.
 
If one wants to “fix” primer holes how precise must you be? And why would you bother? (Let’s keep the speculation to the small universe of 9mm and 45ACP plinking rounds.)

Clearly the OP’s examples both went bang for someone and I’ve had many small and large holes that I paid no attention to at all, loaded them the same, and they went bang just fine. (Seems to me, any size from the smallest factory hole to the largest factory hole must work just fine or the factory would change the size.)

Some comments here include recycle(trash) them, they’re a pain, they’re no good…WHY? They work just fine NO?

So, other than we’re all or mostly all, OCD, why do we even care?
 
Enlarging the holes is easy. Just don’t over do it. You’ll likely blow primers if you get too large.

Find a drill bit just a slight bit larger than your decamping pin and drill out the hole.
There are uniforming tools such as depicted above.
 
Enlarging the holes is easy. Just don’t over do it. You’ll likely blow primers if you get too large.

Find a drill bit just a slight bit larger than your decamping pin and drill out the hole.
There are uniforming tools such as depicted above.

But there in is the question. WHY?

Lets keep it to the topic of (case) of 9mm range brass

Why bother with it?
Does it make a difference?
As mentioned it works for Norma and others.

Sounds like a mission for BDS or Live Life and some long term testing!:what:
 
The only "problem" I've heard of with small flash holes (Norma 9mm) is depriming. Some size/decapping dies have stems/pins larger than the small flash holes, with obvious problems. Either I have not tried reloading Norma brass or my stems/pins (Lee 9mm) are on the smaller side...
 
Last edited:
I have an old Texan 30-06 die that I use as my universal decaping die; fits everything up to .45. Some holes may get swaged larger. I don't chase sub inch groups.
 
Norma has very small flash holes. I actually bent a pin popping the holes the other day. Finished up the rest and tossed the Norma cases in the bucket. Ordered some squirrel daddy pins that day
 
I've heard of with small flash holes (Norma 9mm) is depriming. Some size/decapping dies have stems/pins larger than the small flash holes, with obvious problems.
Norma has very small flash holes. I actually bent a pin popping the holes the other day. Finished up the rest and tossed the Norma cases in the bucket.
If you suffer from tiny flash holes, or have enlarged depriming pins...
Or simply drill out small flash holes to match other "normal" flash holes.

One more thing to check when sorting 9mm brass:
  • Steel/aluminum cases
  • Brass plated steel cases
  • Cases with internal step sleeve
  • A-Merc and other headstamp with known QC issues (Inconsistent case wall thickness and/or thicker case wall brass)
  • S&B, RWS and other headstamp with tighter primer pockets
  • Norma brass to drill out flash holes
 
Status
Not open for further replies.
Back
Top