All 9mm Failing Plunk Test and Gauge Checker

[HesedTech]

3 hours ago, Orion1 said:

I am measuring the crimp on on the head of the case, closest to the bullet. When I crimp it more and the bottle resembles a coke bottle is this an issue?

Orion

 

You are over thinking this. This isn't precision rifle loading, so all you need is a consistent finished round which loads in the gun and goes bang at an acceptable power factor. The "coke bottle" is the result of dies undersizing the brass to prevent bullet setback, while the crimp is only to remove the bell to the point it doesn't overly dent the bullet and will plunk test in your barrel. 

 

Last night I just set up a press for 40 SW (same process for 9), and the way I set the bullet and crimp was this:

1. Seat bullet to OAL (PS I already knew what length was needed from previous testing).

2. Slowly crimp/remove bell until it freely plunked.

3. pulled bullet to check for over crimping marks.

4. Repeat the process a couple more time through press stations to verify I have the OAL and crimp set properly.

 

Dies all locked down and ready to run ammo.

 

Didn't measure the crimp once and didn't need to.

 

Now just have to chrono the rounds to check for PF velocity (170+ with 180 grain Blue Bullet).

 

 

 

[Orion1]

Pass. 

 

The issue might have been in the dies themselves. Dillon has a 46 week wait on 9mm dies, so I bought these on ebay. After about 3 weeks of testing, I went ahead and bought a brand new set for $200.. Switched the used dies with new dies and now all my rounds pass. Two lessons learned, dont buy used dies and the plunk/twist test trumps any case gauge checker any day. 

 

I tried applying more crimp to remove that bell several users pointed out. Thanks for your feedback. How does this look?

 

https://ibb.co/QXYHcBQ

 

 

Edited November 13, 2022 by Orion1

[Orion1]

8 hours ago, GrumpyOne said:

"Mouth" of the case. The case "head" is the part of the case the primer goes in. 

 

What I meant was, where on the case mouth are you measuring? You need to measure on the very, very end of the case mouth, as close to the bullet as possible. The easiest way I have found to do this (with calipers, anyway) is to measure the case with the calipers parallel to the case, not at a right angle. Where the caliper jaws are over the bullet, inline with the case, using just the very tip of the calipers. I bet if you did this, your measuement would not be the .376- .377 you claim.

 

The coke bottle shape is actually desired when reloading. It prevents bullet setback.

 

Thanks for the insight. 

[ysrracer]

OP, not enough crimp

[ysrracer]

7 minutes ago, Orion1 said:

Pass. 

 

The issue might have been in the dies themselves. Dillon has a 46 week wait on 9mm dies, so I bought these on ebay. After about 3 weeks of testing, I went ahead and bought a brand new set for $200.. Switched the used dies with new dies and now all my rounds pass. Two lessons learned, dont buy used dies and the plunk/twist test trumps any case gauge checker any day. 

 

I tried applying more crimp to remove that bell several users pointed out. Thanks for your feedback. How does this look?

 

https://ibb.co/QXYHcBQ

 

 

 

Forget how it looks, does it pass the plunk test?

[dmshozer1]

Observations and questions,

Through the years I have used RCBS, Redding, Dillon and Lee dies.

They have all been good to me loading 9,40,45 and.223.

The problem has always been the fact that all brands of brass

are not the same length. Even the same head stamp brass will vary as  much

as .015 from each other.

So what do you set up your crimp die to do? Go off the shortest brass or the longest.

If you set it up for the .015 and then crimp a piece that is .015 shorter, you might have a problem gauging your finished rds.

I have found that case gauges will show the rds. to be ok but checking them in the barrel you are using they might not plunk or spin.

I have also found that before sizing and after sizing that most, not all brass will grow as much as. 010. Then after flaring will

measure less that the stretched rd.

I measure a bunch of my current brass, pick the middle measurement to set the crimp die and then barrel check the gun I am loading for.

Depending on the gun barrel I can get away from most of the  above problems.

I do have a PCC with a picky chamber that requires a barrel check for sure.

I think if for example you happen to pick the longest piece of brass you have by accident and set your die for that length, then

crimp your shortest piece, you might not have enough crimp.

 

 

 

[HesedTech]

1 hour ago, Orion1 said:

The issue might have been in the dies themselves

Sounds like some really bad dies. What is the brand?
 

My experience so far is after 10s of thousands of rounds my 9mm dies (Dillon) still produce good results. Even the Lee dies I use haven’t worn out yet. The only exception was a Mighty Armor 9mm die I tried (about three years ago, new ones are probably better) was just too loose and allowed setback issues. 
 

Glad to see you’ve solved the problem. 

[Orion1]

Thanks!

[vegaspete61]

without reading every word from every reply....

 

Personally I think your crimp is too tight...379 -.380 should be all you need. 

overcrimpimimg will bulge the case just enough to make it fail case gauge,

esspecially the uber tight EGW gauge and a tight match barrel chamber.

 

I only case gauge rounds that I take to matches, it all runs whether it's case gauged or not.