Failing to pass case gauge but unsure why

[m-cz-shadow-2]

Hi all, 

 

Just started loading .40 this weekend for limited (have a decent amount of experience loading 9mm).  My recipe is 180 Gr Bayou's over 4.6 Gr or Alliant Sport Pistol, to an OAL of 1.18 with remington primers and mixed brass.  I am coming into an issue where I cannot successfully case gauge any of my loads.   I have loaded 50 of them so far and 45 of the plunked in my barrel perfectly.  The ones that failed had the same (or close) OAL but the rear of the cartridge would not fit in, similar to the image link below:

 https://imgur.com/a/fss5xra

 

 

Any advice would be appreciated

 

 

[redwoods]

Put it in upside down.

It is probably your OAL since you are using coated bullets. Press it in hard then push it out and look and see if the sides of the bullet have coating missing


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[rishii]

You maybe loading glocked brass

 

brass fired out of glocks have a bulge towards the bottom of the case where it’s unsupported by the barrel 

[Hi-Power Jack]

4 hours ago, m-cz-shadow-2 said:

 

I cannot case gauge my loads.   I loaded 50 so far and 45 plunked in my barrel perfectly.  

 

 

If they PLUNK in your barrel, there is NO problem.

 

Bet the other five will probably also successfully fire in your gun 

 

But, just to be sure, I take the five that do NOT Plunk, and put them

in my practice pile - most go bang anyway     

 

 

Edited August 4, 2018 by Hi-Power Jack

[superdude]

use a magic marker to determine exactly why / where they don't fit. that will determine what you need to change.

 

magic marker method explained here: http://www.shootingtimes.com/reloading/reloading-tips-the-plunk-test/

[MikeyScuba]

Probably the Bullets are in slightly crooked.  That happens to mine, push the round in the gauge and the coating gets scraped off the bullet.  Shot 95% of those rejects ok yesterday.  

[rooster]

If they plunk in your barrel your good to go.  If the rnds sit a little proud in the gauge but fit your barrel you now know that you can get away with that anomaly.

[m-cz-shadow-2]

I took a break as I was getting frustrated last night and worked on it again this morning with a clear head.  It looks like it was my crimp, I backed it out and followed the instructions that came with the the press, and now 90% of my rounds are passing case gauge and all of them are passing plunk.

[rooster]

This is a good article about crimp and how to set it.

https://czfirearms.us/index.php?topic=78873.0

[bulm540]

egw u die is your friend.  http://www.egwguns.com/smithing-tooling/undersize-reloading-die-.40-s-w/10mm/

Edited August 4, 2018 by bulm540

[glassblower]

I load Bayou’s and Bayou coated 40’s are .401 which you need to keep in mind as you balance any projectile deformation, crimp, and gauging. I was having a similar problem with the Hondo Case Gauge and Dennis at Bayou recommended that I use a Lee U die. The Lee die improved the reject percentage and allowed me to remove more of the deformation. I load mixed brass with an OAL of 1.2 and some have suggested that a shorter OAL may lead to additional improvements.

 

i also plunk tested the rejects to see how much of the case could show in the gauge and still pass plunk. FWIW, I loaded some coated .400 with the same settings and almost all passed gauge with no deformation.

 

.......... edited like bulm540, an undersized die will help.

Edited August 4, 2018 by glassblower
Bulm540 response

[schaet]

+2 on the EGW undersized die. I use one for 9mm and will very rarely get one that doesn't gauge! When I say very rarely I mean maybe 1 every 500 rounds! It's awesome! 

 

[glassblower]

For this case of the Bayou .401, I decided to test and see if shortening the OAL to 1.185 improves the gauging percentage, it does not, as a matter of fact, it makes it worse. Not sure what to conclude from this other than I will be resetting back to 1.2.

[glassblower]

Hmmm, just found a very interesting and helpful article regarding the use of case gauges and troubleshooting the cause of ammo not passing.

https://www.shockbottle.com/faqs-1

 

 

[m-cz-shadow-2]

Thanks all will definetly be picking up the undersized die!

[m-cz-shadow-2]

2 hours ago, glassblower said:

Hmmm, just found a very interesting and helpful article regarding the use of case gauges and troubleshooting the cause of ammo not passing.

https://www.shockbottle.com/faqs-1

 

 

I just read through this, what a great resource. Will be saving for reference 

[L3324temp]

Switch to a lee sizing die and this issue should go away.


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[zzt]

m, I had the same problem shooting cleaned range brass.  You don't know what it was fired in.  15~20% of my loads failed the chamber checker.  It was annoying.  Two things solved the problem.  I went to a Mr. Bulletfeeder 2-step expander and a Lee Carbide Factory Crimp die.  The MBF expands the very top of the case to bullet diameter, will the lower part expands less for bullet seating tension.  Bullets fed by a bullet feeder or by hand stand straight up and down, so the seater pushes them in straight.  You do not get the bulge at the top as you would by crookedly seating a bullet.

 

The LFCCD is a crimp die only.  The die body is the one they use for their push through sizing die to remove the Glock bulge.  It sizes on the way down, crimps, then sizes on the way up.  It is rare that I get a round that will not drop cleanly into and out of my Hondo case gauge.  Those that do always chamber and fire, but I relegate them to practice anyway.

[bigedp51]

Something  pistol shooters very seldom do, is trim their cases to the same length. And the problem is the longer cases can bulge below the crimp and not fit in a case gauge.

 

The Lee factory crimp die with the carbide ring in the base is a cheat for those shooters who do not trim their cases.

 

If a longer case bulges below the crimp the carbide ring will size the bulge down and the cases will pass the plunk test in a case gauge.

 

You can put a straight edge the length of the case and if it doesn't lay flush just below the crimp you have a bulge.

 

[Gomar83]

What are the spec’s your using? What’s the max o.a.l. On the brass when you trim them down?

[SlvrDragon50]

On 8/5/2018 at 1:35 PM, zzt said:

m, I had the same problem shooting cleaned range brass.  You don't know what it was fired in.  15~20% of my loads failed the chamber checker.  It was annoying.  Two things solved the problem.  I went to a Mr. Bulletfeeder 2-step expander and a Lee Carbide Factory Crimp die.  The MBF expands the very top of the case to bullet diameter, will the lower part expands less for bullet seating tension.  Bullets fed by a bullet feeder or by hand stand straight up and down, so the seater pushes them in straight.  You do not get the bulge at the top as you would by crookedly seating a bullet.

 

The LFCCD is a crimp die only.  The die body is the one they use for their push through sizing die to remove the Glock bulge.  It sizes on the way down, crimps, then sizes on the way up.  It is rare that I get a round that will not drop cleanly into and out of my Hondo case gauge.  Those that do always chamber and fire, but I relegate them to practice anyway.

Interesting, didn't know that about the FCD!

[bigedp51]

20 hours ago, SlvrDragon50 said:

Interesting, didn't know that about the FCD!

 

The Lee factory crimp die with the carbide sizing ring in its base is a cheat for people who do not trim their pistol brass.

 

The longer cases can bulge  below the crimp, and the Lee FDC will size the bulge back down.

 

The only problem with the Lee FCD is over sized cast bullets can be reduced in diameter with thicker cases.

Edited August 24, 2018 by bigedp51

[zzt]

13 hours ago, bigedp51 said:

The only problem with the Lee FCD is over sized cast bullets can be reduced in diameter with thicker cases.

 

That is absolutely true.

[valerko]

At1.18 OAL it's pretty much your case gauge . I have same issue . Have load long for my SVI and Wilson case gauge is super tight so I just use barrel to check the ammo

[Antny]

Same was happening to me using zero 180 gr JHP and FMJ which are sized .401. Tried Blue bullets which are sized .400 also 180 gr and with the exception of very few, all pass plunk test and almost go in all the way in EGW gauge.