Plunk Test Failure????

[Telum Pisces]

OK, I reloaded a batch of 230Gr 45 ACP FMJ RN that fail the plunk test. I coated the round in a dry erase marker and plunked and turned the round. The round does not turn after plunked. It does fully seat where it should. It just does not turn in the barrel/chamber.

I took out a factory round Winchester White box 230 grain FMJ to compare. The factory round passes the plunk test. The reloaded round is the exact same COAL as the factory round at 1.260.

I took my caliper to the rounds and at the top of the case mouth, the bullet is .437 for the factory round and my reloaded round is .450 This is right where the marker trick is showing me the problem. The rounds chamber and extract fine.

Is this a reloading issue or a bullet issue? I guess I am asking is there something I can do to fix this or is it simply the bullet design? I can seat it a little further in I suppose. You can see the missing strip of black marker where it rubbed off after turning in the barrel.

 

[joneb]

The round is over crimped. Adjust the die so that it just removes the flare at case mouth.

 

[Ruger 15151]

+1 on over crimped. There is no need to crimp a 45 ACP bullet. You just want to remove the flare created by the expander die. Your finished round should be about .471 at the case mouth with a standard 451 diameter 45 ACP bullet . Any less and you are crimping the case which is NOT what you want with standard 45 ACP loads and FMJ or copper platted bullets.

 

[Telum Pisces]

I thought about it being over crimped after looking again. It was my first time setting up for 45 ACP. I see the issue now after you guys pointed it out too.

 

[LiveLife]

230 gr 45 ACP FMJ RN ... The round does not turn after plunked. It does fully seat where it should. It just does not turn in the barrel/chamber.

The reloaded round is the exact same COAL as the factory round at 1.260"

Usually fully chambered round not spinning is due to bullet nose/ogive hitting the start of rifling unless the case neck bulge is contacting the chamber wall or case is not fully resized.

So resize some brass first to make sure they all drop freely in the barrel with a "plonk" and fall out freely.

case mouth ... is .437 for the factory round and my reloaded round is .450

Did you mean .473"?

Straight walled semi-auto cases headspace on the case mouth and too much taper crimp can not allow the case mouth to headspace with the chamber. .450" is too much taper crimp and likely jamming the case mouth in the chamber and preventing the round to spin.

As to taper crimp, I usually add .022" to the diameter of the bullet for for .451" sized bullet, your case mouth should measure no more than .473". Try using less taper crimp (Or no taper crimp) and see if the round spins after being chambered. If not, try incrementally seating the bullet deeper by .005" until it does.

Comparison picture shows factory PMC/CCI OALs next to Berry's reload with .473" taper crimp. The Berry's reload will fully chamber and spin freely in my railed Sig 1911 XO with tightest chamber and shortest leade I have seen.

 

[joneb]

Your finished round should be about .471 at the case mouth with a standard 451 diameter 45 ACP bullet

My finished 45 acp rounds end up measuring .470" to .473" with .451" depending on the brass.
Here's a fuzzy pic of a 380 acp and a 45 acp, https://www.thehighroad.org/index.php?attachments/005-jpg.208735/

 

[fxvr5]

As I read this, your .437" and .450" refers to the diameter of the bullet just ahead of the case mouth, right?

If i'm seeing your picture correctly, the crimp looks fine. Measure it and let us know what it is.

You might have a really short throat - like almost nonexistent, and that's why it's failing the plunk test. What gun/barrel is this?

Try seating the bullet deep until it passes the plunk test, and let us know what the OAL is.

The shape of the bullet nose (ogive) varies from one brand to another, and each brand might have its own OAL to pass the plunk test.

 

[Telum Pisces]

OK, I seated the bullets down to 1.250 instead of 1.260 and it passes the plunk fully now!

This was on a S&W Shield .45

The crimp was not too much. They were lightly crimped. The picture just shows an odd angle like there's a lot of crimp for some reason. But seating the bullet another tiny bit fixed the problem. So with these bullets, the Ogive was just different and needed to be seated a tiny bit further.

 

[Telum Pisces]

As I read this, your .437" and .450" refers to the diameter of the bullet just ahead of the case mouth, right?

If i'm seeing your picture correctly, the crimp looks fine. Measure it and let us know what it is.

You might have a really short throat - like almost nonexistent, and that's why it's failing the plunk test. What gun/barrel is this?

Try seating the bullet deep until it passes the plunk test, and let us know what the OAL is.

The shape of the bullet nose (ogive) varies from one brand to another, and each brand might have its own OAL to pass the plunk test.

Yes that was the measurement right above the case mouth. Was not sure why it was that much different compared to a factory round I had on hand. But it seems to pass the plunk test now that I seated the bullets for a shorter OAL.

 

[Skgreen]

I took my caliper to the rounds and at the top of the case mouth, ,,,, my reloaded round is .450 This is right where the marker trick is showing me the problem.

Careful now,,, 45 acp headspaces on the case mouth.
As 45 acp bullets are 'roughly' .452, and the case mouth has been crimped down to .450, the cartridge isn't headspacing correctly. Instead of stopping in the chamber where it should, the brass case is sliding up into the barrels throat, with the entire cartridge not stopping it's forward travel until the bullet reaches the lands.

Easy enough to remedy,,, Ease up on the crimp first then check the plunk .

 

[fxvr5]

OK, I seated the bullets down to 1.250 instead of 1.260 and it passes the plunk fully now!

This was on a S&W Shield .45

So with these bullets, the Ogive was just different and needed to be seated a tiny bit further.

Cool. Glad you have it figured out.

Yes that was the measurement right above the case mouth. Was not sure why it was that much different compared to a factory round I had on hand. But it seems to pass the plunk test now that I seated the bullets for a shorter OAL.

I was surprised to see the diameter of the factory bullet at .437 just ahead of the case mouth, and with an OAL of 1.260. It means that the bullet's shoulder is below the case mouth. That's one long bullet nose! But it reminds us that every bullet is different and each has to be checked for passing the plunk and rotate test.

 

[fxvr5]

Careful now,,, 45 acp headspaces on the case mouth.
As 45 acp bullets are 'roughly' .452, and the case mouth has been crimped down to .450, the cartridge isn't headspacing correctly. Instead of stopping in the chamber where it should, the brass case is sliding up into the barrels throat, with the entire cartridge not stopping it's forward travel until the bullet reaches the lands.

Easy enough to remedy,,, Ease up on the crimp first then check the plunk .

You might want to read it again, because your analysis is incorrect. But you're not the only one!

 

[Ruger 15151]

what is your measurement of the case right at the case mount? The diameter of the bullet at the case mouth doesn't mean anything?

 

[fxvr5]

OK, I seated the bullets down to 1.250 instead of 1.260 and it passes the plunk fully now!

This was on a S&W Shield .45

The crimp was not too much. They were lightly crimped. The picture just shows an odd angle like there's a lot of crimp for some reason. But seating the bullet another tiny bit fixed the problem. So with these bullets, the Ogive was just different and needed to be seated a tiny bit further.

Now I wonder what my S&W M&P45 barrel's throat is. I'll have to check it. My S&W M&P9s have short throats and require bullets to be seated very deep to plunk and spin.

 

[Telum Pisces]

Also ignore my info about the measurement of the bullet at the case mouth. I couldn't operate a caliper at that moment in time apparently.

Factory WWB on the right and my reload on the left here in this picture. You can see that the profile/shape of the bullet is different. Just goes to show you that you need to check each bullet that you load to make sure it fits in your barrels etc... The load data is starting point. Then you must do other functional checks as well.

 

[fxvr5]

Also ignore my info about the measurement of the bullet at the case mouth. I couldn't operate a caliper at that moment in time apparently.

Thanks for the correction.

 

[mdi]

I measured the case mouth after "crimping" in about 1990. I stopped when I discovered the Plunk Test, and put away my cartridge gauge about 10,000 rounds ago (Maybe a slight exaggeration, but not by much!). Newer semi-auto reloaders overthink the "crimp" process and screw up their ammo with way too much crimp. Neck tension holds the bullets in all of the semi-auto cartridges I load, no additional crimp/squeeze needed. I just use a taper crimp die to "deflare" my cases enough to plunk 100%. Works quite well in 3, 45 Auto guns I own...

 

[fxvr5]

Crimp was not the issue here, even though nearly everyone thought it was.

I see post editing. Can't have the self-proclaimed experts showing misjudgment. Yet, the remaining text is just as damning. Keep editing!

 

[LiveLife]

I see post editing. Can't have the self-proclaimed experts showing misjudgment.

Yes, the post edit was made after OP clarified the measurement of case mouth vs bullet nose above the case mouth. And since OP clarified, I deleted the content that no longer applied.

And are THR members always correct in our judgement? Of course not as we are all human but as a group, we offer our experience and knowledge base, whether right on the money or incorrect, to other members asking for help, especially those new to reloading.

Yet, the remaining text is just as damning

If you take the entirety of my posts, you will find that most of my posts are attempts at helping OP identify reloading issues presented and work towards determining the cause and hopefully arrive at correct solution. Do all the long-time THR posters correctly identify the problem and offer correct solutions all the time?

No, but what matters is that they took the time to help the OP perhaps troubleshoot or look for another cause but together as a "community" of reloaders with combined reloading experience, we usually get to the bottom of the problems and help other members arrive at resolution.

Will I always post the correct solutions to posted problems? Heck no, especially with each passing year as brain function and memory recall declines. But as long as my eyes can see and my fingers allow me to type, I will continue to "try" to help other members' posted problems.

BTW, your comments on bullet setback with reduction in OAL that could potentially increase chamber pressures over published max and using larger shot group size instead of 5 shot groups was very good. So good that I was actually driven to PM you with praise.

(PM to fxvr5) "Good posts about shot group sample size and bullet setback.

Very good posts about larger sample size when accuracy testing and dangerous effects of bullet setback.

I think many reloaders/shooters approach accuracy testing with limited 5 shot groups which I found to not represent a true picture of accuracy from larger shot groups and larger sample size which you have posted in the past.

Also, very good reminder of effects of bullet setback. Whenever I post on load development, especially new reloaders, I try to add bullet setback testing as part of their QC check."
​

Those posts were very informative and would undoubtedly help anyone reading them. And that's what THR is all about, members helping other members.

So let's focus on helping other members.

OP, sorry for the thread drift.

 

[rfwobbly]

Will I always post the correct solutions to posted problems? Heck no, especially with each passing year as brain function and memory recall declines. But as long as my eyes can see and my fingers allow me to type, I will continue to "try" to help other members' posted problems.

That's exactly the correct mindset to acquire and use.

No, but what matters is that they took the time to help the OP perhaps troubleshoot or look for another cause but together as a "community" of reloaders with combined reloading experience, we usually get to the bottom of the problems and help other members arrive at resolution.

Allow me to point out that without the "attitude" expressed in the above statement, there will be ZERO "community". True "community" is when people ignore individual interests, and pull together. Otherwise the outcome takes on political overtones, and is ultimately determined by who shouts the loudest or most eloquently... regardless of any truth in the content.

Just my 2 cents.
.

 

[mmb617]

Now I wonder what my S&W M&P45 barrel's throat is. I'll have to check it. My S&W M&P9s have short throats and require bullets to be seated very deep to plunk and spin.

Without getting into any arguments I'm curious as to what OAL's you are finding work best for you with those Smith's.

I only have one .45 and it's an M&P Compact. I was having some feed problems when I first got it but after some experimenting everything is good now. With FMJ RN bullets I'm using 1.20 for OAL and need to run them through a light taper crimp to pass the plunk test. I just measured a few and at the case mouth they are .471.

I have two 9mm M&P's, a Compact and a Shield. They both work well at 1.125 OAL with FMJ RN bullets. I've never needed to do any crimping on them. They measure .375 at the case mouth.

 

[fxvr5]

Without getting into any arguments I'm curious as to what OAL's you are finding work best for you with those Smith's.

I only have one .45 and it's an M&P Compact. I was having some feed problems when I first got it but after some experimenting everything is good now. With FMJ RN bullets I'm using 1.20 for OAL and need to run them through a light taper crimp to pass the plunk test. I just measured a few and at the case mouth they are .471.

I have two 9mm M&P's, a Compact and a Shield. They both work well at 1.125 OAL with FMJ RN bullets. I've never needed to do any crimping on them. They measure .375 at the case mouth.

I've only shot a few handloads in the M&P45, old stuff I had sitting around and don't recall any specifics about it. I've not worked on new handloads for that gun yet, so I can't offer any information there. Sorry. I've had no feeding problems with it, yet, but I haven't shot it that much. But thanks for the heads-up on that.

With the M&P9s, the OAL depends on the specific bullet and the exact shape of the nose. Like you, I have to test each bullet to see what will fit. The lengths are noticeably shorter than what my other 9mm pistols require. Most round nose bullets will work at reasonable OALs, but some flat nose bullets have to be seated to just over 1.000" to fit. For example, a Sierra 125 grain JHP just barely fits at 1.023" in one barrel.

 

[Cannibul]

Different bullets require different seating depths.

There are several different profile 230 gr FMJ bullets out there.

You can't compare a reload to a factory round unless you are 100% sure they are using the EXACT SAME bullet.

It's a common new and sometimes not so new reloader mistake.

 

[mdi]

Crimp was not the issue here, even though nearly everyone thought it was.

I see post editing. Can't have the self-proclaimed experts showing misjudgment. Yet, the remaining text is just as damning. Keep editing!

In most cases where newer reloaders are having plunking problems, maybe 85%, the problem comes from crimping, and second by not understanding bullet shape vs chamber length.

Most of the members here with a lot of experience are not "self proclaimed" but given that status , "expert", by other members who have read past, very informative and correct information given by the person. Normally those that complain about "self proclaimed" members are more often than not "wanna be experts" and "keyboard experts"...

 

[joneb]

what is your measurement of the case right at the case mount? The diameter of the bullet at the case mouth doesn't mean anything?

If you are seating and over crimping in the same step this could deform the bullet profile, and change the diameter of the bullet in front of the case mouth.