9mm dented rim and Shockbottle case gauge

trav70

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I've just started reloading 9mm on a new Dillon XL650, and run into an issue. Not with the Dillon, but with brass and my case gauge.

As a bit of background, I've been reloading for over 5 years, mostly .308Win on a single stage (hundreds of rounds), over a thousand rounds of .45ACP on a Lee Turret, some .357 Magnum and a few other, but until now I've not bothered to reload any 9mm because I could always find it online for cheap enough. Now that I got a good deal on a XL650, I figured it was time to start doing some 9mm in volume for the coming summer match season. I'm not an expert reloader by any stretch, but I do have at least some idea of the process.

I also have two Shockbottle case gauges - one in .45ACP and one in 9mm. When I reloaded the .45, they all fell easily into the gauge, no issues, and have all worked flawlessly in my various .45's so far.

Today I tried my first run of 10 rounds of 9mm, mostly just to see if I had the Dillon set up properly. Out of the 10 rounds, 3 did not fit well into the case gauge - they protruded slightly, as in the following pic, which shows a "good" one next to a "bad" one:
gauge1.jpg

Profile view:
gauge2.jpg

I checked my resizing die, my expander die, and the final crimper die, and they all seemed set properly, so I looked more closely at what was blocking the perfect fit.

It seemed to be a dent from an extractor, on the rim, that made the rim a bit out of round and slightly protruding in that one spot. On the unaffected cases, the dent was not there, or much fainter. To check for sure, I tried placing the cases in the gauge upside down (or right side up, depending on your perspective - basically, rim end first, bullet up). For the "good fit" ones, the case rim dropped into the gauge holes easily (not all the way in, of course, because the "chamber" of the case gauge is tapered a bit like the round itself, but the whole rim dropped into the top part of the hole). With the "bad fit" rounds, the rim end wouldn't go easily into the top of the gauge hole, it was binding.

Here is my attempt at a photo of the dented rim, which seems to be causing the problem:

rimdent.jpg

When I try the rounds in my barrel (plunk test) they all seem to fit properly, because the rim never makes contact with anything, except presumably some of the area around the breech face, which on my two 9mm pistols seems to have reasonably generous clearances. This also tells me that the rest of the case is properly sized, so it's not an issue with my dies, I believe, unless someone else with more wisdom knows something I'm missing. I don't think resizing dies are supposed to resize/straighten the rim?

"bad" round fits:
bentrim9mm.jpg

"good" round fits the same:
goodrim9mm.jpg


I haven't had a chance to actually take them to the range and try them in the guns, since we still have a decent amount of snow up here, but I hope to try them in the next few weeks.

Has anyone else had any experience with this sort of issue, where the rounds don't fit the case gauge but seem to fit the barrel?
If it was only one or two rounds out of a hundred, I'd just set them aside in a practice pile, but if it's going to be anywhere like 30% of my rounds, that starts getting more annoying.

I guess I'm just wondering if anyone has come across this particular situation with these Shockbottle case gauges, and what the solutions may be, other than reloading 1000 rounds to get 700 "competition" rounds and 300 practice ones.
Or maybe that's the yield percentage I should expect when looking for good, well-functioning rounds for competition use?
I know, the problem isn't with the case gauge, it's with my fired brass :), but I have no easy way to sort them before they're run through the Dillon (because they're not resized until then, and may not fit the case gauge for that reason alone).
I never had this issue with the .45ACP I reloaded, and using the .45 Shockbottle gauge. Of course, different guns, different extractors, different brass etc., I know...

Anybody have a way of measuring rim diameter/concentricity on 1000's of fired 9mm brass quickly and easily?
I guess the solution I'll probably take, is just pull aside all the non-fitting rounds, and then plunk test each of them in the barrel. But the whole reason for getting the 100 round case gauge was to avoid having to do that.

OK, I guess this is less of a question, and more of an expression of my annoyance that the gods of Fired Brass are conspiring to make using my new Dillon XL650 just a little more work :d
 

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It looks like the extractor of whatever that case came out of did that from what I can see in your picture. I picked up some once fired 44 magnum a guy was shooting out of a Desert Eagle and they look exactly like that. The extractor really does a job on them.
 
If you look at the SAAMI case and chamber drawing it gives plus and minus tolerance figures.

And what you are seeing is variations in rim diameter, meaning the larger diameter rims are not dropping all the way into the gauge.

Put the case base first into the case gauge and you will see why it does not drop all the way into the gauge. If the rim fits but the case stops just above the extractor groove you may have a bulged case. BUT since I have had your same problem with 9mm cases I will guess it is larger rim diameter.

The SAAMI rim diameter manufacturing tolerance is .394 - .010 or .394 to .384

And the case body diameter just above the extractor groove is .3910 - .007 or .391 to .384

So you can see the rim at maximum diameter can be .003 larger than case body diameter. And the rim thickness can vary .010 and why you have the ding inside your rim on these thicker rims.

I use range pickup brass and buy bulk once fired brass in 9mm and .40 S&W. And was amazed how hard some 9mm cases were to get through my bulge buster dies. But after measuring the rim diameters it became clear, I was sizing some of the case rims. And the 9mm cases had the most variation in rim diameter and required the most effort in the bulge buster die.

This is why you hear reloaders say the best case gauge is your barrel. I have a Dillon 9mm case gauge and all my cases will drop into this gauge.

BUT my EGW 7 hole 9mm chamber checker is slightly smaller in diameter and some of the cases will not drop all the way into this gauge if I do not run them through my bulge buster.

This does not just apply to pistol cases and the same thing can happen with rifle case gauges.

Below a Wilson, Dillon and JP Enterprise case gauges with .223/5.56 case inserted base first. And as you can see the red JP Enterprise gauge is smaller in diameter and the case does not drop as far into the gauge. And all this means is the JP Enterprise gauge is closer to minimum case diameter than the other two gauges.

KSB3ZvP.jpg


Bottom line, welcome to the world of plus and minus manufacturing tolerances. Your cases are good to go, you just have a tight case gauge that doesn't like fat rims.
 
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Thanks for the responses, folks.

Armored, they are a mix of 90% my brass, 10% range pickups left lying around and grabbed when I was picking up my own brass. It's the rim on them that's wide, not the case bulging above the rim, so I don't think it has anything to do with a Glock bulge.

Reeferman, my initial thoughts were that the aggressive extractor was deforming the rim just enough to make it too wide for the case gauge.

But, after digesting bigedp51's info, I now see it may not necessarily be related to that extractor mark, it may just be some of the cases are wider at the rim, within the limits of acceptable tolerances. When I try and drop them in the gauge rim first, the "bad" ones don't fit, suggesting the gauge is sized on the minimum end of tolerances.
I am going to have a closer look and see if it's related to brand - if one headstamp seems to be wider, then it becomes a bit easier to sort out ahead of time.

However, it seems I may not even need to worry about it - if they fit the gauge, they're a "go" for sure. For the ones that don't fit the case gauge properly, I'll just manually test them all in the barrel, and put them in the "good" pile if they fit the barrel but not the gauge.

This illustrates, to me, one of the pitfalls of acquiring more equipment and taking more measurements. You start to notice little things out of spec that you didn't even know were there before, and it becomes more challenging to figure out which of these newly discovered "defects" are important enough to worry about, and which can be safely ignored within limits. But, that's why I ask for input from those with more knowledge and experience !
 
Thanks for the responses, folks.

Armored, they are a mix of 90% my brass, 10% range pickups left lying around and grabbed when I was picking up my own brass. It's the rim on them that's wide, not the case bulging above the rim, so I don't think it has anything to do with a Glock bulge.

Reeferman, my initial thoughts were that the aggressive extractor was deforming the rim just enough to make it too wide for the case gauge.

But, after digesting bigedp51's info, I now see it may not necessarily be related to that extractor mark, it may just be some of the cases are wider at the rim, within the limits of acceptable tolerances. When I try and drop them in the gauge rim first, the "bad" ones don't fit, suggesting the gauge is sized on the minimum end of tolerances.
I am going to have a closer look and see if it's related to brand - if one headstamp seems to be wider, then it becomes a bit easier to sort out ahead of time.

However, it seems I may not even need to worry about it - if they fit the gauge, they're a "go" for sure. For the ones that don't fit the case gauge properly, I'll just manually test them all in the barrel, and put them in the "good" pile if they fit the barrel but not the gauge.

This illustrates, to me, one of the pitfalls of acquiring more equipment and taking more measurements. You start to notice little things out of spec that you didn't even know were there before, and it becomes more challenging to figure out which of these newly discovered "defects" are important enough to worry about, and which can be safely ignored within limits. But, that's why I ask for input from those with more knowledge and experience !

That sure looked like an aggressive extractor but now looking at it on a full size screen compared to a iPhone maybe not. Learn something new everyday.
 
I have the same issue from time to time in my 40 gauge . Brass is not range pickups but all fired through my pistol. For me it's the extractor mark . I try the "bad" rounds in my dillon gauge since it's a touch looser, but tbh a little bit of sand paper and the burr is gone so it works fine. They all shoot fine out of the pistol.
 
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