March 29th, 2019

Inspect Your Fired Brass to Avoid Catastrophic Case Failures

Glen Zediker reloaders corner midsouth book AR-16 reloading semi-auto brass safety primer resizing
Close-up view of a sectioned case. This one here was “fixin’ to pop”, says Glen Zediker.

Here are highlights from an article Glen Zediker wrote for the Midsouth Blog. In this article Glen focuses on cartridge brass. Glen discusses the most common failures that appear with brass that has been shot multiple times, or which has been fired at excessive pressures. Glen explains some simple ways to check your cartridge brass to detect “early warning signs” of case failure, particularly case head separation, which can be dangerous.

Glen is the author of many excellent books on reloading. This article is adapted from Glen’s books, Handloading For Competition and Top-Grade Ammo, available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com.

Handloading for Competition
by Glen Zediker

The Competitive AR-15
by Glen Zediker

Top-Grade Ammo
by Glen Zediker

How Cases Degrade with Multiple Firings By Glen Zediker
This article explains when, and then how, to check after the progress of changes commencing with the firing on a new case. It’s the “progress of degeneration,” in a way of looking at it because the concern is getting a handle on when enough change in the brass has come about to require attention. Or abandonment. As said then, for me that’s 4 firings. That, as said last time, is when I might see changes that need attention. Also as said, that figure didn’t come out of a hat, but from my own notes in running my competition NRA High Power Rifle loads. [Editor’s Note: With Lapua brass, using moderate loads, in bolt-action rifles, we typically get about 10 good (match-worthy) firings. But if you anneal your Lapua brass, and run modest pressures, Lapua brass can perform well for 20 or more load cycles.]

The areas most affected are the case neck and case head area. Case neck walls get thicker [but] the case head area body walls get thinner. Primer pockets get shallower and larger diameter.

Glen Zediker reloaders corner midsouth book AR-16 reloading semi-auto brass safety primer resizing

This case shows a cracked neck AND a crack (separation) above the case head. Zediker says it is “rare to see one case with both of the most common failures. [This case] was attacked by an M14.”

Case Head — Causes of Separation and Cracking
When a case is under pressure during firing, the brass, like water, flows where it can, where it’s more free to move. Of course, the chamber steel limits the amount it can expand. The case shoulder blows fully forward and the case base is slammed back against the bolt face. There is, therefore and in effect, a tug on both ends — it gets stretched. The shoulder area is relatively free to expand to conform to the chamber, but the other end, the case head area, is not. Since that’s the area of the case with the thickest walls, it doesn’t expand “out” much at all. What it does is stretch. The “case head area,” as I refer to it here, is the portion of the case above the web, which is just above the taper that leads in to the extractor groove. The “area” extends approximately an eighth-inch up the case body.

Glen Zediker reloaders corner midsouth book AR-16 reloading semi-auto brass safety primer resizing

Here’s a “pressure ring.” You’ll see this after firing, if you see it. And, if you see it, that case is done. The bright ring indicates excessive stretching, which indicates excessive thinning. If you see a ring circling the case, noticeable because it’s lighter color than the case body, and it’s in this area, I’d say that case is done. And that’s right where a “head separation” occurs. It can crack and also blow slap in two, and that’s the “separation” part of case head separation.

Case-head case cartridge pressure ring separation head failure GS Arizona
Photo courtesy GS Arizona.

This is a spot to keep close watch on as cases age. It is also the area that is more “protected” by sizing with less case shoulder set-back. That is, pretty much, where the freedom for the stretching movement in this area comes from (the case shoulder creates a gap). If you’re seeing a sign that a head separation [might happen with relatively few firings], chances are the shoulder set-back is excessive, and also… the load pressure level.

Bent Paper Clip Case-Wall Gauge
Case-Head Separation paper clip Glen Zediker GS Arizona

Editor: You can use a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. GS Arizona explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case.” Photo by GS Arizona.

Monitor Primer Pocket Dimensional Changes
Another case-head-area and pressure-related check is the primer pocket. As said, the primer pocket will get larger in diameter and shallower in depth each firing. As with many such things, the questions are “when” and “how much,” and the main thing, “how much?”

If the pocket gets excessively shallow, and that’s judged by a primer that seats fully but isn’t at least a tick below flush with the case base, there could be function issues. There’s a risk of a “slam-fire” with a semi-auto that uses a floating firing pin, and, if there is actual protrusion, that has the same effect as insufficient headspace. A primer pocket uniformer can reset the depth of a shallowed primer pocket to what it should be, but the real test for me is how easily the next primer seats into it. If it’s significantly less resistance, I’ll say that case is done. Shallower can be refurbished. That’s a primary function of a primer pocket uniformer. Larger diameter, though, can’t be fixed. I’ve mentioned in another article or two that, any more at least, my main gauge of load pressure has become how much primer pocket expansion there’s been.

AR15 Glen Zediker Practical AR-15 book newGlen’s books, Handloading For Competition and Top-Grade Ammo, are available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com

Glen’s newest book, America’s Gun: The Practical AR15. Check it out HERE!

Permalink - Articles, Bullets, Brass, Ammo, Reloading, Tech Tip No Comments »
October 22nd, 2018

Incipient Case-Head Separation — How to Detect the Problem

cartridge case separation

We are re-publishing this article at the request of Forum members who found the information very valuable. If you haven’t read this Safety Tip before, take a moment to learn how you can inspect your fired brass to determine if there may be a potential for case separation. A case separation can be dangerous, potentially causing serious injury.

cartridge case separationOn the respected Riflemans’ Journal blog there was an excellent article about Cartridge Case-Head Separation. In this important article, Journal Editor GS Arizona examined the causes of this serious problem and explained the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.

The photo below shows a case sectioned so that you can see where the case wall becomes thinner near the web. You can see a little arrow into the soot inside the case pointing to the thinned area. This case hadn’t split yet, but it most likely would do so after one or two more firings.

cartridge case separation

Paper Clip Hack for Detecting Problems
The article provided a great, easy tip for detecting potential problems. You can use a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. GS Arizona explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case. If you do this every time you reload, on at least 15% of your cases, you’ll develop a good feel for what the thin spot feels like and how it gets worse as the case is reloaded more times. And if you’re loading the night before a match and feel pressured for time — don’t skip this step!”

Permalink Bullets, Brass, Ammo, Reloading 2 Comments »
October 27th, 2016

What Is Your Favorite Item of Reloading Equipment?

Sierra Bullets Reloading Equipment Bulletsmiths RCBS rock Chucker single stage press
This article originally appeared in the Sierra Bullets Blog.

We asked a few Sierra Bullets bulletsmiths “What is your favorite ‘don’t know how you ever lived without it’ piece of reloading equipment?” Along with the not-so-surprising “reloading press” responses, there are some interesting answers, including a reloading room, an annealing machine, a comparator, and a home-made tool for detecting incipient case head separation. Check out all the answers below. We would love to hear from you too, please share your response in the comments below.

What Is Your Favorite Piece of Reloading Equipment?

Ballistic Technician Carroll Pilant answered: “Dillon 550 and 650 presses.”

Ballistic Technician Rich Machholz answered: “My universal decapping die is as handy as a pocket on a shirt.”

Ballistic Technician Philip Mahin answered: “A comparator gauge to measure from the base of a case to the ogive of the bullet. This bypasses the tip of the bullet, so I can repeat the same seating depth the next time I visit a specific combination.”

Ballistic Technician Duane Siercks answered: “I don’t know that you would actually call this equipment, but the item that comes to mind would be my reloading room. I had always had to squeeze everything into a corner or even an unheated shed. After we bought our current house, I built a garage and placed it so that I had a window looking down a 250-yard range. I built a dedicated room with heat and A/C. It contains my reloading bench and a shooting bench. The shooting bench lets me slide open the window and shoot down the range. It is very handy to not have to load everything up to go to the range. It also makes load development a lot simpler and efficient. I don’t know how I ever got along without it.”

Ballistic Technician Paul Box answered: “The Lee hand priming tool.”

Former Ballistic Technician Robert Treece answered “My homemade dental pick. I use it to check incipient case-head separations. We all see the ‘bright ring’ down close to the case head, that’s natural, but after several firings could be starting to split apart. You could start by just straightening out a paper clip; flattening one end; sharpening and turning it 90 degrees, then bend if about 1/8″ long will even fit all the way down into .204″ cases. On the other end, bend about 3/4″ to 90 degrees also, in the same direction as the pick. That will give you a handle and also ‘points’” in the direction of the pick as you scrape along the side wall from down inside at the bottom upward along the side wall. If the pick hooks into a crevice — DON’T TRY TO SIZE THE CASE. It will pull apart in your die.”

Chief Ballistician Tommy Todd answered: “A brass annealing machine.”

Production Toolsetter Brad Vansell answered: “Redding Ultramag single-stage reloading press for my rifle and my Dillon 650 for my pistol loading.”

Process Engineer David Palm answered: “Homemade case lube.”

RCBS rock Chucker single stage pressPlant Engineer Darren Leskiw answered: “Beyond the normal equipment, I’d say my electronic scale. Using the beam balance for the past 9 years was ok, but nowhere as easy as using an electronic scale.”

There were many votes for the classic RCBS Rock Chucker single-stage press:

Ballistician Gary Prisendorf answered “RCBS Rockchucker Press, it’s built like a tank, and it will last me a lifetime.”

Production Manager Chris Hatfield answered: “RCBS single stage reloading press.”

Maintenance & Machine Shop Lead Craig Westermier answered: “RCBS Rock Chucker.”

Production Resource Manager Dan Mahnken answered “RCBS Rock Chucker! Buy one and it lasts a lifetime.”

Permalink Reloading 6 Comments »
September 4th, 2015

Safety Tip: Inspect Brass to Minimize Case-Head Separation Risk

cartridge case separation

We are re-publishing this article at the request of Forum members who told us the information proved very valuable. If you haven’t read this Safety Tip before, take a moment to learn how you can inspect your fired brass to determine if there may be a potential for case separation. A case separation can be dangerous, potentially causing serious injury.

cartridge case separationOn the older Riflemans’ Journal blog, GS Arizona wrote an excellent article about cartridge Case-Head Separation. We strongly recommend that you read this article. It examines the causes of this serious problem and he explains the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.

The photo at the top of this article shows a case sectioned so that you can see where the case wall becomes thinner near the web. German scribed a little arrow into the soot inside the case pointing to the thinned area. This case hadn’t split yet, but it most likely would do so after one or two more firings.

One great tip offered involves using a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. The author explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case. If you do this every time you reload, on at least 15% of your cases, you’ll develop a good feel for what the thin spot feels like and how it gets worse as the case is reloaded more times. And if you’re loading the night before a match and feel pressured for time — don’t skip this step!”

cartridge case separation

Permalink News, Reloading, Tech Tip 2 Comments »
December 19th, 2013

Case-Head Separation — Spot Problems Before Things Go Boom…

cartridge case separationOn his Riflemans’ Journal blog, German Salazar wrote an excellent article about cartridge Case-Head Separation. We strongly recommend that you read this article. German examines the causes of this serious problem and he explains the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.

The photo below shows a case sectioned so that you can see where the case wall becomes thinner near the web. German scribed a little arrow into the soot inside the case pointing to the thinned area. This case hadn’t split yet, but it most likely would do so after one or two more firings.

cartridge case separation

One great tip offered by German Salazar involves using a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. German explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case. If you do this every time you reload, on at least 15% of your cases, you’ll develop a good feel for what the thin spot feels like and how it gets worse as the case is reloaded more times. And if you’re loading the night before a match and feel pressured for time — don’t skip this step!”

cartridge case separation

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January 1st, 2013

Case-Head Separation: Causes and How to Spot Problems

cartridge case separationOn his Riflemans’ Journal blog, German Salazar wrote an excellent article about cartridge Case-Head Separation. We strongly recommend that you read this article. German examines the causes of this serious problem and he explains the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.

The photo below shows a case sectioned so that you can see where the case wall becomes thinner near the web. German scribed a little arrow into the soot inside the case pointing to the thinned area. This case hadn’t split yet, but it most likely would do so after one or two more firings.

cartridge case separation

One great tip offered by German Salazar involves using a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. German explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case. If you do this every time you reload, on at least 15% of your cases, you’ll develop a good feel for what the thin spot feels like and how it gets worse as the case is reloaded more times. And if you’re loading the night before a match and feel pressured for time — don’t skip this step!”

cartridge case separation

Permalink - Articles, Bullets, Brass, Ammo, Reloading 15 Comments »