Creedmoor Sports is a leading vendor of products for competitive shooters and serious hand-loaders. Along with great gear, Creedmoor Sports provides informative content for its customers. The Creedmoor InfoZone provides Reloading Tips, Gear Reviews, Shooting News, and basic gunsmithing information.
Bill Gravatt, President of Creedmoor Sports, is an expert on reloading processes and gear. He developed many of the popular tools marketed by Sinclair Int’l, and he brings that expertise to Creedmoor Sports. Bill hosts a series of “how-to” videos produced for the Creedmoor InfoZone.
In this video, Bill Gravatt demonstrates several methods to clean your cases. Bill tells us: “Powder residue should be removed before you insert your cases into your reloading dies. There are several ways to clean your cases. Many shooters use a combination of various methods…”
1. Manual Cleaning — You can use 0000 Steel wool for the outside of the case and a Case Neck brush for the inside. A paper towel can remove any remaining residue. This is a handy way to clean if you load at the range.
2. Vibratory Tumbling — This traditional method works well, particularly for pistol brass. Experiment with both Corn Cob and Walnut media. You can get a brighter shine by putting a small amount of liquid brass polish in the media.
3. Wet Tumbling with Stainless Media — This process can get your brass clean inside and out. Do check to ensure no pins are stuck in the flash-holes. Watch for peening of case mouths that can occur over time.
4. Ultrasonic Cleaning — Ultrasonic cleaning works great for small parts as well as brass. The ultrasonic process removes all carbon and traces of lube, which can leave the inside of case necks too dry. To smooth bullet seating, try putting a tablespoon of Ballistol in the cleaning solution.
Cleaning Reloading Dies
Cleaning your reloading dies is something that many hand-loaders neglect. In this 60-second Tech Tip, Bill Gravatt provides some smart advice on cleaning your dies. Bill notes: “After heavy use, case lube and carbon can build up in your reloading dies. It’s important to keep them clean. Also, with new dies, give them a good cleaning before first use, because they ship with a corrosion inhibitor.”
1. Step 1 — Prior to cleaning, disassemble the die and spray it with a good degreaser. Do this with brand new dies too.
2. Step 2 – Take a patch and run it in the die to remove old lube and gunk. Don’t forget the decapping assembly and other internal parts.
3. Step 3 — After cleaning the die, but before reassembly, spray the die with a good corrosion inhibitor, such as Corrosion-X or Starrett M1.
There’s a nice article in the Western Powders Blog that any varminter will enjoy. In this hare-raising tale, gunwriter Jim Waddell explains how he used a self-loading Savage A17 rifle to take care of a serious jack rabbit problem on a rancho in California. “[My friends] purchased a huge amount of acreage that had some existing alfalfa fields and [surrounding sagebrush]. Sagebrush is home to jack rabbits. Lots of jack rabbits. The previous owner of this property didn’t do any varmint or predator control[.] The ink wasn’t dry on the escrow papers before [my friends] started asking for help shooting rabbits. A problem in taking these critters is it has to be done at night when they come out to feed as they lay low in the bush during the daylight hours.”
Savage A17 Comes to the Rescue
Initially Waddell and some friends took on the jack rabbit hordes using Ruger 10/22s and a .44 Magnum Marlin lever gun. Neither option was ideal. The .44 Magnum just couldn’t keep up the desired shooting pace (it took too long to reload) ant the .22 LRs were too anemic. So Waddell decided to give the more potent 17 HMR a try. He acquired a Savage A17 and went back for a second bunny-busting session. He came away convinced that the 17 HMR cartridge in the semi-auto Savage works great for small varmint control.
NOTE: This is in an older internet archive so it may take a minute or so to load.
Waddell writes: “I wanted more than a .22 after seeing the problems my pals had with their [10/22] bullets not anchoring the rabbits. Armed with my new Savage A17 it was time to head back to the alfalfa fields. This time my hunting partner was Dan, my son-in-law from Seattle. We hunted for four nights. Each night was either raining, windy or both. My question about whether or not rabbits would be out in the weather was answered immediately. They were everywhere. As miserable as the weather was, we got all the shooting we wanted and that Savage rifle was up to the task. We got so many rabbits it was impossible to count.” CLICK HERE for the full account of Waddell’s jack rabbit adventures on the California rancho. It’s worth a read. Here is a sample:
Wabbits, Wabbits Everywhere — Even Running Right at You
I couldn’t believe my eyes when I saw a sea of rabbits as far as the lights would shine and when the light beams hit the bunnies, they became confused and as often as not, would run right at the lights so a good percentage of our shots were literally in spitting distance. It was also a new experience shooting at targets that are running TOWARD you. Most of us who’ve done much hunting for game or varmints have experienced moving targets but how many of those targets are coming at you?
Sources for Best Deals on 17 HMR Ammunition
With 17 HMR ammunition it definitely pays to shop around. This spring (March 2026) we’ve found a 50-count box of 17 HMR ammo as low as $10.10 and as high as $19.99. A typical price currently is about $13.99-$16.99, as you’ll see at Midsouth. You can check multiple vendors’ 17 HMR ammo prices at once on the AmmoSeek.com and BulkCheapAmmo.com websites. Here are some of the best deals we found on 3/10/2026 on BulkCheapammo.com starting at $10.10 per 50-rd box:
Here’s an inexpensive procedure that can help you load straighter ammo, with slightly better measured concentricity (i.e. less run-out) on the case necks and bullets. Simply use a Rubber O-Ring on the underside of the die locking ring. This allows the die to self-align itself (slightly) to the case that is being sized. Without the O-Ring, if the flat surface on the top of your press is not perfectly square with the thread axis, your die can end up slightly off-angle. This happens when the bottom of the locking ring butts up tight against the top of the press. The O-Ring allows the die to float slightly, and that may, in turn, reduce the amount of run-out induced during case sizing.
Top prone shooter GSArizona, who sadly passed in 2022, tried this trick and said it works: “Go to your local hardware store and get a #17 O-Ring (that’s the designation at Ace Hardware, don’t know if its universal). Slip the O-Ring on the die and re-adjust the lock ring so that the O-Ring is slightly compressed when the die is at the correct height. Size and measure a few more cases. You will probably see a slight improvement in neck concentricity as the die can now float a bit as the case enters and leaves it. This isn’t going to be a dramatic improvement, but it’s a positive one.”
We want to stress that adding O-Rings to sizing dies may help some reloaders, but we don’t offer this as a panacea. Try it — if using the O-Ring reduces measured runout that’s great. If it doesn’t, you’ve only spent a few pennies to experiment.
Lee Precision makes die lock rings with built-in O-Rings. Lee’s distinctive lock ring design allows the same kind of self-alignment, which is good. However, Lee lock rings don’t clamp in place on the die threads, so they can move when you insert or remove the dies — and that can throw off your die setting slightly. By using an O-Ring under a conventional die lock ring (that can be locked in place), you get the advantages of the Lee design, without the risk of the lock ring moving.
Among AccurateShooter’s most-visited web pages have been powder relative burn rate reference guides ranking powders from fastest to slowest. Here is the latest version of the Powder Burn Rate Table. Compiled by Hodgdon Powder Co., this Burn Rate Chart displays the relative burn rates of 176 different powders. Shown below is the latest table, released by Hodgdon in July 2024.
You’ll want to download this Powder Burn Rate Chart PDF. This 176-entry comparison table provides vital information for hand-loaders — with tested burn-rates. Note — this invaluable chart is not limited to Hodgdon and IMR propellants. This burn rate chart includes powders from eight major powder-makers: Accurate, Alliant, Hodgdon, IMR, Norma, Ramshot (Western), Vihtavuori, and Winchester.
This chart (July 2024 version) provides useful information for all hand-loaders. When doing load development, and testing one powder versus another, it’s generally wise to choose propellants that share the same relative burn rate, as least for starters.
NOTE: Hodgdon powders are red, IMR powders are yellow, Winchester powders are blue, Accurate powders are gray, and Ramshot powders are orange. Powders from Alliant, Norma, and Vihtavuori appear on the chart with white background. DOWNLOAD Burn Rate Chart HERE as PDF.
We are finally seeing prices drop on loaded ammo, and there are some notable inventories of ammunition right now at Midsouth, Palmetto State Armory, Powder Valley and Precision Reloading. We are even starting to see ample supplies of large-caliber hunting rifle ammunition — something hard to find a year ago.
Thankfully, if you shop around aggressively, you can now find many types of ammunition at reasonable prices. By using AmmoSeek.com you can instantly compare ammo prices from dozens of sellers. AmmoSeek monitors more than 180 online vendors — checking current pricing and available inventory, for pistol, rifle, and shotgun ammunition. Looking for .22 LR ammo for your rimfire trainer or .45 acp ammo for your 1911? Just select the cartridge type from the “Quick Seek” list on the right. Likewise you can find .223 Rem and .308 Win Rifle ammo with one click.
If you haven’t sourced ammo online before, note that, for nearly all jurisdictions, it IS legal to order ammunition online and have it delivered to you at home in most states. But check your state and local laws! California, for example, has prohibited direct ammo shipments to ordinary customers.
Got Ammo? Here’s just part of the vast inventory at Skagit Arms in Washington State.
Use Ammoseek.com to Find Reloading Components Too
Ammoseek.com also lets you search for reloading components, including powder, primers, brass, and bullets. This is a huge time-saver. You can instantly check a dozen or more vendors to see if a particular type of powder is in stock. Likewise, you can quickly check for primer availability. If you have a big match coming up and are short on primers — this could solve the problem. To search for components, from the AmmoSeek home page, click the gray “Reloading” Tab (see below), then select Bullets, Brass, Primers, or Powder from the pull-down menu.
AmmoSeek.com FAQ Page
If you have questions about using AmmoSeek.com, visit the AmmoSeek FAQ Page. You’ll find details on how the search engine works. Here’s one FAQ:
How often does the AmmoSeek engine process its ammunition data?
Every minute or two! AmmoSeek is constantly updating ammunition data 24 hours a day, 7 days a week, automatically. Individual retailers are updated at least hourly, most most are updated much more often. Still, however, there’s always the possibility that items can go out of stock the moment after our site is updated, so it’s not always possible to be 100% accurate.
Photo 1: Three Near-Equal-Weight 7mm Bullets with Different Shapes
TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).
This article, from the USAMU Facebook Page, concerns reloading safety. In the relentless quest for more speed and flatter ballistics, some hand-loaders load way too hot, running charges that exceed safe pressure levels. Hint: If you need a mallet to open your bolt, chances are your load is too hot. Stay within safe margins — your equipment will last longer, and you won’t risk an injury caused by over-pressure. In this article, the USAMU explains that you need to account for bullet shape, diameter, and bearing surface when working up a load. Don’t assume that a load which is safe for one bullet will be safe for another even if both bullets are exactly the same weight.
How Bullet Profile and Bearing Surface Affect Pressure Levels
Today, we continue our handloading safety theme, focusing on not inadvertently exceeding the boundaries of known, safe data. Bullet manufacturers’ loading manuals often display three, four, or more similar-weight bullets grouped together with one set of load recipes. The manufacturer has tested these bullets and developed safe data for that group. However, seeing data in this format can tempt loaders — especially new ones — to think that ALL bullets of a given weight and caliber can interchangeably use the same load data. Actually, not so much.
The researchers ensure their data is safe with the bullet yielding the highest pressure. Thus, all others in that group should produce equal or less pressure, and they are safe using this data.
However, bullet designs include many variables such as different bearing surface lengths, hardness, and even slight variations in diameter. In fact, diameters can occasionally range up to 0.001″ by design. Thus, choosing untested bullets of the same weight and caliber, and using them with data not developed for them can yield excess pressures.
This is only one of the countless reasons not to begin at or very near the highest pressure loads during load development. Always begin at the starting load and look for pressure signs as one increases powder charges.
Bullet Bearing Surface and Pressure
Bullet bearing surface length (BSL) is often overlooked when considering maximum safe powder charges and pressures. In Photo 1, note the differences in the bullets’ appearance. All three are 7 mm, and their maximum weight difference is just five grains. Yet, the traditional round nose, flat base design on the left appears to have much more BSL than the sleeker match bullets. All things being equal, based on appearance, the RN/FB bullet seems likely to reach maximum pressure with significantly less powder than the other two designs.
TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).
Bullet 1 (L-R), the RN/FB, has a very slight taper and only reaches its full diameter (0.284 inch) very near the cannelure. This taper is often seen on similar bullets; it helps reduce pressures with good accuracy. The calculated BSL of Bullet 1 was ~0.324″. The BSL of Bullet 2, in the center, was ~0.430″, and Bullet 3’s was ~ 0.463″. Obviously, bullets can be visually deceiving as to BSL!
Some might be tempted to use a bullet ogive comparator (or two) to measure bullets’ true BSL for comparison’s sake. Unfortunately, comparators don’t typically measure maximum bullet diameter and this approach can be deluding.
Note: Due to time constraints, the writer used an approximate, direct measurement approach to assess the bullets’ different BSLs. While fairly repeatable, the results were far from ballistics engineer-grade. Still, they are adequate for this example.
Photo 2: The Perils of Measuring Bearing Surface Length with Comparators
In Photo 2, two 7mm comparators have been installed on a dial caliper in an attempt to measure BSL. Using this approach, the BSLs differed sharply from the original [measurements]. The comparator-measured Bullet 1 BSL was 0.694” vs. 0.324” (original), Bullet 2 was 0.601” (comparator) vs. 0.430” (original), and Bullet 3 (shown in Photo 2) was 0.602” (comparator) vs. 0.463” (original). [Editor’s comment — Note the very large difference for Bullet 1, masking the fact that the true full diameter on this bullet starts very far back. You can use comparators on calipers, but be aware that this method may give you deceptive reading — we’ve seen variances just by reversing the comparators on the calipers, because the comparators, typically, are not perfectly round, nor are they machined to precision tolerances.]
Thanks to the U.S. Army Marksmanship Unit for allowing the reprint of this article.
Tumblers and walnut/corncob media are old school. These days many shooters prefer processing brass rapidly with an ultrasonic cleaning machine. When used with the proper solution, a good ultrasonic cleaning machine can quickly remove remove dust, carbon, oil, and powder residue from your cartridge brass. The ultrasonic process will clean the inside of the cases, and even the primer pockets. Tumbling works well too, but for really dirty brass, ultrasonic cleaning may be a wise choice.
Our friend Gavin Gear has evaluated an RCBS Ultrasonic cleaning machine using RCBS Ultrasonic Case Cleaning Solution (RCBS #87058). To provide a real challenge, Gavin used some very dull and greasy milsurp brass: “I bought a huge lot of military once-fired 7.52x51mm brass (fired in a machine gun) that I’ve been slowly prepping for my DPMS LR-308B AR-10 style rifle. Some of this brass was fully prepped (sized/de-primed, trimmed, case mouths chamfered, primer pockets reamed) but it was gunked up with lube and looking dingy.”
UltimateReloader.com Case Cleaning Video (7.5 minutes):
Gavin describes the cleaning exercise step-by-step on UltimateReloader.com. Read Gavin’s Cartridge Cleaning Article to learn how he mixed the solution, activated the heater, and cycled the machine for 30 minutes. As you can see in the video above, the results were impressive. If you have never cleaned brass with ultrasound before, you should definitely watch Gavin’s 7.5-minute video — it provides many useful tips and shows the cleaning operation in progress from start to finish.
Ultra Dry Necks After Ultrasonic Cleaning — Some Suggestions
The Ultrasonic cleaning process gets cartridge brass so “squeaky clean” that increased force may be required to seat your bullets, or they may “grab” as they go in the necks. To reduce bullet-seating effort, you may benefit from adding a little dry case lube inside the case-neck before loading (use a nylon brush). Another trick is adding a teaspoon of Ballistol lube to the cleaning solution. That provides a trace lubricant inside the necks, but does not interfere with powder ignition in any way.
The latest Gen2 RCBS ultrasonic cleaning machine has a large 6.3-quart capacity. That’s nearly 100% larger than the first generation machine in Gavin’s video. The bigger Gen2 machine, $419.99 at Precision Reloading (with FREE shipping), features a second ceramic heater and transducer to better clean brass cases and firearm parts. The LED is easily programmable, and the timer can be set for up to 30 minutes of cleaning. The original 3.2 quart-capacity RCBS ultrasonic machine, as shown in Gavin’s video, is still available for $197.99 at Midsouth Shooters. There is also another good 6-liter multi-mode ultrasonic cleaning machine, with stainless steel tank, available for $199.99 on Amazon.
At the request of our readers, we provide select “Deals of the Week”. Every Sunday afternoon or Monday morning we offer our Best Bargain selections. Here are some of the best deals on firearms, hardware, reloading components, optics, and shooting accessories. Be aware that sale prices are subject to change, and once clearance inventory is sold, it’s gone for good. You snooze you lose.
NOTE: All listed products are for sale to persons 18 years of age or older. No products are intended for use by minors.
Brownells — Match Ammunition Sale, Major Brands, Many Types
⏺️ » Big savings on match ammo from Berger, Federal, Hornady and more
This week Brownells is running a major sale on top-tier Match Rifle Ammunition. You can save 10-25% on high-quality ammo for .223 Rem, 6mmGT, 6mm Creedmoor, 6.5 Creedmoor, .308 Win, .300 Win Mag, .30-06 Springfield and more. Brands on sale include Berger, Federal, Fiocchi, Hornady, and SIG Sauer. If you need factory ammo for an upcoming match or want to use it to test a new rifle, this is a good opportunity.
MidwayUSA — Major Athlon Optics Sale, Save up to 53%
⏺️ » Major discounts on wide selection of Athlon scopes and more
Athlon makes a variety of high-quality products, including rifle scopes, spotting scopes, thermal scopes, rangefinders, radar chronographs, and binoculars. Right now at MidwayUSA you can get discounts up to 53% on a large selection of quality Athlon products.
As an Amazon affiliate, this site can earn revenues through sales commissions.
With the catastrophic fires last year in California, many have wondered about hazards faced by gun owners in fire zones. This important video shows what really happens when loaded ammunition burns. You will probably be surprised. Contrary to Hollywood notions, the ammo doesn’t ignite in a massive explosion. Far from it… basically the rounds “cook off” one by one, and the bullets release at relatively low velocity. We’ve featured this SAAMI research project before, but it is worth reprising for those who have not yet seen the burn tests.
A few years back, SAAMI released an important video concerning ammo and fire. With professional fire-fighters standing by, over 400,000 rounds of ammo were incinerated in a series of eye-opening tests. If you haven’t had the chance to view this video yet, you should take the time to watch it now
The Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) has produced an amazing 25-minute video that shows what actually happens to sporting ammunition involved in a fire. This video shows the results of serious tests conducted with the assistance of professional fire crews. We strongly recommend you watch this video, all the way through. It dispels many myths, while demonstrating what really happens when ammunition is burned, dropped, or crushed.
Watch SAAMI Ammunition Testing Video
Video Timeline
2:10 Impact Test (ignited outside firearm)
3:40 65-foot Drop Test
5:08 Bullet Impact (.308 Win firing)
7:55 Blasting Cap Attacks
9:55 Bulldozer and Forklift Tests
12:20 Boxed Ammo Bonfire
15:37 Bonfire without Packaging
17:21 Retail Store Simulation Burn
20:55 Truck Trailer Burn
Over 400,000 rounds of ammunition were used in the tests. Some of the footage is quite remarkable. Testers built a bonfire with 28,000 rounds of boxed ammo soaked in diesel fuel. Then the testers loaded five pallets of ammo (250,000 rounds) in the back of a semi-truck, and torched it all using wood and paper fire-starting materials doused with diesel fuel.
The video shows that, when ammo boxes are set on fire, and ammunition does discharge, the bullet normally exits at low speed and low pressure. SAAMI states: “Smokeless powders must be confined to propel a projectile at high velocity. When not in a firearm, projectile velocities are extremely low.” At distances of 10 meters, bullets launched from “cooked-off” ammo would not penetrate the normal “turn-out gear” worn by fire-fighters.
We are not suggesting you disregard the risks of ammo “cooking off” in a fire, but you will learn the realities of the situation by watching the video. There are some amazing demonstrations — including a simulated retail store fire with 115,000 rounds of ammo in boxes. As cartridges cook off, it sounds like a battery of machine-guns, but projectiles did not penetrate the “store” walls, or even two layers of sheet-rock. The fire crew puts out the “store fire” easily in under 20 seconds, just using water.
Additional Testing: Drop Test, Projectile Test, Crush Test, Blasting Cap Test
Drop Test
The video also offers interesting ammo-handling tests. Boxes of ammo were dropped from a height of 65 feet. Only a tiny fraction of the cartridges discharged, and there was no chain-fire. SAAMI concludes: “When dropped from extreme heights (65 feet), sporting ammunition is unlikely to ignite. If a cartridge ignites, it does not propagate.”
Rifle Fire Test
SAAMI’s testers even tried to blow up boxes of ammunition with rifle fire. Boxes of loaded ammo were shot with .308 Win rounds from 65 yards. The video includes fascinating slow-motion footage showing rounds penetrating boxes of rifle cartridges, pistol ammo, and shotgun shells. Individual cartridges that were penetrated were destroyed, but adjacent cartridges suffered little damage, other than some powder leakage. SAAMI observed: “Most of the ammunition did not ignite. When a cartridge did ignite, there was no chain reaction.”
Bulldozer Crush Test
The test team also did an amazing “crush-test” using a Bulldozer. First boxes of loaded ammo, then loose piles of ammo, were crushed under the treads of a Bulldozer. A handful of rounds fired off, but again there was no chain-fire, and no large explosion. SAAMI observed: “Even in the most extreme conditions of compression and friction, sporting ammunition is unlikely to ignite. [If it does ignite when crushed] it does not propagate.”
Blasting Cap Test
Perhaps most amazingly, the testers were not able to get ammunition to chain-fire (detonate all at once), even when using blasting caps affixed directly to live primers. In the SAAMI test, a blasting cap was placed on the primer of a round housed in a large box of ammo. One cartridge ignited but the rest of the boxed ammo was relatively undamaged and there was no propagation.
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.
On the highly-respected Riflemans’ Journal blog, created by our late, dear friend German Salazar*, there was an excellent article about Cartridge Case-Head Separation. In this important article, Salazar (aka 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.
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!”
* Sadly, German Salazar passed away unexpectedly on June 21, 2022 at age 62. German was a great inspiration to this site who helped guide the creation of the AccurateShooter Forum. A brilliant man, expert attorney, and top-tier marksman, German will be sorely missed in the shooting sports world.
Bullet 1 (L-R), the RN/FB, has a very slight taper and only reaches its full diameter (0.284 inch) very near the cannelure. This taper is often seen on similar bullets; it helps reduce pressures with good accuracy. The calculated BSL of Bullet 1 was ~0.324″. The BSL of Bullet 2, in the center, was ~0.430″, and Bullet 3’s was ~ 0.463″. Obviously, bullets can be visually deceiving as to BSL!
The Sporting Arms and Ammunition Manufacturers’ Institute (
We are not suggesting you disregard the risks of ammo “cooking off” in a fire, but you will learn the realities of the situation by watching the video. There are some amazing demonstrations — including a simulated retail store fire with 115,000 rounds of ammo in boxes. As cartridges cook off, it sounds like a battery of machine-guns, but projectiles did not penetrate the “store” walls, or even two layers of sheet-rock. The fire crew puts out the “store fire” easily in under 20 seconds, just using water.
On the highly-respected Riflemans’ Journal blog, created by our late, dear friend German Salazar*, there was an excellent article about Cartridge Case-Head Separation. In this important article, Salazar (aka 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.
