The custom-designed priming machine processes over 10,000 cases per hour.

The custom-designed priming machine processes over 10,000 cases per hour.

When you’re manufacturing self-defense ammunition, you have to be perfect. You never know when the performance of one single round might mean the difference between life and death.

Not too long ago, Sig Sauer, the company that adopted the phrase “to hell and back,” got into the ammunition business in a big way. Hiring the best engineering team they could find, they launched a massive R&D program to design ammunition to their exacting standards. Once designs for new V-Crown projectiles were perfected, they went about not only buying, but also designing and building custom equipment to produce the best ammunition they could.

Recently, I had the pleasure of touring their Eubank, Kentucky, facility. Located in farm country about an hour and a half from Lexington and two and a half from Nashville, this first facility had what they needed to get the business off the ground. After construction of an extra building and installation of millions of dollars worth of additional equipment, they were ready to go.

The process of making ammunition is fascinating to me, but one thing stood out during my tour. The folks who work there are indeed finicky and persnickety — again, in a good way. These people literally stay up late at night devising ingenious new techniques and machines to measure, double-check and triple-check their process. While I can’t share all the details, I will point out some of the ways they build redundant validation and verification into their manufacturing.

I spent most of a day with Dan Powers, who has been running the Sig Sauer Ammunition division for the past two and a half years. Jason Imhoff, ammunition engineer, BJ Rogers, plant manager, and John Ervin, quality engineer, joined us.

These guys are passionate about ammunition. Watching them light up as they consider a new idea about how to improve the quality of production was like watching me gawk at tens of thousands of rounds of 300 Blackout ammo on the shop floor that day.

Let’s walk through the process, start to finish.

It all starts with the brass cartridge cases. Sig has these made to their specifications. To make sure that none of the millions that arrive are out of spec, their supplier runs each and every cartridge case through a laser inspection machine that checks all critical dimensions.

This tool checks 210 cases at a time before loading.

This tool checks 210 cases at a time before loading.

Next comes priming, and as a reloader, I had to stop and marvel at the speed and precision of the process. Cartridge cases are fed from one pallet-sized crate into a rotary priming machine that first checks dimension and depth of the primer pocket. Primers are pushed into place, then the machine checks again to make sure that a primer is actually present and seated to the correct depth. The exit spout was spitting out primed pistol cases about as fast as I could pull a trigger. The quantity and speed are mind-boggling. Each machine can prime over 10,000 cases per hour.

Once the brass is inspected and primed and projectiles are ready to load, it’s time to assemble brass, powder and projectile into a complete cartridge. Sig Sauer uses the plate loading technique. Rather than running cartridges through the loading process single file, entire trays of 210 cartridges go through each loading step as a group. Special plates are designed for each caliber and built to exacting tolerances.

The first step is to get the cartridge cases into the plates. Giant shaker bed machines vibrate the plates as cartridge cases are heaped on top. The heavier weight of the base encourages them to settle into the correct orientation into the plate. Before cases are prepped for powder and projectile insertion, they’re checked yet again.

Top-secret custom-designed machines check overall case length and once again check the primer flash hole. Remember, that’s already been checked earlier, but redundancy rules here. Plant manager BJ Rogers explained to me why there is extra attention on the primer flash hole. If it’s malformed, or not present, the pressure of ignition will lock up a gun, putting it out of action. For self-defense ammunition, failure like this is not an option.

The first production step is belling the cases. For pistol projectiles with flat bases, the case mouth is expanded ever so slightly to allow insertion of a bullet without deforming the bullet or the case mouth. For rifle rounds, like the subsonic 300 Blackout I saw in production, there is no need to expand the case mouth. The “belling” step serves as an extra check to make sure the open case mouth is perfectly round. Remember, this step is performed all at once on the entire plate of 210 rounds.

Next up is powder charging. This is another super-secret and proprietary method. What I can say is that custom-designed machinery charges all 210 cartridges with exact powder measures within ridiculously tight tolerances. I’ve verified this by chronographing velocities of the finished product. There is very little variance from one round to the next.

The bullet seating step starts with more shaking of custom-designed plates that hold the projectiles. As with the cartridge cases, most bullets will fall into position in the plates in the correct orientation due to the heavier base. While I was there, the team was loading 220-grain subsonic 300 Blackout projectiles. As these have a center of gravity square in the middle of the extra-long bullet, filling took a little extra encouragement by hand to make sure all were seated correctly. At this point, we’re working with two sets of trays, one with powder-filled cartridge cases and the other filled with projectiles.

Sig-Sauer-Ammunition-Tour.jpg Optical scanning equipment can instantly record every critical dimension of parts of finished cartridges.

Sig-Sauer-Ammunition-Tour.jpg Optical scanning equipment can instantly record every critical dimension of parts of finished cartridges.

Bullet seating comes next. The two trays, one with cases and the other with bullets, are brought together and bullets are pressed into the open cases to exactly the right depth. At this stage, lengths of the cases have been checked and rechecked multiple times. Here, the overall length of the assembled cartridge is verified.

The crimping step is next, where each case mouth is pressed back into original dimensions after insertion of the bullet. It’s at this point that the loading plates serve as a convenient batch-checking reminder. One round from each tray is set aside for additional inspection and test firing. Super sophisticated optical scanning checks critical dimensions of the assembled cartridge. Other guinea pig samples are baked and frozen before test firing. Pressures of heated cartridges are monitored to make sure high-temperature environments don’t create dangerous over-pressure situations. On the opposite extreme, chilled cartridges need to produce enough pressure to cycle reliably the actions of semi-automatic guns.

One of the luxuries of building a brand new ammo production facility is that you can take advantage of the latest automation technology. Sig Sauer has even done this for the process of getting completed cartridges into the plastic tray inserts you find inside each box of ammunition. A sound-insulated room has more vibration machines with special feeding plates. The open funnels over each hole in this plate guide bullets into the plastic packaging trays. This is a really noisy place, as you might imagine. As trays are filled, they exit the room on a conveyor belt to the machinery that mesmerized me the most.

That would be the packaging machine. I know, here I am in a plant filled with ammo in various states of production, and I stop and gawk at the packaging machine. It’s kind of miraculous, though.

As 20- and 50-round trays enter one end, robotic octopus arms with suction cups grab flattened boxes and begin the process of opening the cardboard container and lining it up with the ammo tray. Push rods gently insert the cartridges into the box, and then the real magic happens.

A tray of cartridge cases ready for powder charging.

A tray of cartridge cases ready for powder charging.

Guides, ramps and pushers somehow manage to close that little cardboard flap on the box perfectly every time. I can’t even do that by hand. It was flawless. I’m sure the Sig folks considered me a total dork for being so interested in this part.

Next on this line, labels are applied for the specific ammo variety, bullet weight and specifications. Last but not least is final packaging into larger case-sized boxes for shipment.

What stood out to me was the incredible attention to detail. These folks are picky, picky, picky. I lost count of the number of times that dimensions, fit and weight are checked. When I spent some time testing ammunition with quality engineer John Ervin, I understood why.

Ervin’s job is to obsess over all the details. Remember those rounds pulled from each plate for testing? That’s one of the things Ervin checks himself. Each lot of ammunition is tested and logged in exacting detail. Pressure, accuracy, temperature conditions and more are recorded and compared against expected performance.

These shakers are setting 220-grain 300 Blackout projectiles in trays for seating and crimping.

These shakers are setting 220-grain 300 Blackout projectiles in trays for seating and crimping.

Even the process of making ballistic gel is thoroughly documented. Each gelatin block (and they go through a lot) is mixed with exact weights of gel and water. The lot number of gelatin used is even recorded. It cools for exactly 45 minutes and is then stored in a 38-degree cooler for no more than three days.

When shot with various FBI protocol tests, it’s immediately discarded. Recycle gel blocks? Not a chance of that happening here.

I’ve tested Sig Sauer ammo with great result. After seeing the level of care that goes into production, I’ll carry it in my guns.

[This article originally appeared in Shooting Sports Retailer magazine.]