January 04, 2011
The "educated finger" is the reloader's best tool for sensing defects in
A friend suggested the title for this column should read, "The Reloader Versus The Ammo Factory," but that would be wrong. We're not at war. On the contrary, what each does has been influenced by the other.
The Big Difference
We may as well start with the major difference: where the ammo is used. The handloader typially assembles cartridges that need to fit and function in only one or two firearms. Those firearms are right there to make fit-checking easy. The ammo factory has to ship large quantities of ammo that must fit and function in every standard firearm chambered for that cartridge, and it must do so with complete safety and reliability over a wide range of environmental conditions.
"Standard" means firearms built to the voluntary standards of the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) and its European counterpart, the Commission Internationale Permanente (CIP). The primary reason these organizations exist is to pro-vide dimensional and pressure standards so a firearm maker will know that his design will safely accept member companies' ammo and so an ammo maker knows his product will safely function in members' firearms. All dimensions have a maximum and a minimum value.
The standards for ammo have minimum values set to be the smallest dimensions that will safely function. Likewise, firearm chambers are more often than not set nearer the maximum dimension standard. This ensures the "one size fits all" model of factory ammunition but is anything but custom-fitted. The moderate to advanced reloader can fine-tune fit issues to his firearm and, in the process, truly has custom-fitted ammo. A big factory lacks this luxury.
The big factory will either make its cases or get them from a trusted vendor, so case preparation is in the case-making process. The factory will specify materials and dimensions based on the machines that will turn those cases into loaded cartridges. The resulting cases are ready for the first loading stage with no further preparation.
The reloader may be starting with fired cases, possibly some that were fired in more than one gun. Getting consistent results means the hobbyist will spend time making these cases as uniform as possible before the process continues.
This could be trimming, sorting, and most importantly, inspection. A pre-loading inspection station is part of commercial reloading too. In mass production, a case that is out of spec may stop the machines, so a pre-load station may check for dimensional consistency, splits, or things like missing flash holes. Today, this commercial inspection is likely to be digital camera imaging, possibly combined with laser measurements--pretty slick when you consider how many cases we longtime reloaders have checked by hand. The reloader must be as diligent in case inspection. Getting rid of the "problem children" before loading starts makes sense no matter who you are.
For safety in handling thousands of primers, the factory will usually prime cases off-line, commonly in isolation cells for safety. It's common for priming to be done hours or days before loading to give the lacquer primer sealant time to dry. Reloaders can also prime ahead for later loading. I usually prime separately to avoid handling primers with greasy fingers. I guess other people do this too; the reloading equipment companies sure sell a lot of hand-priming tools and other "off-press" priming gadgets. If you prime ahead for later loading, be sure to label the container so there is no doubt what primer type you inserted.
Always take time to visually inspect every case for consistent charging before seating bullets.
The factory is going to inspect again after primer seating. A high, inverted, or tipped primer is trouble on commercial equipment just as it is for the home handloader. Again, the trend is toward digital imaging that compares the priming job to images of a known good primer.
For the average hobbyist, the old "educated finger" across the head of the case is still the best inspection. With a little practice, those primer defects that expensive digital inspection gear detects are easily sensed by feel. It's slower, but it's a key step to quality reloads.
All mass-produced ammunition holds a metered powder charge. Period. Mass production and individual weighing are mutually exclusive. To make up for this need, people who design commercial loaders put extra work into the metering systems. The factory may select the propellant to use based on the propellant's metering qualities. Too coarse a granulation can mean inconsistent charge weights; too fine a granule means some may slip between the metering surfaces and jam the sliding elements.
It's common for factories to have meters with fixed-volume inserts. This is parallel to the powder-bar inserts in a shotshell press. When a load was initially developed in the lab, the engineers selected the propellant and charge that met the performance requirement of the load. That becomes the "nominal charge weight," basically a starting point.
Actual charge weigh is determined at the time of loading. The press is set up with the fixed-volume insert that matches the nominal weight, and the operator loads a small amount of ammo at that setting. The sample is sent to the ballistics lab for pressure and velocity testing. Within a short time, word comes back to the set-up worker so he knows whether to increase or decrease the insert volume.
The hobby reloader might go through a similar process if he's metering propellant. Let's say you noted the numerical powder measure setting last time you loaded. That's like the factory's nominal. You are ready to load that charge again but have a different propellant lot. You will set the meter to the old reading and throw some charges. Weighing them will tell you if you need to adjust for the new lot. The only difference is that you are checking weight instead of pressure and velocity.
A typical factory will have three types of pressure/velocity testing. Set-up testing is as described above; it ensures that the machine starts loading correctly. In-process testing is how the operators make sure the press settings don't drift as loading proceeds. The third is final acceptance testing; it retests a blended sample of cartridges taken throughout the loading run to be final arbiter of "ship" or "scra
A key technology in commercial propellant charging is--no surprise--inspection. Loading machines are fitted with very reliable powder-level detectors that alert the operators to an over-charge, an under-charge, or a missing charge. These are very complex and expensive, but the factories make them a major player in their quality systems.
You, too, better be inspecting your charging operation every time you load. If you are loading single-stage, never seat bullets until all cases have been checked for a consistent charge volume. The old "charge-seat-charge-seat" sequence is, in my opinion, a recipe for trouble. It's too easy to get interrupted and miss a step.
Put all the charged cases in a loading block and shine a bright light in them. In addition to seeing a missing charge, you're comparing powder levels to other cases like the big guys, something where "check-seat" fails. There are powder-checking devices for progressive loaders, too. Learn to use them if you have automated your loading operation.
We can learn from the pros here as well. Their need to meet specifications for overall length is more critical than yours because their product must fit a large number of guns.
In a high-speed loading operation, avoiding the compressed charge is one way to maintain consistent overall length. If a bullet is seated in a very full case, the propellant can push up with enough force to shove the bullet out, increasing the overall length. This can happen before the cases get to the next step. Thus, the big factory will look for ways to reduce or eliminate this rebound effect. It may mean finding another propellant that doesn't require compression. It can also mean designing clever gadgets into the loading equipment that can settle the propellant between charging and seating.
The hobby reloader can struggle with this as well. It is more likely to cause problems in progressive loading equipment. In single-stage loading, we can alter how we meter or pour propellant to reduce its volume in the case; we seldom get that opportunity on our progressive equipment. For progressive reloading, it's best for the hobbyist to select a propellant that doesn't go "crunch" when you seat the bullet.
Big factories crimp just about everything. It goes back to the first point I discussed: The ammo has to work in thousands of different firearms. The only exceptions are some match loads and cartridges that must headspace on the case mouth.
When my crime-lab job allowed me to visit ammunition factories, I realized that just about all the big guys separated the seating and crimping operations. Again, it's an issue of control. When you are pushing on the bullet and the case mouth at the same time, you can produce variations.
Taking a cue from the big boys, I have pretty well separated these functions in my loading. Part of it is because I tend to load older cartridges whose cases have thin walls (e.g., .32-20 and .44-40). The crimping stage can easily crumple thin-wall cases under the best conditions, and simultaneous seating/crimping is not the best condition. However, I find myself doing separate crimping on just about everything I load that needs a crimp. Yes, it's slower, but I like the consistency I get. After all, I'm not a big factory trying to load pallets of cartridges a day.
After everything is assembled, the factory sends samples back to Quality Assurance (QA). QA does more than the standard firing tests. They will visually inspect and measure a representative sample of the loaded ammo lot to make sure it is within specification.
The hobbyist should be making one more check, too. As I box the ammo, I give each one a quick look for dents, cocked bullets, deformed crimps--anything that might have slipped through checks at other stages. I place five to 10 cartridges at a time on a light-colored cloth and roll them a little so I can see the entire case. I also run that educated finger over the primer one more time because so many reloading problems are traceable to bad primer seating.
What Did The Big Guys Learn?
I see two key areas where I believe major ammo makers learned something from hobby reloaders. The first is rifle bullet quality. Twenty-five years ago, you found premium hunting and match bullets only in handloads. Factory ammo had the "generic" bullet--no Nosler Partitions, Trophy Bonded, Speer Grand Slams, or Sierra MatchKings. About the time I moved to Idaho, I started seeing better grade bullets show up in factory ammo. Some were the same premium bullets reloaders buy; others were higher grade bullets the ammo companies developed in-house.
I also saw an improvement in accuracy. We routinely bought samples of most new ammo types and fired them for evaluation. In the late 1980s, we saw the too-common 3-MOA group of traditional factory ammo drop closer to 1 MOA. I will always believe that handloaders drove this trend to better bullet quality and selection.
The other area is propellant selection. In the old days, factories tried to get as many different loads as possible from the fewest propellant types. This allowed better pricing from the powder companies and reduced costs associated with inventory and handling. Today, I see factories willing to inventory a broader selection of propellants. This means that instead of developing a good load, they can make a great load, just like the handloader, with a decent selection of propellants.
There is no one versus the other conflict here. In the future, I hope that we continue to see the reloader and the big ammo factory learn from each other.