Inserting bullets is one of the easier tasks to learn. There are only a couple things you can do wrong, and it is easy to learn how to do them right!
The first area of potential mistake is in not preparing the case mouth correctly to receive the bullet. In the case of pistol cases, this is generally done with an expander die which is a standard component in any three- or four-die set for handgun ammo. The trick here is to learn the correct amount of expansion. Follow the die manufacturer’s instructions and test a couple cases. Too little expansion simply means the bullets can get “caught” on the edge of the case while being inserted. (See “RELOADING/MISTAKES” for some interesting pictures of bullet insertion errors.) This can scrape lead off of lead bullets and actually tear the side off of a brass case with jacketed bullets. Too much expansion simply means the bullet will go further into the case before you raise it into the bullet seating die. The risk here doesn’t deal with the bullet insertion itself, but with the fact that you are work-hardening your case mouth too much when it has to be forced back around the bullet, significantly shortening case life.
Prepping the case mouth for rifle brass is a little different. There is typically no equivalent “expander” die for rifle brass in any die set (although they can be special ordered). Prepping a case mouth for rifle brass consists of using the proper case re-sizing die (collet or full-length) with a properly sized plug in the die. Upon insertion of the case into the die, the neck is sized down below the bullet diameter, and the case mouth is then pulled over the plug as the case is removed, resizing the case mouth to the approximate size of the bullet diameter. There is no expander die. The equivalent step with rifle brass is done with a chamfering tool. This is a little hand-held device that trims the sight edge off one edge of the case mouth (either the inside edge or outside edge) and then the tool is turned over to do the other edge. This tapering of the inside edge of the case mouth is typically all that is needed to start the bullet correctly.
The second mistake people can make is not inserting bullets straight in-line with the case mouth. This should be rather obvious. The more you rush and the sloppier you are placing the bullets on top of the cases for insertion, the more likely you are to get the bullet “cocked” to one side or the other during insertion. And the consequences should be equally obvious. They run anywhere from having bullets slightly off-center which negatively affects accuracy, to again damaging cases and probably he bullets themselves, causing waste.
The primary goal here is to get the bullet started correctly. Once that has occurred, the rest of the bullet seating takes place within the bullet seating die. There are a few variables here, but typically not of concern to the new reloader. The end of the seating mandrel inside that die has a shape to it that is intended to help keep the bullet centered as it is inserted. There are various claims by various manufacturers of dies that the design of their dies and/or the shape of this seating mandrel is “better” on their equipment than the “others.” The implication here is that you’ll somehow damage the tip of the bullet more frequently or more severely with one manufacturer than the other. While I’m sure there are very specialized applications where this may be necessary, I’ve never experienced any damage of any type to any bullets in many, many years reloading many thousands of rounds. And I know people who load and shoot with extreme accuracy who use nothing more than standard dies with standard bullet seating.
One of the other important elements of bullet seating is the bullet seating depth. All manual reloading data will list a measurement most commonly referred to as “C.O.L.” which stands for “Cartridge Overall Length.” This is generally considered the maximum length the finished cartridge should be from the base of the case to the tip of the bullet. This obviously means achieving this overall length would dictate the minimum bullet seating, because seating the bullet further would result in a shorter C.O.L. This is an area that requires clarity for the new reloader, however, because there can be unintended consequences when seating a bullet deeper than the C.O.L. measurement. In some cases (primarily rifle) inserting a bullet deeper does not significantly alter combustion pressures. In other cases, however (primarily pistol), different seating depths can significantly alter combustion pressures. Therefore, the safest rule of thumb is: Always load to the C.O.L. length.
There can be some reasons for deviation from this. The most notable one – and one that is referenced in some of the reloading manuals – is to seat slightly deeper if finished cartridges fail to feed. 1) I have NEVER had a cartridge fail to feed when loaded to the C.O.L. So C.O.L.’s are a pretty reliable depth to seat to! 2) If you do need to seat differently, solicit input from a reliable source, only do it for starting minimum loads, and then remain consistent in the seating depth as you work up the load. But I personally would only alter seating depth as a last resort as a new reloader, and only with input from a very experienced reloader or source. (One great source that is often overlooked are the bullet and powder manufacturers. Call them! They do take customer calls. And they do provide excellent advice. And they have the most to gain – and lose – by having their products miss-used. So they are going to be very safe and very reliable with the information they provide!)
In the case of pistol ammo, if there is a failure to feed, only seat deeper by one- or two-thousandths of an inch at a time, only with minimum loads, and stop immediately when you reach a depth that feeds correctly. But as I said, even though the manuals touch on this possibility, I have never had any of the handgun cartridges I’ve loaded over the years fail to feed or cycle properly at published C.O.L.s.
All of the above notwithstanding, altering seating depth in rifle ammo can have a significant impact on accuracy. But as with all-things-reloading, don’t make any changes without knowing what you are doing and why! See Jason’s excellent article on reloading for accuracy. They cover this and other important issues where possible deviations from beginner practices may be safely learned.
A word about the accuracy with which you seat bullets. Novices aren’t going to know how accurate is accurate. And, given all the cautions about weighing powder to 1/70,000th of a pound, it’s easy to see where the beginner will think they need at least one-thousandth of an inch accuracy in C.O.L., right? After all, C.O.L. is the only measure we have of how deeply the bullet is seated. And for some reason, when you seat 10 bullets in a row with the exact same brass prepped exactly the same way, on the same press with the same bullet seating die and the same bullets, there are several thousandth’s difference from bullet to bullet!
Let’s look for a moment at why you are doing what you are doing, not the “what” itself. Of course you are putting bullets in a case. But why is the C.O.L. so important? Two reasons. One obvious one is feeding. If the bullets are too long, they won’t cycle through a semi-auto or fit in the chamber of a single shot, or a revolver cylinder won’t close. If they are too short, they may not cycle in a semi-auto either.
But what else? The bullet seating is what determines how much space there is in the case for combustion. And if you make that space significantly smaller, you increase the combustion pressure, potentially without realizing it. So there are two important reasons for wanting bullet seating depth to be accurate.
So what affects the accuracy of that seating depth? If you have a good press and you have a good die properly adjusted and secured so that there is no “play” in it when you are seating bullets, the biggest variable is likely to be the bullets themselves. Yes, they are made to exact standards. But then they are placed in bulk in boxes. (Seldom do you see such expensive packaging that each individual bullet would be in a separate pocket like primers are.) They are shipped, stored, handled, dropped… In short, they bang into each other. And the tips are often a polymer softer than the bullet itself. Or the tip is lead and is easily deformed. Or the bullet is all lead and has all sorts of minute nicks and scratches on it. Take 10 random bullets you are loading and measure the bullets precisely with your calibers to one-thousandth of an inch. You will probably be surprised. You’ll find as much variation as you’re finding in your C.O.L.! This is especially problematic with all lead bullets, and the softer the more variation you are likely to find.
So what do you do? Trust your equipment. Make sure your press is solidly mounted, your die properly adjusted and secure. If they are, then seat your bullets while adjusting your dies until you are averaging the correct C.O.L. Now VISUALLY look at the bullets you loaded. The seating depth should be pretty obvious to the naked eye. If they’re loaded to a crimp groove or cannelure, the depth is even easier to see because the bullet depth is in reference to a fixed visual marker on the bullets themselves. Are you happy you’re in the right neighborhood? If you’ve loaded to the book C.O.L., and if you’re using bullets with a cannelure or crimp groove and the bullet mouth is where it’s supposed to be in relation to either, then load the rest of your bullets! As long as they visually are falling in the same place on the cannelure or crimp groove, you can’t be wrong. And think about it… if you were to painstakingly adjust the seating die for every bullet to get every bullet at exactly the same depth to the thousandth of an inch, you haven’t actually made better cartridges! Because those slight variations in bullet length that you measured have now been translated into slightly different seating depths, so the variation has been transferred from where it probably won’t matter (slight variations in C.O.L.) to slight variations in the ignition space inside the cases where it might! The difference shouldn’t create a safety issue, but it might translate into slight differences in accuracy.
Think about it this way … if a properly adjusted progressive press can crank out hundreds of rounds an hour without every primer being hand-inserted, and every bullet being painstakingly seated to the exact seating depth, etc. and that ammo is safe, yours will be too. The primary difference is you still have the ability to put more painstaking accuracy into every round doing them one-at-a-time than a progressive press does. But relax enough to enjoy doing it as well!
Joel Guerin, Versailles, Kentucky