This guide is a work in progress. For the overview and links to other chapters, click here.
You’ve resized and primed the case, dropped the powder charge, and now it’s time to seat the bullet.
Here we come to the real meat of reloading. Here we see how form and function interact.
You might be chasing better accuracy or consistency, or cost savings, or whatever excuse you’ve sold to yourself and your friends and family.
But ultimately the bullet is the thing you’re going to fling downrange, and it’s going to have a purpose and an intended effect – you need to keep this in mind as you undertake this step in the reloading process.
In the simplest sense, bullet seating pushes the bullet into the neck of the case, slightly expanding the case neck’s diameter and creating the necessary tension to hold the bullet in place. If you’ve been following along through this guide, you properly determined how to set the correct tension already, and you deburred and chamfered the case mouth.
If you didn’t do that, you’re likely to see some issues at this stage. You may see bulging or denting in the case mouth. You might crush the case entirely. You might see that the bullet seats in a way that isn’t concentric to the exterior of the case neck or case body.
All of these issues can be resolved with proper case preparation. In some cases, you might need to lubricate the inside of the case neck (or the base of the bullet). This will be discussed further in the chapter on advanced reloading.
Bullet Selection
You need to ask yourself what you want this bullet to do when it gets to the target.
Until the advent of smokeless powder, bullets were made with very soft lead that would expand greatly upon reaching the target, creating a large wound cavity as the bullet cut its way through the animal’s flesh.
Smokeless powder allowed shooters to reach much higher velocities, and therefore flatter trajectories in their loads. But the increased pressure created in smokeless powder combustion causes gas to escape around the bullets as they traveled through the barrel, resulting in significant leading of the barrel, and the negative accuracy and barrel-care problems that come with it.
The copper jacket was the solution to this problem. Shooters could once again push the limits of their powder without rapidly copper fouling their barrels. But it didn’t take long for shooters to realize that these harder, copper encased bullets did not expand the same way the older cast lead bullets had, and as a result were not as effective at killing game.
So the soft point bullet was born. The copper around the body of the bullet kept the gases in check, and the soft lead on the tip of the bullet starts the expansion process and exposes the inner lead core on impact.
Today, reloaders have soft point, polymer point, hollow point, open tip match, and other high quality options that allow the shooter to choose the balance between ballistic coefficient, penetration, and expansion.
Thus, you should consider whether your bullet is intended for target training, for peak accuracy, or for lethality on impact, and choose your bullet design accordingly.
Bullet Weight

There are two ways to increase terminal energy: increase velocity through powder volume, or increase bullet weight.
Lighter bullets are generally cheaper, and are often better candidates for target shooting than heavier bullets. But, as velocity has a greater impact on energy than bullet weight, a lighter bullet can help you reach a higher velocity if you need to hit something at a greater distance.
Heavier bullets can be useful if you need to deliberately reduce your muzzle velocity. For example, if you are developing a subsonic load, it will be easier to get under 1125fps with a heavy bullet than with a light one.
Twist Rate
The twist rate on your barrel is a ratio representing the number of inches of travel for your rifling to complete one rotation. Rifling in a 1:10 barrel will complete one rotation in ten inches. As this is a ratio, the smaller the second number, the faster the twist, i.e. a 1:7 twist barrel is faster than a 1:10 twist barrel.
In general, given that you are comparing bullets within the same caliber, minimum twist rate to stabilize a bullet increases as the weight of the bullet increases.
Berger has a very helpful calculator for calculating optimal twist rate for stabilization of your bullet. This calculator uses the Miller formula, which does not work well with bullets with a flat base. Consult the manufacturer’s documentation for your specific bullet.
Seating Depth
Your die can be screwed in or out to change how deep the bullet is seated inside the case neck. There are a few reasons why you might want to change seating depth.
The first is a functionality concern. Your rounds have to fit in your magazine, and you have to be able to chamber them without malfunction. Longer overall length can sometimes create some problems here.
Similarly, a longer overall cartridge length can result in the bullet being jammed into the rifling when chambering. If the cartridge is later removed unfired, it can pull the bullet from the neck, causing powder to spill inside the receiver.
The second is an accuracy concern. The distance from the bullet’s seated position to the point it makes contact with the rifling is called “bullet jump”. Different rifles have varying preferences for bullet seating depth due to variations in throat length and rifling characteristics. By experimenting with different seating depths, you can find the sweet spot that maximizes accuracy in your rifle.
Keep in mind that seating bullets closer to or farther from the rifling can affect chamber pressure. As with any other load variable experimentation, a new load workup is recommended and you should always watch for adverse pressure indicators.
To set up your seating die, you’ll want to raise the ram with your shellholder in place, and screw the die in until the outer die body is contacting the ram. From contact, unscrew the die according to the manufacturer’s specifications (usually a quarter to full turn).
Adjusting the seater plug varies based on die manufacturer, but if you have a factory loaded round, you can get in the ballpark by unscrewing the seating plug, running the loaded round into the die, and then screwing the plug back in until it contacts the bullet.
From there, use your calipers to make any adjustments to cartridge overall length.
Should I Crimp?
This step is sometimes performed simultaneously during the seating process, but can be controlled independently depending on how you setup your die.
If you are finding that your seating die is damaging your brass, you may consider performing this step separately with a crimping die, to avoid damaging the case by seating and crimping at the same time.
In general, rifle ammunition will not require crimping, and neck tension is sufficient to hold the bullet in place.
On those cartridges where crimping is advised, there are two types of crimping. The taper crimp squeezes the brass into the bullet. You’ll find this type of crimp on many modern cartridges like straight wall pistol cartridges or, more rarely, some bottleneck rifle cartridges that will be used in semi-automatic platforms.
The second type of crimp, the roll crimp, is found in straight wall rifle and pistol cartridges designed for lever-action rifles and cartridges designed for revolvers. This die rolls the brass into a groove on the outside of the bullet called the cannelure. This prevents the bullet from moving forward or backward under recoil.
Your manual should give guidance on your particular cartridge’s crimping requirements.
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