When it is time to seat bullets, you may need to accomplish slightly more than just seating a bullet. You need to make sure if there was any bell in the cases (to aid in the seating process) that it is removed as well as adding any crimp that you feel is needed for the finished rounds.
Hornady Dies
You are going to need an appropriate die or dies, calipers to measure cartridge overall length (COAL)-hopefully, you wrote down the intended COAL with your load data. If you bought a complete caliber die set, you likely have seating die. Lee sets separate seating and crimp die; however, some brands come with seating die that can also perform a taper crimp. You need to decide if you intend to crimp. Unless there is a cannelure on the bullet, I do not plan on crimping. I have yet to find a situation where a crimp has made my rounds more accurate, so long as I have enough neck tension being provided by the brass sizing die. Your mileage may vary.
Caliper and COAL gauge
Follow your die manufacturer’s instructions for setting up your bullet seating die. You may want to back out the seating stem; if so insert a case with a bullet on it that you have validated has an appropriate amount of powder. Raise the ram of the press, screw the seating stem down until it touches the bullet, lower the ram, and add two or three turns so that you can start seating the bullet. You are just trying to seat it far enough to get an initial measurement without the bullet falling out of the case. Continue to adjust the seating stem until you achieve the desired COAL and tighten the lock nut if applicable.
If you load the same round frequently, you may want to consider making a dummy round. To create one, seat a bullet in a case that has been sized (clearly labeled so you do not mistake it for something that it is not), and it will help you set your die up much faster next time.
Many seating dies have changeable stems, useful if you find the seating die you are using leaves marks on your bullets. Standard vs. VLD (very low drag) style seating stems may work better or worse depending on the bullet and seating stem combination you intend to use. As long as you are not observing any damage to the jackets as you seat the bullets, your stem is probably fine. If you see rings or any deformation of the jacket, you may want to consider a different seating stem if your die offers that option.
If you accidentally seat a bullet too far, you can use tools to make the cartridge a little longer, or even remove it completely. If you only have one or two cartridges to disassemble the impact bullet pullers are sufficient. If you have a lot of cartridges to disassemble, you may want to look at something like the Hornady collet style bullet puller. The Hornady bullet puller uses your press to quickly disassemble rounds, though I am sure it will leave marks on the bullets as you pull them out.
If you decide to crimp, do it after the seating process is complete with a tool like the Lee Factory Crimp die. Other dies that utilize a taper crimp style die; follow the direction with your specific die.
For a comprehensive overview on bullet seating and bullet seating depth, be sure to watch the video above!
–Bolt Action Reloading
For the complete 4-part article, see Reloading’s Beginner’s Guide – How to Start Reloading