Reloading Basics -  Seating Bullets

Bullet seating is the final stage in reloading ammunition, and it is every bit as important as any of the steps before it. It dictates how concentric your ammunition is and the all-important cartridge overall length (COL), two factors that have a huge effect on its performance.
There are various bullet seating dies available, and while most do the job well enough, a specific type of die can sometimes better suit a particular bullet design and significantly enhance its performance.

Bullet seating stems
The seating stem is the part of the die that comes into contact with the nose of the bullet and pushes it into the case’s mouth. The fit between the bullet and the stem is critical because a poor fit can damage the tip of the bullet and may also cause it to be seated in a non-concentric manner. A damaged bullet that is not concentric in the case is not going to perform at its best, and grouping and accuracy will be significantly impacted.
Modern projectiles, like Hornady’s ELD-X (Extra Low Drag) bullets, have heat-shield tips made from a special polymer to improve performance, but the tip mustn’t be damaged during the seating process. This is why Hornady also manufactures specialised ELD-X seating stems designed to engage the bullet further back on the ogive, away from the tip, ensuring they can be seated without damage.
L.E. Wilson supplies its seating dies with a standard seating stem but also offers a more specialised optional stem for very low drag (VLD) bullets.
Not all bullets require such a specialised seating stem to seat correctly, but other die manufacturers also supply alternative seating stems, and it is well worth experimenting to ensure you have the best fit for your bullets.

Die adjustment
With COL being so critical, it is important to be able to adjust it easily and precisely and to be able to lock the die securely in place once it is set correctly, to stop it drifting out of position. All bullet seating dies are adjustable, and most have the facility to lock the die at the desired COL, but if you have a die that does not lock once set, you should mark the die body and the seating stem adjuster and regularly check that the marks remain lined up. Alternatively, you can apply a piece of tape to the die body and the adjuster to stop it from moving.
Bullet seating dies with markings on the adjuster are much easier to use, as the scale allows precise changes to the COL. When marked in 0.001” increments, you can lengthen or shorten your rounds with great accuracy, and if you record the setting for each bullet you reload, it becomes very easy to switch between different cartridge lengths.

Types of die
Bullet seating dies generally all perform the task in the same way, sitting in the reloading press and pushing the bullet into the case when the ram is raised. Some bullet seating dies can be adjusted so that they also apply a crimp to the neck of the case to increase its grip on the bullet, but with correctly resized rifle cases, this is not generally required. If you do need to apply a crimp, then this is best done with a specific die after the bullet has been seated.
Standard bullet seating dies tend to be basic and often lack micrometre adjustment, but they do still produce consistent COLs. Match-grade bullet seating dies usually include extra features, like the micrometre adjustment scale, and they produce more consistent ammunition.
Hornady’s match-grade dies also have features like a floating in-line sleeve designed to optimise bullet alignment and reduce bullet run-out. By aligning the case mouth with the bullet shank, these dies eliminate the risk of bullets entering the die at an angle and failing to seat correctly in the case mouth.
L. E. Wilson manufactures a stainless-steel bullet seater with micrometre adjustment that takes seating to another level. Unlike most other dies, L. E. Wilson’s bullet seater is used in conjunction with an arbor press, a hand-operated tool designed to apply a crushing force to various tasks like riveting or installing bearings. The reloading-specific tools can be expensive, but a very simple homemade version using a reversible clamp works just as well and saves a lot of money.
These dies have two levels of adjustment. When setting the COL, the major adjustment seating cap is first screwed up and down to get the approximate desired length, with one full turn giving 0.042” of adjustment. Minor adjustments of just 0.001” can then be made on the main body of the die using the very clear scale engraved on it. Once set, both adjustments are locked in place with grub screws.
A primed and charged case is placed onto a base plate that has a hole in the centre to prevent the primer from being subject to any contact or pressure, and a bullet is then placed loosely into the mouth of the case. The bullet seating die is then placed over the bullet/case, and the whole arrangement is placed under the arbor press (or clamp). As you apply pressure through the adjuster cap on the top of the die, the bullet is seated into the case.

Conclusion
Just like the other stages of reloading, there is a range of different gear available, each offering its own benefits and, of course, varying prices. The more precise, match grade and highly engineered bullet seating dies do help to produce more consistent ammunition, and those with clearly marked scales make adjusting the COL much quicker and easier, though they also tend to be more expensive.
I load .308 Winchester ammunition using a variety of equipment, ranging from the standard Lee Precision die to the L. E. Wilson stainless steel bullet seater and the Hornady match grade die. They all produce good ammunition, but with the more expensive ones, the precision and consistency of the ammunition are noticeably better. The best option is to go for the best that you can afford. GM

Contacts:

 
• Lee Precision – Henry Krank - www.henrykrank.com
 
• Hornady – Edgar Brothers - www.edgarbrothers.com
 
• L. E. Wilson – www.lewilson.com