How do you align rifle bullets in neck when seating?

Is there a scientific...or at least accepted...way of aligning your bullet to the case neck before you pull the press-lever to seat?

In my case, using flat-bottom jacketed bullets in neck sized cases, I find it difficult to "stand up" the bullet on the case mouth. And even more tricky to make sure it's coaxial to the brass.

Your best practice?

Thanks!
Rich

I hold the bullet as it rides up into the die, once it's in the die it will hold it.

Hornady seating dies have a sliding crimp sleeve that helps insure alignment. I like the system a lot. Another option is to flare the neck but this adds to work hardening and potentially reduced grip on the bullet by the neck.

Check out Redding Competition Seating Dies. Little pricey but well worth it for that reason and several others. IMHO

I just set my bullet in the neck where expanded to a step, not a taper, by my Lyman M die. An extra step but worth it to me.

I always cut a slight chamfer in the mouth of my rifle cases. The bullets will then sit straight on them. Of course, with boat tails it's no problem.

I always cut a slight chamfer in the mouth of my rifle cases. The bullets will then sit straight on them. Of course, with boat tails it's no problem.

In addition ot the case-prep quoted above, I free-floated the shellholder in my press to help alignment with the die. I turn the case 90 degrees during seating. Runout with my handloads is usually under .002".

ZM

There are patents on the Gov website, with ingenious methods to keep the bullet straight, but of the commonly available loading equiptment, the sliding sleeve Redding, RCBS, or Forster [all Forster seater dies are sliding sleeve, but their patent has expired, and now anyone can make them].

But much more important than the seater die, is the case neck straightness before the bullet is seated. Brass that has had an expander ball pulled through the neck may be no good, but if the chamber neck is big enough, the brass may be salvaged by shooting it again.

I have been getting great groups with cheap RCBS dies, and just removing the expander ball. Life without an expander ball is filled with small groups.

WOW! Thanks everyone for the excellent replies. I'm using Redding dies, Neck only resizing and Seating at this time on my 7MM-BR and 300 Win Mag. So it looks like, as long as I keep the bullet relatively straignt onto the seating die, the internals handle the rest.

Now -- what do you mean by an "expander ball" -- the part on my size die that's above the decapping pin?

Why shouldn't it be used...what's the theory?

Happy Thanksgiving!
Rich

Anything big and bulging on the stem above the de capping pin is an expander ball. These days, they are getting long and tapered.

If you pay $80 for a Sinlcair concentricity checker + dial indicator cost, you will get a short set of instructions that say, "the problem will probably be the exapander ball". Then the $80 instrument goes on the shelf. Save yourself $80 and remove the expander ball.

If the expander ball goes in the neck when it is big from being fired, and then the neck portion of the sizing die follows, then withdrawing the expander ball through the smaller neck means that the sizer ball is changing the neck diameter with no alignment, and the case is being pulled buy the shell holder which pulls more on the backside. This bends the neck by an amount the cannot be seen with the naked eye, but can be detected with a concentricity gauge or by shooting groups. The eccentricity of .004" will case 2" bigger groups, but any more eccentricity is straightened out by the chamber.

Most talk about accuracy is black magic, but the relationship between twist rate, ammo concentricity, and accuracy is mathematically derivable and verifiable.

When the bullet enters the bore, it enters crooked. That makes the center or rotational momentum off the center of the bore. When the bullet exits the muzzle, it veers off in the direction of it's center of momentum. The ratio of the velocity to revolutions per minute of spin determine how far the point of impact will be from the point of aim. This is directly proportional to the twist rate. Because the chamber forces concentricity to within ~ .004", the error is typically only +/- 1" at 100 yards = an extra 2" to the group. Twice the twist rate would make that 4".

The way the accuracy game is played is to get a twist rate fast enough to stabilize the length of bullet to be used, but no faster.

"The NRA Handloader's Guide" 1969, a compilation from "The American Rifleman" 1950 to 1968, article gauging bullet tilt, by A.A. Abbatiello and was based on "The Bullet's Flight" by Dr F.W. Mann and the work of George L. Jacobson of the Frankford Arsenal in 1959:
"Mathematical Solution
The laterally displaced center of gravity moves though the bore in a helical (screw) path. The pitch of this helix is the pitch of the rifling, and the radius is the lateral displacement of the center of gravity. On leaving the muzzle the center of gravity continues in the direction it had at that point. .. The angle of emergence is that angle who's tangent is 2pi times the lateral displacement times the pitch. For a .004" displacement and a 10" rifling pitch, the tangent is 1/8 (2 pi)(.004) / 10 and the corresponding angle is 1.1 minutes.
...The effects which Jacobson found.. are essentially in agreement with the work reported here."

If one must use an expander ball because the bullet can not get started into the neck [and I have never seen this with rifles] then expand only the mouth of the neck and do it in a separate push stroke, not pulling.

--
Be careful what you pray for, it can happen.

The Lee collet dies don't use an expander ball - they use a straight rod sized to the bore diameter. Evidently, the rod helps ensure that the neck sizing collet can't collapse the case neck if the die isn't adjusted properly. The fact that it's a rod (instead of a ball) seems to keep things lined up.

I've been able to detect no difference in group size when I neck size with or without the expander rod in a Lee collet die.