Comments on: Bullet Concentricity Basics — What You Need to Know

By: Grimstod

Grimstod — Sat, 02 Feb 2019 19:42:57 +0000

Gene I have tried this but it has not yielded better result yet. That said my concentricity is usually better then .001 on my BRX and the dies I have for it. Now my Redding dies are bad. Usually runout is in the .002-4 range. Turning them and completing the seating has not helped. There must be something else a foot.

By: David S

David S — Sat, 02 Feb 2019 17:56:39 +0000

The article shows the Hornady and Sinclair run out checkers. I think the same loaded cartridge measured on both devices will give your two different readings. The reason is they way the cartridge is held, with the Sinclair device showing more run out than the Hornady.

With the Sinclair device the further you move the indicator away from the front support the more run out you will show.

On the Hornady unit the indicator is between the supports.

By: GeneD

GeneD — Fri, 01 Jun 2018 23:25:41 +0000

I’ve taken Mr. Tompkins tip a step further , in that I rotate the round in six to eight incremental steps as I seat my bullets . Apparently it works with my dies , as I seldom have a round more than .0015 out . Most are between .0005 / .0010 . You don’t get in a hurry to shoot , so why be in a hurry to load ?

By: mark

mark — Sun, 07 May 2017 18:04:49 +0000

can non-straight press makes non-straight seated bullet ammo?

i think that brass slide on shellholder (if not too tight put in) in direction that seating die controls, so the direction of the brass and bullet on the top of it is controled with the seating die tightness, and not that non straight press can push the brass non straight into the seating die…?

By: Mikec

Mikec — Sat, 06 May 2017 11:30:33 +0000

James, making straight ammo is nothing like that.

By: james

james — Thu, 27 Oct 2016 15:53:02 +0000

Seating a bullet into a case is much like seating a dowel pin for location. The dowel pin must enter its hole at least 1 1/2 times its diameter to be stable and effective. No special tooling required, other than a ball peen. If you are not, you can easily undo any accuracy you have obtained by poor handling of the rounds afterwards.
Tool and Die 101.

By: Boyd Allen

Boyd Allen — Tue, 03 May 2016 15:32:47 +0000

The most important consideration for producing concentric ammo, after quality brass, are the dies. They need to match the chamber of the rifle that they are used to load for, so that the minimum amount of sizing is done that is consistent with the type of rifle and how it will be used. Obviously this will be different for target bolt actions, hunting rifles, and semiautomatics. One piece sizing dies that over size the neck causing excessive pull as the expander is pulled through are to be avoided at all cost. It is not the expander that is the problem, but rather the ID of the neck part of the die. If your sizing die does not produce relatively straight sized brass, it will have to be replaced, or modified. There is no substitute for a die that produces straight brass. Nothing else can compensate for the accuracy lost by its use.