Bullet seating?

M

muslmutt

Guest
Ok, I checked the concentricity of my brass just prior to loading, it was good. Even though bullets were seated carefully using standard RCBS dies some of the loaded bullets were significantly more concentric than others? What happened? Uneven case necks that were thick on one side?
Thanks.
Matt.
 
You don't say what caliber or dies you used, but you are probably using standard dies with the expander ball near the bottom of the decapping pin. What happens is that the die sizes the neck way smaller than what is necessary to hold the bullet. Then on the downstroke of the press, after the neck is completely clear of any support by the die, the neck is pulled over the expander ball. if the brass is thinner on one side or softer on one side, most of the expansion will occur on the thin/soft side and the neck will be pulled out of concentricity. Seating the bullet will move the neck a few more thou and there you go. You have bullets that are visibly off center.

Try a Lee collet die or a bushing sizing die and you will be amazed how much more concentric your ammo is. Using a straight line seater on crooked cases ain't gonna get you very far.
 
I checked the cases on a Sinclair concentricity gauge just prior to loading. They were sized, trimmed etc... and pretty straight.
I tried this with 221 Fireball, and 25-06.
I will look at those dies. I was aware they existed but never really priced them.
Thanks.
Matt.
 
Riflemiester,

Can this problem be minimized by removing primers in one stage and then neck sizing in a separate stage?
 
I see no advantage to decapping and neck sizing as separate steps. I have seen gains in concentricity by running the case through the sizing die with the expander ball removed and then expanding over a mandrel as a separate step. However, the collet die is probably the most cost effective method of really loading superior ammo. Also, the collet die is relieved in the shoulder area and will resize the Ackley improved cartridges without buying the expensive special dies. As most cartridge cases have some taper in neck thickness from the shoulder to the mouth, I generally go with Lee collet dies for my non neck turned cases and bushing dies with my neck turned cases. Good luck.
 
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