bullet concentricity in a loaded cartridge

[tom]

By using a regular seater I can only get about 50% of my bullets under .005" run-out in a loaded cartridge (case neck is around .002"). Short of buying a competition seater, is there anything I can do to improve my odds? Tom

[Cariboo]

If your runout on a sized case neck is .002" then that will be multiplied at the bullet. .

What make of dies are you now using?

Are you FL sizing or neck sizing?

Do you turn your case necks?

What cartridge are you loading for?

What bullet are you using?

[tom]

Originally Posted by Cariboo

If your runout on a sized case neck is .002" then that will be multiplied at the bullet. .

What make of dies are you now using?

Are you FL sizing or neck sizing?

Do you turn your case necks?

What cartridge are you loading for?

What bullet are you using?

Hi Cariboo,
I am using either RCBS or redding dies. I full length size all my cases. I do not turn my case necks. I load many cartridges from 22-250 to 45-70. My run of the mill bullets are Hornady interlock. The culprit is in the regular seater die which doesn't alignment the bullet with the case perfectly.
I do get 30-40% of my ammo. under .003". I get a much higher percentage with my 308 benchrest seater. I am trying to see if there is something I can do with my regular seater to improve my odds.
Incidentally all the ammo. with greater than .005" run-out shoots pretty well the same as the 'good' ones. Fred Sinclair from Sinclair International said anything up to .004" is acceptable in the bench-rest world. Therefore I wonder what the largest run-out would be before it starts to open up the group in a hunting world.
Anyway in the spirit of pursuing perfection, I have ordered more competition dies from Sinclair. I figure they are good investments anyway.
Thank you for your help. Tom

[Cariboo]

Hi Tom

I can usually get pretty good rounds, <.005" run-out, using standard Redding , RCBS, and Hornady dies. When resizing the cases I always make sure the inside of the necks are lubed so that the expander plug pulls out with equal resistance and doesn't pull the neck out of square. With RCBS and Redding dies I also will leave the decapping rod slightly loose in the die so it is able to centre in the neck while it is withdrawn.

Before seating the bullet I start by making sure that the case mouth has a good chamfer on the inside. Once the bullet is started in the case about 1/2 way I will back off on the press handle and rotate the case 180* and finish seating the bullet. I also am anal about making sure the case is fully seated in the shell-holder as I have found that if the case is the least little amount of out-of-square with the ram bullet run out is sure to occur.

[tom]

Originally Posted by Cariboo

Hi Tom

I can usually get pretty good rounds, <.005" run-out, using standard Redding , RCBS, and Hornady dies. When resizing the cases I always make sure the inside of the necks are lubed so that the expander plug pulls out with equal resistance and doesn't pull the neck out of square. With RCBS and Redding dies I also will leave the decapping rod slightly loose in the die so it is able to centre in the neck while it is withdrawn.

Before seating the bullet I start by making sure that the case mouth has a good chamfer on the inside. Once the bullet is started in the case about 1/2 way I will back off on the press handle and rotate the case 180* and finish seating the bullet. I also am anal about making sure the case is fully seated in the shell-holder as I have found that if the case is the least little amount of out-of-square with the ram bullet run out is sure to occur.

I do everything you do.
With boat-tail bullets I get better results than flat-base. More chance for it to tip a bit I guess.Tom

[Cariboo]

With boatatils I use a Hornady VLD chamfer tool and actually cut it in fairly deep. They perch on the case mouth really nice and are very easy to start straight.

I have looked at some of the "straightening" tools for loaded rounds over the years and have always wondered if they would really make a difference or if I was just looking for another excuse to "tinker"! LoL


In any case after I load a batch of cartridges I will run them through the concentricity gauge and put aside the best ones for hunting and use the lesser rounds for off-hand practice. With that said I am pretty sure I could run a round through any of my rifles with .010" run-out and still hit a mulie in the lungs at 300 yards!

[BarryL]

Try seating the bullet half way in then raise the ram, turn the cartrige 180 degrees then finish the seat. As for your run out at .005" I wouldnt worry about that at all. Its going to have to come out a fair bit before your going to notice anything in your groups at hunting distances. In my BR rifle theres no noticable difference between groups of .000" run out and .005" at 1000 yards.

[ruttinbuck]

Sounds pretty universal in seating technique as I follow what the other guys have said.Only thing I do differently is rotate the round and seat at four intervals instead of two.My rifles are plenty accurate with my home rolled ammo.RB