??Fixing Concentricity

I dont have one of those Hornady Concentricity checkers, and I dont have the time to use one anyway, but I have rolled the bullet down the glass trick. I have heard of people using different methods to straighten bullets, but does it actualy help? I kind of thought that as soon as the bullet starts to release, the case would spring back anyway. Is there any benifit to straightening, or is it best to do as I do and save the wobbly ones for regional shoots, foulers and sighters?
 
Straightening is one of those confidence things - it comes down to belief & belief either comes from an epiphany or by hardnosed experimenting. Epiphanies tend to lack substance in our game & I'm too bloody lazy to experiment much for the hell of it these days, so I avoid issues like this.

I avoid it by cobbling my loads in a way that I know gets the results, & as I said before in part, to avoid excessive runout. I chamfer the inside of case necks with a Wilson 17 degree tool, neck size with the Lee & seat with a premium micrometer adjustable tool. I don't have to body size for the life of a barrel as I run a batch of 5-600 cases for either my F class or 1200 yard gun & they don't grow a damn when sized with the Lee. The significant elements are that I'm using fitted brass with necks that are concentric with the body & projectiles that are induced to seat straight by using dies that operate coaxially & have properly formed punch heads.

Then, I protect against possible cockups with my loading by having my chambers cut with .0005" over projectile diameter throats. This is just a belt & braces thing as far as this concept goes (though I use the minimum necks for other reasons as well) & I have achieved quite acceptable results loading according to the procedure above with rifles that had factory chambers. Hell, I shot half minute aggs (at times) as a kid 45 years ago using a pretty much standard Sako L461 heavy barrel .222 Magnum - the barrel was stock anyway.
 
Some rifles/ bullets may just tollerate crooked ammo much better. It
would be much better to load straight than to straighten. It is time
consuming to straighten and It may also upset neck tention. I have seen
a gun loaded with straight ammo, produce fliers regularly with a round
that has been offset to crooked by .004. Should your rifle shoot at jam,
your situation may be much different than if it requires jump. Simply
having a throat that is .0005 over bullet diameter is no assurance that
your gun will straighten. That the cartridge stamped on the die is correct
does not make it a great fit with your gun. That the seater is correct and
of good quality does not assure that no runout will exist. You must
check everything. This die or that one is not neccessarily bad, it just
may not be for your gun, but great for another gun.
 
When chasing concentricity

Technique is very important, setting up the sizing and seating dies is very important...

HOWEVER using great brass such as Lapua is the most important part, but without the concentricity gage you will never know.

Look for 0.0015 or less on the bullet just north of the case mouth.
 
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John S said:
Technique is very important, setting up the sizing and seating dies is very important...

HOWEVER using great brass such as Lapua is the most important part, but without the concentricity gage you will never know.

Look for 0.015 or less on the bullet just north of the case mouth.
Click to expand...

I'm sure you meant .0015
These numbers are very relative to how the round is supported
while being indicated. Indicators with long plungers are somewhat
iffy, and can read differently depending on how the round is indicated
 
Bob -- that was what I found with my "homemade" gauge -- it was very sensitive to how I pushed, prodded the round. Hopefully the sinclair with its ball bearings will be a little more repeatable!
 
VaniB,
Having spent some time chasing concentricity, when I saw a report of such excellent results, my focus went entirely to that. As to your targets, they are obviously excellent....in order to get those results, you have to get all the details right. Are you shooting in competition?
 
If I full length size I remove the sizing button and go back and expand the neck to a diameter that gives me the size I need. It seems like the button is just too much torque and I get tweaked.
I get the best results when I use the Lee neck sizing die and do any annealing after the sizing is finished.
I've managed groups fairly consistent at 3/8 but run out haunts me. I get the best results when I fire form, neck size, then finish by annealing. That sequence usually yields under .001 r/o. The velocity is consistent the sd stays low and groups seem predictable.
 
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