Just loaded up some brass that was once fired in a new 308. 20 pieces of Lapua, and 20 pieces of Winchester Nickel plated brass. All loading techniques were identical for both cases.

I checked runout on these rounds, and they were great until the bullets were loaded, a LOT of runout was introduced into the rounds at the bullet seating stage. I noticed this during loading the Lapua brass, and then just went ahead and loaded the rest of the cases as I only had one 308 Cal seating die available.

After all the rounds were loaded I checked the runout on the bullet for all rounds, and interestingly, they runout was about 75% less on the Winchester nickel plated cases...Hmmmmmm

All I can guess at right now is that maybe the Win Nkl cases were a bit 'stiffer' and therfore remained closer to the chamber with less springback than the Lapua cases????

It was also interesting that when straightening the rounds with the Bersin Tool, the Win Nkl Case based rounds, were much easier to tighten up on the concentricity than the Lapua based cartridges, and I was able to get the Win based rounds to a lower runout number than the Lapua based ones.

A question to Bersin users, what technique do you use to straigten? I tend to rotate the round til I am on the high side of runout and then try and use one strong 'push' with the screw in adjuster to get to straighter ammo, but I have toyed around with just 'bumping' the bullet several times quickly and see what I get....What's ya'lls style?

Hey Fish

Yeah, it doesn't take long to figure out that the Bersin tool is a runout reduction device not a runout eliminator.

There is a certain feel to it. I also try to do it in one push but the amount of push needed is different for each loading. Sometimes you only have to give a little push and carry the needle from it's 6 o'clock position up to 8 o'clock. Other times it will need a push from the 6 o'clock up to and past the 12 o'clock straight up. It seems to me that new cases or cases that are annealed are much easier to push and come out of the seater with more initial runout. Give me a 4 times fired or more hard neck brass that has a good crimp from a Lee Factory Crimp Die and within 2 or 3 cases I can have the feel of how far to push it down pat. And it will stay there once pushed. That is probably comparable to your nickle cases which would not have soft necks like new ones or annealed ones.

It seems that the odd loaded case that has more runout can be straightened, but the runout can not be reduced to an equal or lower level of runout than one where you started with a straighter load to begin with. I would roughly estimate that whatever runout you start with on a case you can reduce it by 70 to 80%. I had to learn when to stop chasing perfection around by pushing a small amount of runout from one side to the other. All you are doing then is loosening the grip of the neck on the bullet and it will get looser and looser.

With new cases or annealed cases it is not hard to take and create runout by pushing it with your fingers and when you're through straightening it with the Bersin, it feels like you have it balanced there and have to handle it carefully to keep it there. Makes you wonder how much runout you create with chambering.

Still best to load rounds with very little to no runout to begin with and use the Bersin to check and correct the odd one that has a more than acceptable amount.

Woods, that is a good recap, and mirrors my experience. I always stop moving around the bullet after a few tweaks with the bersin for fear of exactly what you said--loosening the bullets overall neck tension.

I wonder how nuts this is--could you get one of the mfgs. like, Forster say, and send them a dummy round, and have them make a finished ammo die?????? A die that would have your entire round squeezed into proper alignment, with that specific bullet???

I guess I'm focusing to much on reloading this weekend--brain was fried from work........

Don, I'm surprised that the Lapua cases had more runout than the Winchester. Usually for me it's the other way around.
The expander ball is usually the worst culprit for me when inducing runout, not the seater. But then again I've been using mostly Redding Micrometer seaters and they're pretty good.
Like you and Woods I've found that it's best to get the first push to do most of the straightening. You can get a little dimple in the bullet that starts messing up your readings if you are pushing to often. I usually try and get rounds to less than .002 which is usually possible if the rounds aren't too far off to start with.
Which indicator are you using? the mm or tenths?........................DJ

DJ, I think this tool has an indicator that is 4/10,000's or something?? Does that make sense. I know my Sinclair concentricity gauge is 1/10,000--maybe the Bersin is .04 10,000's

I have a hard time getting them any tighter than whatever the heck is the difference between one number and another say from 4 to 5 ???

I was also surprised of the Lapua vs the Win, but I think Woods is right the 'stiffer' and therfore holds concentricity better??

I have ordered a Redding seater BTW for this 308, I have a Forster coming for the other one.