Hello!
In the past, I've always purchased factory match ammo and premium hunting ammo, shot it, then reloaded it afterward.
The other day, I purchased a few bags of Winchester bagged brass, with the thought of handloading it for accuracy right from the start and skipping the factory ammo expense. Welll.......
I debagged about a dozen rounds, put it on my spinner, and was shocked to find myself reading an average of 0.005" runout of the case necks! I rarely ever get more than 0.002" of neck runout with factory ammo brass after shooting it.
Is the large runout of unloaded brass typically this bad? Do I need to load it up with some cheap bullets and heavy loads and fireform it in my chamber to correct runout before it will be any good for loading accurate cartridges? Is there something else I need to be doing?
Thanks!

Not surprising. Your chamber reduces the runout when you fire it. Your die may then screw it up again though!
Peter.

BEFORE you put em on the spinner you did run the case necks over a mandrel or sizing ball to straighten out the case mouths a bit?? If not...and cosidering the many tiny dents in bagged ammo....I'd say you got a normal result.
Run the case necks over something to get them round and load em up....they'll be fine....a few may be a bit wobbly but I'll bet you'll find them pretty decent.

I use an expander to open my sized cartridge necks to 'fired' size then resize them. But, I do it in stages. That means pressing the expander or sizer in just a little, withdrawing it, turning the case and then a little further. This I do when I damage a case. For normal neck sizing, I follow the same procedure, likewise for bullet seating. I have not been able to measure any runout, and that's setting the cartridge up in a lathe using a dial gauge accurate to 0.01mm (0.0004") and measuring it from case base to bullet ogive.

as an absolute minimum I run virgin brass through a neck sizer before doing anything else to it.

As an example I like Norma Brass for my 6.5x55, but I have yet to find a piece of virgin Norma brass that will chamber in my Swede before it's sized and trimmed

Brass fresh out of the bag? The way it's bounced and bashed around in transit makes any precise measuring less than pointless if done before sizing.


AD

Hello again!
OK... I resized 5 randomly chosen cartridges from the bag, and re-measured on the spinner. The runout is still in the neighborhood of 0.004-0.005".
Just to be absolutely clear, I'm talking about the "offset" of the neck circle as compared to the main case body... NOT the "oval-ness" of the neck itself.
Any thoughts?

Shoot them and neck size they will fire form to YOUR chamber.

US1 -
That's the conclusion I've come to, try fire forming them and see if that straigtens out the necks.
THanks!

quote:

Just to be absolutely clear, I'm talking about the "offset" of the neck circle as compared to the main case body... NOT the "oval-ness" of the neck itself.

Gaillo, how do you know this? At this point I don't think you can tell the difference. If you resized the cases, you can turn the necks just enough to clean up the high points and then check the run out again. THIS will tell you what you are dealing with. Having said that, I am not sure that you will see the difference at the target, but it is always worth the try.
Peter.

Peter -

quote:

Originally posted by Peter:

quote:

Just to be absolutely clear, I'm talking about the "offset" of the neck circle as compared to the main case body... NOT the "oval-ness" of the neck itself.

Gaillo, how do you know this? At this point I don't think you can tell the difference. If you resized the cases, you can turn the necks just enough to clean up the high points and then check the run out again. THIS will tell you what you are dealing with. Having said that, I am not sure that you will see the difference at the target, but it is always worth the try.
Peter.

I know that the runout is "offset" of the neck (referenced to the main case body) because of my measuring jig design. I have constructed my own case concentricity gauge as follows:

First off, I have a set of 4 ball bearings sunk into an aluminum plate. They are arranged as two pairs, one of which is toward the primer end of the case, and the other just before the neck section. I indicate on the neck itself.
There are also two more spots (holes) for ball bearings directly aligned with the center of the neck. After taking the "offset" measurement, I move the two bearings from the "just before the neck" section to the "on the neck" section, and see if the neck is truly circular or if it has an "oval" cross section. By comparing the two sets of readings, I can tell WHERE the actual defect in case geometry is located - whether it is an out-of-round neck or the neck being offset from the body "cylinder" (what I'm calling "offset").

By taking these measurements, I've determined without any doubt that the problem is neck "offset", not neck "oval-ness".

Hope this answers your question!

Nosler and Lapua brass seem Ok prior to fireforming

how does a random batch compare after full legnth resizing???

quote:

Originally posted by Gaillo:
The other day, I purchased a few bags of Winchester bagged brass...

Welll.......I debagged about a dozen rounds...

That could be your problem right there. I think I read somewhere that Winchester brass doesn't take to being "debagged" like some other brands.

I'm some what puzzled as to why You were shocked to find run out on those cases ?. Are they Match Brass ?, If not I fail to see the concern !.

If ones purchasing " Match Grade " components then Yes I would be upset .

To be truthful be thankful that's all the further out that Winchester brass is !.

Shoot Straight Know Your Target . ...

Thanks Gaillo. My gauge just has the bearings supporting the case and a dial indicator for the neck (or bullet). It may have the bearings for the neck, I don't know, I have not used it in years! I just let my targets do the talking.
The question really is " If I can't get zero runout, how much is acceptable"? And there is no answer except at the target, IMHO. Now, if you are going to obsess about it then you should get a straight line bullet seater die and arbor press as well.
Peter.

Dr.K - I guess the only reason I was a bit shocked, as I said in my first post, is that I'm used to buying factory ammo, shooting it, then measuring 0.001-0.002" runout. Reading 0.005" from brand-new brass just seemed like a bit of a letdown by comparison.

Peter - I'm not sure how much runout is "acceptable", as my only baseline so far is reloaded factory ammo with 0.001-0.002" runout. I'm going to try loading some of the Winchester stuff and see how it compares, like yourself, I think the end-result is really what counts!

Thanks everyone!

I would not be suprised if the factory ammo you bought in the past had a runout of .005" before you fired it. Like everyone says once you fire the brass the runout will come down. What you are seeing is nothing new with cheap remington or winchester brass....

I neglected to add what McKay posted which pretty well sums it up .

Shoot a couple remeasure and post what the results are .

Shoot Straight Know Your Target . ...