Curing bullet runout in your cartridges.

[BoydAllen]

Usually it is the case neck that is angled slightly relative to the CL of the case body, and the seated bullet extends that angle (at best) resulting in increased readings the farther out on the bullet that they are taken (using a concentricity gauge that supports the round on the case body) Seaters cannot fix what sizing dies do but they can make it worse. Some time back I did a comparison of a Hornady seater and a Wilson using 6PPC cases with similar end of neck runout, and the Hornady gave twice the runout of the Wilson measured similarly.

 

[T-shooter]

Evidently, you have never used a WTC sizing die.

No. It's a Forster B/R die that has been hone and the ball resized. I doubt if any die would straighten the brass before it was annealed. It's too springy and would just try resume it's shape after any resizing attempt. This was the worst new brass I ever bought and I've had 350 new Hornady cases and about 300 new Lapua plus a box each of Federal and Winchester. If the WTC sizing die would cure that poor quality of brass, I would get one.

 

[chop house]

This was the worst new brass

sounds to be a nightmare, but also sounds like you've never run across starline cfr brass. i got some of early production release that was so hard it would NOT seal at all, especially with some shallow seated bullets. also problems sizing and seating iirc. so much for a bargain, eh?

i go the collet/body die/wilson route to good effect, but have modified spare mandrels to tune neck tension some when necessary. i've not tried to go too much undersize... follow manuf advice.

here's a separate question... do the steeper shoulders on the AI chambers help, hurt, or have no noticeable effect on runout when going the FL/expander button route?

 

[T-shooter]

Just looked up the WTC (Warner Tool Company) die. I'm impressed with the quality and depressed by the price. Not shooting professionally, I can't justify the cost plus a new press to mount it in. Would be nice to have!

 

[Tim Singleton]

Whidden makes an excellent custom dies at a great price

 

[T-shooter]

sounds to be a nightmare, but also sounds like you've never run across starline cfr brass. i got some of early production release that was so hard it would NOT seal at all, especially with some shallow seated bullets. also problems sizing and seating iirc. so much for a bargain, eh?

i go the collet/body die/wilson route to good effect, but have modified spare mandrels to tune neck tension some when necessary. i've not tried to go too much undersize... follow manuf advice.

here's a separate question... do the steeper shoulders on the AI chambers help, hurt, or have no noticeable effect on runout when going the FL/expander button route?

Never tried Starline brass. As far as the Hornady, my latest are a full 7% larger in capacity. At least I have a couple hundred of them but I have to rework the loads. It took nearly 8/10 of a grain of Varget to get the velocity back. Annealing the brass really helps making it pliable enough for the sizing die to to correct. Most after annealing and firing once will show runout of .001" or less on the turned necks. I can't answer your question. But with my die, there is no difference in runout using the expander ball since I run it high and the ball & shaft will self center.

 

[onelastshot]

The bullet isn't straight in the case neck. If you have much runout, you can see the bullet tip wobble when you roll the case on a flat surface. This means the bullet can enter the throat/lands with the tip not axially aligned with the bore.

Thank you!

 

[jamesdmock]

I use a Wilson die. How do you "float" the bushing? It just sits in there flush.

Just unscrew the top a small amount. If you wish, you can add a spacer under the cap, Some bushing dies do not require this and one can determine this by shaking the die and listening for the rattle of the bushing. If it rattles, then the bushing is not "trapped" into place. Good shooting....James

 

[Alex Wheeler]

If you want really straight cases move to a full length non bushing die with the neck diameter ground in the die. That will produce the straightest cases I have seen. The best shooting I have ever seen is still done with bushing dies and bullet runout. My 1k yd testing proved to me a little runout doesnt show up on target. ymmv

 

[BBNW]

If you want really straight cases move to a full length non bushing die with the neck diameter ground in the die. That will produce the straightest cases I have seen. The best shooting I have ever seen is still done with bushing dies and bullet runout. My 1k yd testing proved to me a little runout doesnt show up on target. ymmv

What would you consider a little runout, 1 thou, 2 thou?

 

[Alex Wheeler]

.001-.003 is normally what a bushing die seems to produce.

 

[mikecr]

I doubt it's the fault of a bushing itself leading to ~3thou of runout(which is high).
I say this because I always use bushing neck dies(Wilson) and my loaded runout off seated/exposed bullet bearing is normally below 1thou. If bushings were a problem I would likely have run into it by now.
Part of this is that I do not size case bodies other than shoulder bumping. Also, my first check of brass is for thickness variance(which I cull out), and I neck turn, and mandrel pre-expand.

If your running a sloppy chamber fit then runout won't matter. Things are different when running a tighter fit, but then your producing/maintaining way straighter ammo.
Probably what led to the current trend of oversizing everything for better results. This, producing higher runout, while also removing runout as a factor.

 

[Shynloco]

I believe that Alex and Mikecr are both accurate. I strive for runout to be within .001-.002. But what's weird is I have also found certain methods of "sizing" have built in competing interests. And sometimes, our dies themselves aren't as precise as we think they are. That's why "custom dies" are (IMHO) the way to go if you are trying to get the best accuracy out of your handloads.

And what Mikecr says about "sloppy chambers," I'm willing to bet that probably ALL "across the counter rifles" have that characteristic. And no matter the runout, that beautiful .001 runout won't achieve the best possible groups when fired out of a sloppy chamber. But I have also found that what Alex said about a FL die WITHOUT a bushing, might be the best thing in terms of concentricity. As an example, I have a cheapie Lee .308 FL die that produces runout of less than .001 - .015, using Lapua brass that has been carefully neck turned slightly to take off any high spots. Yet when I try and resize that same brass in my Redding FL or FL Bushing die, I get runout more in the .002 - .003. And when I then run that brass back through the cheapie Lee Die, I'm back in the .001 area. Go figure.

Alex

 

[Tim Singleton]

If you check runout on a sized neck and compare to the seated round you will find in a lot of cases more is induced by the seater
Even a Wilson inline with the set screw pushing the stem tight can't be straight
A Redding custom, Hornady or Whidden and I'm sure others with an internal sleeve that matches your loaded round with the bullet you plan to use is what it takes to get below .001

 

[butchlambert]

Speaking of PPC brass, I have my best luck fireforming first without a bullet. I do have a fireforming barrel as all of you should. One of the things that it does is to allow you to do your neck expanding of only a very few thousandths. I think expanders going from 223 to 243 causes neck problems. I make my own seater with my chamber reamer.

 

[Alex Wheeler]

If you are using a bushing die where the bushing floats your going to get runout. What is to ensure that the bushing will center on the neck and size it equally?

 

[jamesdmock]

If you are using a bushing die where the bushing floats your going to get runout. What is to ensure that the bushing will center on the neck and size it equally?

If one has a straight chamber, the fired brass will be straight. When the neck of that straight brass enters the tapered bottom portion of the floating bushing, it will be centered. Also, the brass forces the bushing up a few thousandths to the cap which is flat on the bottom resulting in low runout. I check my loads for runout and this method WORKS. If you doubt this, then give it a try. Good shooting....James

 

[Sheldon N]

I switched from a Whidden FL bushing die to a Forster FL die with a custom honed neck and saw a significant reduction in runout. Went from 0.003 (and sometimes higher) down to consistently <0.001.

 

[rcparker1]

I have started shooting group br with a well know shooter. He takes a Redding seater, pulls out the seating stem and sleeve and reworks them. He builds a new stem based off the bullet he's shooting. He claims after years of searching for concentric loads a EDM die and custom built seater is the best he's been able to load.

 

[seymour fish]

If you want really straight cases move to a full length non bushing die with the neck diameter ground in the die. That will produce the straightest cases I have seen. The best shooting I have ever seen is still done with bushing dies and bullet runout. My 1k yd testing proved to me a little runout doesnt show up on target. ymmv

Alex, agree 100 %. I see no degradation of accuracy at 1K with runout of .003. .005 and worse begins to show. These outliers often have abberancies in neck wall thickness and are relegated to " fouler" status

If you want really straight cases move to a full length non bushing die with the neck diameter ground in the die. That will produce the straightest cases I have seen. The best shooting I have ever seen is still done with bushing dies and bullet runout. My 1k yd testing proved to me a little runout doesnt show up on target. ymmv