Neck run-out

[live2huntmt]

Using my Forster Co-Ax press and Redding competition bushing dies w/ no expander, I am measuring on avg .0015" of neck runout. After expanding with a Sinclair mandrel, I am measuring about .002 telling me I have about half a thousandth of neck wall difference. (Matching my ball mic measurements)

Is there anything I can do to decrease my neck run-out? Is .0015" acceptable?

 

[milo-2]

I would seat a couple bullets and then measure runout on them. That is the true measurement, not that knowing what is going now is bad.
I had the exact same issue with Redding bushing dies, .0015" runout on necks, switched to Whidden sizers and reduced it to under .001". I really can't say my ammo improved because I did switch.

 

[kiwikid]

Have you measured the neck diameter of your fired cases? If it is more that .004-.005" larger than your sized cases Redding suggest sizing in more than one step.
For example I have a 6.5x55mm here that the fired RWS brass measures 0.299", loaded rounds measure 0.293" so with my desired .002" of neck tension my sizing bushing is 0.291".
Sizing from .299" straight to .291" was producing around .002"-.003" of neck run-out, by first using a 0.295" bushing and then the 0.291" bushing my run-out reduced to .001" or less.
This is also with a Foster Co-Ax press and Redding Competition Dies.

 

[live2huntmt]

Have you measured the neck diameter of your fired cases? If it is more that .004-.005" larger than your sized cases Redding suggest sizing in more than one step.
For example I have a 6.5x55mm here that the fired RWS brass measures 0.299", loaded rounds measure 0.293" so with my desired .002" of neck tension my sizing bushing is 0.291".
Sizing from .299" straight to .291" was producing around .002"-.003" of neck run-out, by first using a 0.295" bushing and then the 0.291" bushing my run-out reduced to .001" or less.
This is also with a Foster Co-Ax press and Redding Competition Dies.

I did not know this! I'm definitely going to give it a try! Thanks

 

[Deputy819]

.0015 TIR is actually pretty dang good. I'm certainly not a bench-rest shooter, but I doubt you'd see a quantifiable difference on target with less TIR than that. Considering how many variables there are in this hobby I'd probably concentrate my efforts somewhere else, but that's just me.

Here's a short article from Sinclair on TIR that you might find interesting...

All SINCLAIR INTERNATIONAL Products for Sale Online - 236 Products

Brownells has 236 SINCLAIR INTERNATIONAL products for Sale Up To 91% Off including Reloading, Tools & Cleaning, and Gear.

www.sinclairintl.com

 

[Savage 12BVSS]

You are doing good and keeping TIR very low. We all have our own ideas about how much runout is tolerable. Shooter and gun need to be able to see runout improvement on target. I like to see 1/2 thousandth's or less out of chamber after being fired, all my guns accomplish this. I like to see one thousandth's or less after full length sizing without expander ball or spindle and mandrel neck sizing. After bullet seating with a forster benchrest seater die and turning the round twice during full seating stroke I still want a thousandth's or less TIR on bullet. About 3/4 of my loaded ammo accomplish this and are done, the other 1/4 get a quick tweak on the hornady concentricity gauge to come in under one thousandth's. I think I hold the runout lower than most would and don't debate that point, like I said we all have our own amount thats tolerable. Distance shooting shows up runout effect the most of course, when you only have to adjust 1/2 thousandth's or less its quick and easy. On the hornady one very light tweak with no risk of pushing neck out of round.

 

[Terry Balding]

Chamber one of your loaded rounds, the remove it and recheck it. You may be surprised.

 

[J E Custom]

The first thing you need to do in my opinion is the find where the runout is coming from. I would recommend turning the necks first to get the wall thickness the same, (Preferably while new).

Then load and fire a few of them and check the fired cases for runout. This will verify that your chamber is concentric and has no runout. If there is no runout on the cases at this point, you are golden.

Once this has been done start the loading process and check for runout after each step. Sizing and bullet seating is normally the place you add runout if the press setup or quality is not there.

Find whats causing the runout and you can address it. You will still occasionally end up with a few that have runout, so sort them and use them for practice or close up hunting.

I consider .001 to .002 to be my limit for any decent accuracy but if you can bring it down to .0000, it will out perform all the rest of you loads with runout.

J E CUSTOM