Your personal boundaries for case neck runout?

[Rich Coyle]

Rich, are you able to maintain that .000-.001" runout throughout the loading process to your finished rounds? Very precise work.

I wish!

 

[jebel]

I take well the point that many of you have made that bullet runout is the relevant bit, not neck runout. But I think of bullet runout in two possible way. First, a bullet can be straight in the neck such that both neck and bullet runout are identical, if any exists. Second, a bullet can be skewed relative to the neck such that it has runout independent of the neck. The second seems worse to me, from the standpoint of a bullet being able to align itself in the throat, assuming you have full-length sized and room exists in the chamber for this alignment to happen. Would you agree, or not?

 

[bigedp51]

If you check your case for neck runout after sizing and have more after seating the bullet, then that is telling you something.

If you have a simple neck thickness gauge like the Redding gauge pictured below it will tell you a great deal. All you need to do is subtract the neck thickness variations from your neck runout reading to get the actual neck runout.

And if the runout increases after bullet seating you need to find out why.

Below the Forster benchrest seating die holds the case and bullet in alignment and the bullet can not tilt during seating.

 

[Rich Coyle]

bigedp51,
Man, I need that die. Do they make custom dies for wildcats?

 

[bigedp51]

bigedp51,
Man, I need that die. Do they make custom dies for wildcats?

I'm not sure if custom seating dies are made, but both Forster and Redding make two types of this same type die. The higher priced dies are micrometer seating dies but cost much more, the Redding die is $100.00.

The good point about this type die is it is able to slightly reduce/correct bullet runout. German Salazar did a test of various seating dies and these type came in first place.
The link below is the entire seating die test, but it is in adobe acrobat .pdf format so you need adobe reader to see it.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=0ahUKEwjsyonB-OLRAhXHOSYKHZSSCcoQFggaMAA&url=https://reloading.cc/forum/attachment.php?attachmentid=8532&d=1425564920&usg=AFQjCNEWbAvlft5hI_jioGKFvXlZelLjzw&bvm=bv.145063293,d.eWE&cad=rja

"The Rankings

And now, the moment you've been waiting for... #1 - Redding Competition Seating Die (sliding sleeve type, threaded die)

The Redding, which I expected to finish high, did what I thought couldn't be done - it produced rounds with an average runout that was less than the average case neck runout of the brass used. In none of the ten rounds loaded did the Redding increase the runout; it either held exactly the same or it decreased. The Redding, with an Average Runout Change of -0.0003" is the winner. The negative sign, of course, indicates a reduction in runout."

Below are targets from testing the seating dies, and the Redding die came in first.

 

[Rick Richard]

I think it's difficult to correlate with absolute certainty the effect of run-out on precision, accuracy, or ES, particularly considering differences in rifle chamber, bullet design, seating depth, etc. To your question, while range is certainly a function, I think more about the the angular dispersion(MOA) which more often then not correlates at longer ranges with a well designed load(stabile bullet and low ES). My standard of run-out was established quite a few years ago when I was heavily involved in 200/300 yard Egg Shoot Competition. This is essentially a bench-rest game, requiring the rifle to consistently shoot relatively long, time limited strings(10-20+ shots) into <.5MOA, the minuimum requirement to hit an egg at 300 yards(Much harder the it sounds!). During this rather intense period of shooting through thousands of rounds at actual eggs, sighter groups,and practice it appeared that the uniformity and reduction of fliers was related to the degree of run out with my loads. Initially, the bulk of my shooting was with a 308 hand loaded with 168 or 175 Sierra SMK's. I stumbled upon this when comparing my loads which were near identical in velocity, and POI to the Factory Gold Medal Match. While my actual groups size, on average, were smaller then the factory loads by about .25MOA, the factory ammo was typically more symmetrical in shape with fewer fliers. In an attempt to figure out the difference to my loads, I measured several different lots of the factory Match ammo, the average runout rarely exceeded .003", with most in the .001-.002"range. Mine were running .003-.005". When I "finally" reduced my run-out to <.003" and I found my groups more symmetrical with fewer fliers, and improved ES.....Most importantly, I improved my Egg Shoot scores! Thus, my .002" stantard, which I have since then, simply applied to all my precision loads. Coming back to the question asking, "What range is accuracy effected?" For those Egg Shoots it was 300 yards. In the case of my LR hunting, it's hitting the particular animals vitals out to 1000+ yards. I think a low degree of run-out(<.003") can only improve the chances of performance consistency, and the confidence that your average group(or shot) will be within your target, at whatever the calcuated range(WEZ)....IMO.[/QUOTE

Thanks so much for the reply. Is there anything in particular you do to achieve the low runout?

 

[Greyfox]

Quote:Rick Richard:
Thanks so much for the reply. Is there anything in particular you do to achieve the low runout?

Yes. It's important to make sure that even when using bullet guided seating dyes as described earlier in this thread that the seating alignment is near perfect, and seating pressure is light and smooth.
—Seating plug fit to the bullet is important. I have two different stems for my seater, both conventional and VLD. If the matched seater plug does not produce a low enough runout, try the conventional plug. I have a few loads where I get better runout with the "wrong" sized plug. Sometimes rotating the bullet 2-3x during the seating stroke can improve runout. Alternatively, placing a small rubber o-ring under the seating stem luck nut can enable self-alignment if the seater plug in the neck.
-I like a light, .00015-002" of neck tension, make sure there is slight chamfer in the inside of the neck. I prefer to clean with corncob leaving the carbon film on the inside of the neck for lubricity. Dry graphite for totally clean necks.
-I have been able to achieve .002" or less runout with,and without an expander depending on the particular load. The o-ring described earlier may be required if the stem is not perfectly straight. I will generally start without the expander. If runouts are high, I'll try the expander. It has improved runouts with several of my loads.
-I like to have a minimum of bullet bearing surface with the neck of at least 60%, preferably 80-100%.
-I have almost always been able to achieve low runout with these techniques but, if all else fails and runout remains high, change the bullet. This has also worked!