Bullet runout, how much is too much?

Kelly Timoffee

Kelly Timoffee

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So , slowly stepping up my technique so tonight I decided to check some rounds I loaded.

I had some loaded ones left that were done with a collet sizer.It has failed recently so I went to my bushing sizer.

Recently purchased a dial indicator so I can check these things.

My rounds I previous did had bullet run out of 0.001" - 0.002" very evenly and consistent.Collet sized

The bushing sized rounds were exactly 0.006" - 0.007".

Where does one draw the line and correct or change , I know the target will speak for itself but what is the consensus on how much is too much?
 
Tagged for interest. I personally only use Lee collet neck size dies and have no experience with bushing dies at all. The few rounds I've checked over the years have always shown little to no run out, 0.001-0.002" as you say. I use them because they are cheap and produce good results, I'm not proficient enough to benefit from anything better lol.
 
Check out this review on some dies and bullet runout. Too bad they didn't include Forster and Lee.

http://riflemansjournal.########.ca/2009/09/reloading-seating-die-runout.html
 
my PERSONAL opinion, any thing i load that's .003 or over goes into the long range steel bashing pile, if i want to try my hand at ragged groups on paper. i use all .002 or under.

currently im using redding competition bushing neck sizer, competition bullet seater and forester co-ax press, my "long range steel only" pile is pretty sparse, meaning 99% of what i load is .002 or under, the odd one thats over, is usually due to my brass prep where i didn't quite take the bur off the inside of the neck after trimming.

realistically, i highly doubt that if the odd .003/4/5 ended up in my ammo box while trying for groups, thatd id ever notice, i can honestly say, that im a consistent and constant 1/2 MOA shooter, but the odd .1 / .2 MOA groups i get are 1/2 skill but mostly luck, so until i get to top tier benchrest level (aka never) im not gonna get overly bothered by the small differences
 
Over the years, I've noticed the tough shots at long range don't produce as many hits if runout gets much over 3 thou at the ogive.
This, with a half MOA (at 2-400 yds) rig and shooter, out at 800-1000 yds.
The collet/'M' die/BR seater combo, works well for me. 0 to 2.5 thou. runouts are typical, most of 'em stay well inside 1.5.
 
I tried 2 different tools for measuring bullet runout and was somewhat disappointed in what I found.
RCBS shows me .005 on a particular round.
Hornady shows me .002 or less on same round.

I've returned the Hornady tool. I also found that when trying to correct the runout with the Hornady tool, it seemed to only put small dents in the Berger hybrids while not actually correcting the runout.
 
I use a Sinclair Concentricity gauge.

Using Lapua brass, Redding Comp bushing neck sizer and seater, I usualy get less than a thousand bullet run out. The needle barely move on the indicater.

Mush
 
Depends on the bullet. Some are very sensitive, others don't give a rip. BUT it never hurts to keep this dimension as low as possible.

As you said, let the target tell the tale.

Now here's a fun test. Take some ammo and mark the runout it has now. Stick it in your ammo box and take to and from the range the same way to carry all your ammo. Measure it after.

Jerry
 
Shooter ----/ said:
I tried 2 different tools for measuring bullet runout and was somewhat disappointed in what I found.
RCBS shows me .005 on a particular round.
Hornady shows me .002 or less on same round.

I've returned the Hornady tool. I also found that when trying to correct the runout with the Hornady tool, it seemed to only put small dents in the Berger hybrids while not actually correcting the runout.
Click to expand...


I have expierienced the same thing. I believe the readings you received ie, .005 & 0.002 thou are the same result. Somebody correct me if I'm wrong, but the way you measure on the RCBS or Sinclair tool is not based off the "bore axis of the cartridge" so you actually have to divide by 2 to get the "runout" which would make sense between your two gauges ie 0.0025" and 0.0020.

Evan
 
Mystic Precision said:
Depends on the bullet. Some are very sensitive, others don't give a rip. BUT it never hurts to keep this dimension as low as possible.

As you said, let the target tell the tale.

Now here's a fun test. Take some ammo and mark the runout it has now. Stick it in your ammo box and take to and from the range the same way to carry all your ammo. Measure it after.

Jerry
Click to expand...

I'll that challenge quite anxious to see the results.

Mush
 
Another question. All that discution makes me wonder about my technique of measure run out with Sinclair gauge.

The 2 bearing surfaces are the case base and the bullet. While measuring at the ogive ? Right ?

Or do I put the "front" bearing surface on the neck ? And measure at ogive ?

Mush
 
Oups !

I watched a Sinclair you tube vid about the gauge.

I might have more run out out that I tought :)

If the 2 bearing surface are on the case itself (not on the neck) , I ended with 3 thousands run out at the ogive.

Hum....makes me wondering.

Mush
 
More ammunition is reloaded with excess neck runout because the decapping rod/Expander button is locked down off center than any other reason. Full length resize a case with the decapping rod removed and measure the run out at the neck, now reinstall the decapping rod and resize the same case again and check the runout. (what did you find?)

Now look at the Forster full length resizing die at the link below, notice the rubber washer under the decapping rod lock nut that allows the rod to "float" and self center in the case neck. Also notice the neck of the case is still inside the neck of the die when the expander ball enters the "centered" neck neck of the case. By using a rubber o-ring under the lock nut of a standard die and raising the expander button you can accomplish the same thing, wink, wink hint, hint.

http://www.forsterproducts.com/store.asp?pid=36197

Case necks with uneven wall thickness will also cause the neck to be pulled off center due to the thin side of the neck expanding more.

NOTE, the U.S. military considers neck runout at .003 or less to be match grade ammunition, and this applies to any stock factory rifle with a standard size chamber. On customs rifles with tight chambers used in competition then most shooters try for .001 or less runout. and shooting bug hole groups.

I use a RCBS runout gauge and the Hornady gauge, the Hornady gauge allows you to "bend" crooked ammo resized from cases that have unequal wall and neck thicknesses. Meaning you can tweak warped cases and shoot better groups, and the Hornady gauge measures along the center axis of the case so the readings are not off scale.

runout003_zpsd19b7cc3.jpg


Below is "WHY" the Hornady gauge has an advantage in tweaking poorly made brass.


neckcenter_zps94286f86.jpg


Also note that cases with dings on the rims and extractor groove can cause the case to tilt on the down stroke of the press and pull the necks off center. So "LOOK" for the causes of neck runout and try and cure them and if you can't then bend and tweak the case necks.
 
Just finished checking some reloads put together today and now reading this thread.
I have about .001 to .002 run out for the most part and anything over I try to straighten.
I don't deflect the bullet but I do deflect the shoulder area.
For those that do straighten ammo how do you do it?
I have drilled and reamed an aluminium block for the cartridges I reload for, that support the neck and bullet at the same time so I can tweak the alignment.
I have just started using Hornady seating dies for my 243 and 257 and so far I am finding out that they are no better than the my lee dies but better than Lyman and RCBS dies.

David
 
I spent so many years trying to "bend" rounds loaded in "standard" dies to low runout straightness. A tedious and frustrating exercise that only ever produced variable results on target.
Gave up on that whole thing.
These days, for the last decade or so, my loads are so consistently straight, that I never even bother checking for runout anymore.
Zero to .0015" or less is normal, .0025'' or more is very rare, usually caused by a case neck that needs attention, and are only used as foulers/sighters/plinkers, with a black marker applied to segregrate them for further work or reject.

The proccess:
Lapua brass, straight out of the box. Annealed every third firing.
Lee collet neck die, stem tuned to resize 3 thou. under bullet dia., cases run through the press twice, with a 1/4 turn beween ram strokes, cammed over press tdc method.
"M" die, dimensioned to open neck to 2 thou. under bullet dia.. IE: .2625" M die stem dia., for a .262" finished ID 6.5mm neck.
Redding or Forster BR seating die, with some attention paid to 'feel' on the ram handle while seating. The ones that 'feel' notchy or different, are different, and suspect.

A carefull post trimming deburr, with shallow angle reamer turned lightly inside, and a polish with 0000 steel wool wrapped round a powered bristle brush to break burrs.

Thats it.
 
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