Acceptable "Run out" ?

[shoot4fun]

I check runout on a Forster tool but only the first couple of rounds. I want to verify everything is set up correctly in the press and don't sweat over anything within +/-.003 total runout.
Turning necks: IMHO a person can induce a lot of runout if they are not doing it right. I feel turning necks is not to cure runout but to improve neck tension consistency. Could be wrong.
OP, there are many factors that could be opening up your group size including, ahem, sloppy gun handling. It happens to all of us over time and we develop bad habits without even realizing it. Have someone you know has the skills fine tuned to take a look at your form. I'm not ashamed to admit that it happens to me.

 

[Milo 2.0]

I was under the assumption if you used a concentricity gauge for runout and your number read .003", you divide by half and then it would be .0015".
Am I wrong here?

 

[RMiller]

I was under the assumption if you used a concentricity gauge for runout and your number read .003", you divide by half and then it would be .0015".
Am I wrong here?

Thats correct. .003 is your TIR. "total indicator reading" your only actually off center by half in this case is .0015

 

[Milo 2.0]

Thats correct. .003 is your TIR. "total indicator reading" your only actually off center by half in this case is .0015

Thanks, hope the op is aware of this.

 

[drumcorpschamp]

I shoot 600 and 1000 yard benchrest and I take the time to sort rounds by runout. Any rounds that show more than .002" t.i.r. are used for sighters.

To the OP....Have I proven to myself that this makes a difference on a record target, no. But I go to the line with confidence in my ammo and in my rig. To me, that makes it worth the time.

Good shooting,
Jerry

 

[Raythemanroe]

I don't check concentricity every time, just to make sure all is well.. Seating depth in my opinion shows up more on paper, neck concentricity (thickness) and the all important bullets..Spend your money on a good scale and tools to measure bullets..JMHO use Graphite or Molly on the necks..

Ray

 

[Danattherock]

Hey guys, I am looking for some guidance on what an acceptable amount of "run out" should be on my prepared cases, and then on the loaded finished product? I am fairly new to reloading and have been told that concentric loads will improve my group size/precision? I am using the 21st Century gauge and if I am reading the dial indicator properly, the first 10 or so I checked is looking about .0025" - .003" on average if that makes any sense. Hopefully I have the gauge set up correctly so I am not getting bad data?

I don't shoot bench rest or F class so take that into account. I shoot PRS and similar tactical steel matches, 1-2 MOA targets out to 1,000 yards basically. My runout is 1-3 thou typically, and when I check rounds on my 21st Century Concentricity gauge (excellent tool) I will toss anything 5 thou and over into my practice pile. For matches I'm shooting 1-4 thou runout.

This ammo shoots 5-6's at 100, 1.25" 3 shot group at 400, and 6" 5 shot group at 900 yards, all prone with bipod. No neck turning, no annealing, no brass sorting, charges thrown with two Chargemasters, in a bone stock Ruger Precision 6.5 Creedmoor. Runout is one of many rabbit holes in reloading you can go down. I use my concentricity gauge as a diagnostic tool to be sure me and my dies are doing their job.

D Moran gave the best advice in this thread.


Dan
NC

 

[Lucky7]

Thats correct. .003 is your TIR. "total indicator reading" your only actually off center by half in this case is .0015

Rmiller, so if I understand you correctly, if I run my prepared case or loaded round on the gauge and it only moves a maximum of say .003", then my actual run out is .0015". I am not sure if I am understanding correctly or not? Also, someone in another post talked about inducing additional " run out" when sizing and using the expander mandrel? I am using some custom Whiddon dies that were built from 3 fired cases that I sent to them. Do you think the dies are not good, or just maybe I have them set up correctly?

Thanks,

 

[Dusty Stevens]

Are you using the expander on the whidden decapping pin? Plowing an expander back thru induces runout on all but the most perfect brass. Also make sure your case has slack when going in the die- not bound up in the shellholder. Make sure the die is doing the work and the press only pushes it in there and pulls it out- not influencing it in any way

 

[RMiller]

Rmiller, so if I understand you correctly, if I run my prepared case or loaded round on the gauge and it only moves a maximum of say .003", then my actual run out is .0015". I am not sure if I am understanding correctly or not? Also, someone in another post talked about inducing additional " run out" when sizing and using the expander mandrel? I am using some custom Whiddon dies that were built from 3 fired cases that I sent to them. Do you think the dies are not good, or just maybe I have them set up correctly?

Thanks,

Yes that is correct. A reading of .003 on your indicator is actually only .0015 off center. Most people who describe what they have ie... I shoot anything less than .002 for my record rounds are in fact describing "TIR"
"Total Inidcator Reading" that is actually only .001 off center. Think of it like this, If you raise the neck of a perfectly true piece of brass .001 the top will read a movement of .001. The bottom would read a move -.001. Now spin it. Your indicator would see the top side that reads .001 and the bottom side would read -.001. That is .002 TIR but you only moved it .001.
If you raise that same brass .003 then the top side moved .003 and the bottom went to -.003. Spin that same brass and you would see .006 TIR. I hope that doesnt confuse anyone further.
To me it is important for people to understand this. If one doesnt understand what they are measuring then trying to fix it becomes
difficult.

Expander mandrels can and do induce run out if your expanding force is to great. .001 is a VERY small amount. Magnified by double when spun.

 

[ireload2]

In my younger years I spent 10,000 hours running an engine lathe. Many parts had to be ran in a collet or dialed in with a test indicator. I found that I could see down to .003 TIR - total indicated runout on the indicator.
If you roll your ammo across a smooth flat surface like a glass or granite table or counter top you can see the bullet tip wiggle .003.
If it is of any concern roll your ammo across a smooth flat surface. If you can see runout on any round cull it for a fouler.
I used to make instant match ammo like this from military ammo. The stuff with runout always shot worse groups than the ammo with no runout.

 

[Lucky7]

Are you using the expander on the whidden decapping pin? Plowing an expander back thru induces runout on all but the most perfect brass. Also make sure your case has slack when going in the die- not bound up in the shellholder. Make sure the die is doing the work and the press only pushes it in there and pulls it out- not influencing it in any way

Yes, I am using the expander on the decamping stem. I also run them through my expander that I use for neck turning just prior to priming the cases. Should I not use the expander inside the dies?

 

[Lucky7]

Yes that is correct. A reading of .003 on your indicator is actually only .0015 off center. Most people who describe what they have ie... I shoot anything less than .002 for my record rounds are in fact describing "TIR"
"Total Inidcator Reading" that is actually only .001 off center. Think of it like this, If you raise the neck of a perfectly true piece of brass .001 the top will read a movement of .001. The bottom would read a move -.001. Now spin it. Your indicator would see the top side that reads .001 and the bottom side would read -.001. That is .002 TIR but you only moved it .001.
If you raise that same brass .003 then the top side moved .003 and the bottom went to -.003. Spin that same brass and you would see .006 TIR. I hope that doesnt confuse anyone further.
To me it is important for people to understand this. If one doesnt understand what they are measuring then trying to fix it becomes
difficult.

Expander mandrels can and do induce run out if your expanding force is to great. .001 is a VERY small amount. Magnified by double when spun.

Thank you for the clarification. I did not completely understand that concept before, but feel much better now that I am informed. Now I guess is the hard part trying to get perfect brass!