Cartridge concentricity/run out

[squirrelsplitter]

Can anyone offer an opinion on what is an acceptable amount of bullet run out?
I am very new to metalic reloading. Currently working on 204 Ruger loads for AR 15 varmint shooting. The tools that I have aquired are the following.
Redding T 7 press and dies
Redding competition seating die
Sinclair concentricity gauge
21st century concentricity gauge
I am measuring any where from .0015 - .007 of run out.
Any help and guidance would be greatly appreciated.

 

[INShooter]

I shoot 100...200 yard bench-rest with a ppc. Anything over .001 run out bothers me. If you are getting .007, I would suggest you check your dies. Also, what is your run out on a fired case? Compare that to a sized case and see if you can pinpoint were the run out is coming from. Having said all this however, I cannot give a definitive thought on how much this affects accuracy. Too often we chase small details when the shooting conditions really determine our results.

 

[dkhunt14]

I don't believe anything under .002 to .003 could be seen in your AR. You need to find out where your getting the runout. Are they straight after firing? Are they straight after sizing? Is it being caused from bullet seating? One thing is, if you are sizing using a bushing die and not turning the necks you will have runout. The bullet is not in centerline. Matt

 

[gotcha]

Can anyone offer an opinion on what is an acceptable amount of bullet run out?
I am very new to metalic reloading. Currently working on 204 Ruger loads for AR 15 varmint shooting. The tools that I have aquired are the following.
Redding T 7 press and dies
Redding competition seating die
Sinclair concentricity gauge
21st century concentricity gauge
I am measuring any where from .0015 - .007 of run out.
Any help and guidance would be greatly appreciated.

......1st check your RO at each stage of reloading to identify the source of excessive RO. I strive mightily to keep under .003" at mid ogive. (bolt rifle) The AR's tend to knock cartridges out of concentricity by virtue of their slam feed... Make up some dummy rounds using spent primer and normal powder charge for proper overall weight. Use your concentricity gauge and mark high spot on bullet then cycle the rounds through the action using the charging handle. re-check RO to establish how much RO is being created through simply feeding the cartridges and use that measurement as your "max" RO....... Eject the cartridges as slowly as possible so as not to create more RO on ejection.

 

[squirrelsplitter]

I don't believe anything under .002 to .003 could be seen in your AR. You need to find out where your getting the runout. Are they straight after firing? Are they straight after sizing? Is it being caused from bullet seating? One thing is, if you are sizing using a bushing die and not turning the necks you will have runout. The bullet is not in centerline. Matt

I shoot 100...200 yard bench-rest with a ppc. Anything over .001 run out bothers me. If you are getting .007, I would suggest you check your dies. Also, what is your run out on a fired case? Compare that to a sized case and see if you can pinpoint were the run out is coming from. Having said all this however, I cannot give a definitive thought on how much this affects accuracy. Too often we chase small details when the shooting conditions really determine our results.

Thanks for your input! This gives me the direction needed to figure out where the run out is coming from. I am not turning the necks now, but I did just get a 21st Century neck lathe. The thing that puzzles me is that after checking 200 rounds loaded on new Norma cases, about 25% of them had .004 or less
run out, some had less than .0015. I did run the new brass through the FL sizing die because several cases had out of round neck openings. I have seen this out of round condition with all of the new brass I have bought?? Hornady, Winchester, Nosler, and Norma. Is this the norm?

 

[dkhunt14]

Runout is usually really good on new brass. I don't run them through a die. I chamfer inside and out. I run an expander mandrel, like the one to turn brass with, to even out the out of round brass and get less tension. New brass usually has a lot of tension. Load and shoot. Matt