when checking concentricity how much run out is to much. just for fun I checked my big game loads and was surprised that I get up to .004 thousands out but the thing groups into an inch or less off the bench every time I go to the range..that's three shot at 100 yards.
I plan on doing a test when I have time and shoot groups with segregated loads to see what difference it makes
thanks

.002" is acceptable. Beyond that tests have shown that each .001" of runout exands groups �MOA. For short range, as a 100 yards shot, .004" would expand your group only �" but at longer ranges it could matter a great deal.

If you are a benchrester or shoot beyond 600 yards it can have an impact. At 300 yards and under don't sweat it unless you can hold a gun to .25 MOA repeatable accuracy. David Tubb can't...

Run out can be a very frustrating subject. RCBS says in the literature supplied with their Casemaster that .000 is acceptable for bench competition. .003" or less for Varmint Hunting and .004-.005 for Big Game. With a long list of qualifications I'd say that's a good guide, though not the end all on the subject.

I'm not going to try to detail the myriad of thoughts I have on the subject but will say it has a substantial influence on accuracy. I fiddle with die set up until I'm in the range of tolerance I desire, then use those beyond that for foulers. Also, I segregate loaded rounds in .000-.001" groups for the sake of practicality. I don't know that any circumstance can render all loads to a given tolerance except possibly arbor dies properly used. Oddly, the Casemaster ended my use of RCBS dies for the most part(brilliant marketing strategy) though I have a few sets that work well. It also reordered completely how I set up dies, and how they are used. Luck to you, have patience, be thoughtful.

The NRA and A.A. Abbatiello wrote an article that says mathematically .004" of runout [less than the eye can see] will cause 1.1 minutes of error in the direction the bullet takes when exiting the muzzle.

http://home.snafu.de/l.moeller/Geschosse/Bullet_Imbalance.html