Bullet run-out, what is it , and is there a gauge to measure this, and what are the effects of bullet run-out. Have a great day!!!

Runout is a measure of the extent to which the bullet in a cartridge is not concentric to the cartridge itself. Bullet wobble, in other words. Generally, a higher level of runout (say over ~0.004") will lead to decreased accuracy.

RCBS, NECO, Sinclair, and others make tools to measure runout. I bought the Sinclair tool and like it.

Hope this helps!

[ 11-02-2003, 10:51: Message edited by: achadwick ]

If you lay a loaded round on a flat surface and roll it the point of the bullet, if concentric, should not vary. What you are doing is projecting a straight line right through the round starting at the point. The concentricity guages measure this by placing a tip on the round and spinning the round. I understand this a lot better than I can explain it. Your accuracy will be related to the degree of out of roundness. Maybe someone can help me out with this. Best wishes.

Cal - Montreal