Runout with a lee turret press.

[John Sukey]

Seems odd to me. All projectiles rotate around the nose, this is called nutation. they eventualy settle down before reaching the target.

 

[Mystic Precision]

Runout effect is relative to bearing surface. Short bearing surface bullets are more succeptible that long ones,and bearing surface is a ration of surfaace to over-all length.

Richard is right, 3 thou is an acceptable (and arbitrary) number. I call BS to the .4 thou resulting in 1 - 1.5 MOA.

I doubt I would have said that either as I have shot ammo with that much and was sub MOA.

Factory ammo has at least that much and some can shoot sub MOA.

But for teeny tiny groups, the lower the variations in all steps in reloading, the better.

YMMV.

Jerry

 

[Glock4ever]

I think another concern with runout is the shape of the projectile after it leaves the barrel. If it is slightly off center the engraving of the rifling on the jacket will also reflect that and could potentially cause issues in flight. Like Jerry said less variation is better - I do know that having great handloads will affect my confidence when shooting.

 

[AP]

A uniform thickness neck helps the expander ball to extract without pulling too hard on one side or the other. Also allows the bullet to seat square to the case more readily. Expander balls can be the source of some evil - have seen one that liked to shear off soft brass from the inside of the case ... which also pulled the shoulder ahead - and probably off center (can also change/lengthen the cartridge head space quickly) . Check them (expanders) for ridges and might be worthwhile to check that they are actually round. Forster dies seem to result in smaller run out. The Lee Collet dies seem to be pretty good. There are a number of contributing factors to run-out. Know of guys that just accept it and spin the loaded cartridge to find/mark the high (or low) side and orient them the same way in the chamber every shot.......

 

[JBD]

Ok I measured my runout and it is not great. We measured several cartridges lowest was 3 thousandths lots of 5 and 7 and one 15 thousands.

Ok my precision setup consists of a lee turret press and lee delux dies. What should I switch to improve my consistancy.

 

[kombayotch]

Don't automatically assume its the press. Try your dies on a friend's press and his dies on your press.

How many firings do you have on the brass? It may need to be annealed. Are you cleaning the case necks properly? Carbon buildup in the case neck can kill runouts.

What do the case neck runouts look like prior to seating?

 

[Mystic Precision]

Measure run out of the case out of the rifle. then measure that case through each step of reloading. You will quickly find where the run out is coming from.

Repeat and if runout occurs in the same spot, that is your problem

Jerry