Bullet Runout

What do you believe is the biggest cause for bullet runout, press or dies? I know from experience, I have seen one show very little movement from the Sinclair gauge to have the following to come up with .005 runout, I don't get what is causing it, the sizing die on the neck, seating die or press?? I know it becomes frustrating when developing loads trying to see if it is the reload or the barrel not liking the combo.

Watching…
I've had the same experience.
Used Redding competition die without expander ball and mandrel…AND Redding FL bushing die with and without expander ball and mandrel.
Seated with Redding competition seater and Lee seater with same results.
It seems to have good runout then a .005 like yours.

Using a mandrel helps and I attempt to use same steady stroke of seating on all rounds.

I'll say it......bullet runout is like no. 5 on my list to affect accuracy. I stopped looking at it years ago after I developed my method and process to the way I reload. I can check any of my handholds now and I have none over 0.001". Most are not even measurable. With that said, try this. If you load say 20 rounds. Separate the them into lots based off runout. So say you got 4 that are 0.001" then shoot those together. Then if you have 5 that are say 0.005" then shoot them together. Then you can determine how much your runout is really affecting your load.

Roughrice said:

Watching…
I've had the same experience.
Used Redding competition die without expander ball and mandrel…AND Redding FL bushing die with and without expander ball and mandrel.
Seated with Redding competition seater and Lee seater with same results.
It seems to have good runout then a .005 like yours.

Click to expand...

It becomes very frustrating.

Run by my shop sometime and I'll explain it better. I just hate typing long responses on my phone.

Longtine88 said:

I'll say it......bullet runout is like no. 5 on my list to affect accuracy. I stopped looking at it years ago after I developed my method and process to the way I reload. I can check any of my handholds now and I have none over 0.001". Most are not even measurable. With that said, try this. If you load say 20 rounds. Separate the them into lots based off runout. So say you got 4 that are 0.001" then shoot those together. Then if you have 5 that are say 0.005" then shoot them together. Then you can determine how much your runout is really affecting your load.

Click to expand...

Yes, good idea, but difficult when running up a powder ladder with three shots per powder to see what the barrel likes. However, how are you getting majority of your bullet runout down to .001 or nothing? What did you do to correct? Thanks

Longtine88 said:

Run by my shop sometime and I'll explain it better. I just hate typing long responses on my phone.

Click to expand...

I will, thanks for the invite.

Kmccord said:

What do you believe is the biggest cause for bullet runout, press or dies? I know from experience, I have seen one show very little movement from the Sinclair gauge to have the following to come up with .005 runout, I don't get what is causing it, the sizing die on the neck, seating die or press?? I know it becomes frustrating when developing loads trying to see if it is the reload or the barrel not liking the combo.

Click to expand...

I'd check your cases after resizing them. If you use an expander ball improperly adjusted/ centered can cause case/ neck runout. As far as seating a good fitting seating stem and rotating the case halfway through the seating process helps me. But like Longtine88 said runout isn't always the cause in bad accuracy. Depending on how tight you want your groups to be.

Chamfering with a tool that matches the bullets boattail and trimming (squaring) the necks after each firing helps reduce it too. Neck mouths are never square after firing and sizing. If they are not square it can allow things to tip slightly when the bullet seats.

Barrelnut said:

Chamfering with a tool that matches the bullets boattail and trimming (squaring) the necks after each firing helps reduce it too. Neck mouths are never square after firing and sizing. If they are not square it can allow things to tip slightly when the bullet seats.

Click to expand...

Always trim, chamfer and de-bur.

Well, I get run out too. I've used RCBS and Redding dies and have found the later to be better in this regard. I'll have loads run out .005 to .006 with both of them but I would say this happens in the minority of rounds. I can see where the mandrels and case mouth squaring would help but I don't do that. In any event, I always use a Hornady concentricity gauge to correct everything to at least .002 and sometimes I can get them perfect. I would estimate that I have to correct about 3 to 4 out of 10 rounds loaded.

One thing I think may contribute is slight variance in the contour of the ogive profile. You know how sometimes you have the die set to your CBTO, cases all trimmed uniform and then you get a wacky length measurement? This is probably due to variances in bullet lengths within the lot, I guess. Couldn't the same apply to the ogive?

Oh, and another thing - the concentricity gauge uses a thumb screw to put pressure on the side of the bullet to square it up. Would correcting the run out alter your neck tension? These are all questions that can keep you up at night. Maybe Only the holes we punch can put them to rest.

xsn10s said:

I'd check your cases after resizing them. If you use an expander ball improperly adjusted/ centered can cause case/ neck runout. As far as seating a good fitting seating stem and rotating the case halfway through the seating process helps me. But like Longtine88 said runout isn't always the cause in bad accuracy. Depending on how tight you want your groups to be.

Click to expand...

Forster Dies, have given Me the Least "Run Out" and BEST Accuracy as they Position, the Expander Ball, Near the Top of Case !.
And you can Have them "Honed Out" for, Your exact Neck Tension desired,.. for $20.00 !
I've TRASHED or, Sold, Every other set of, Rifle Dies,.. I've owned !

Roughrice said:

Watching…
I've had the same experience.
Used Redding competition die without expander ball and mandrel…AND Redding FL bushing die with and without expander ball and mandrel.
Seated with Redding competition seater and Lee seater with same results.
It seems to have good runout then a .005 like yours.

Click to expand...

When your reloading for super precise loads what would be an exceptable tolerance? I know I would like to get every one of them to have .0000" runout but I want to be realistic.

Also I picked up a Hornady concentricity gauge which works great for showing bullet runout but I'm skeptical bout using it to force the bullet to be perfectly concentric, I'm not saying it wouldn't straighten everything I just think it would mess with neck tension. What are your thoughts?