Run-out problem - source?

Apollo

Apollo

Jason Stanley
I'll make this as quick as I can. I measured some of my loaded rounds for run-out. Found some were close to .005. So I wanted to find out where I was making a mistake. I measured 3 fired cases on my Forester case gauge thinger....essentially zero runout. I then resized these same 3 cases and re-measured. Again, virtually zero runout (dial barely moved - easily under 1/2 thousandth). I then seated a bullet in these 3 same cases 004-.006 runout. So....,I'm guessing, it is either the bullet, die, or measuring device. I'm throwing out the bullet source - cause Randy R. wouldn't mess up like that. Leaning towards the Forester measuring device. However, I use a Wilson Arbor press style seater with a Sinclair micrometer top. I did drop the top off onto the concrete floor and had to "polish" the stem with some 800g black sandpaper to get the burr off of it so it would fit back into the die. It now slides very smooth - however dropping it can't do it any good. Any suggestions on what to check?

Thanks in advance

Stanley
 
Perhaps you polished stem such that it would go into die but it is still deformed in the seating cavity. Ordering yourself a new seater stem would seem like next step to me.
Dick
 
Jason: wrap a thin strip of common Scotch tape around the neck of resized case, seat a bullet and measure the runout. Let us know what you find. -Al
 
I repeated the above procedure - again zero runout on the cases. I made the scotch tape 1 layer thick and the run-out came down to about .003. I'll try again with 2 layers.
 
Cool - learned something tonight. Don't wrap 3 layers of scotch tape around your case neck and try and seat a bullet. It gets stuck in the die. Awesome! Had to pry it out with a pick type device - went to measure the runout after I got it out and discovered that the pick messed up the bottom of the case - had close to .011 runout (new Stanley record)
 
Most 'Scotch' tapes run about .003 in thickness. It appears that reducing the clearance between the neck/die did help the runout somewhat, so you seem be on the right track.
 
The only way I know how to fix adding more material would be to order a new die. :(
I did have this die polished so the case wouldn't stick - however I'm sure it wasn't even close to .003 material removed.

Does jamming the bullet - help take the runout out?
 
If there's enough material ahead of the end of the neck, you can run the chamber reamer into the die and face off the back end a like amount. I'm pretty sure you know someone that could handle that for 'ya? ;)

Yes and no on the jam....... -Al
 
I've found that when the neck is sized down more than .005" at a time we induce runout into the neck. If using bushing dies remove the bushing and size. See if you still get zero runout in the sized case. Your doing the same thing with scotch tape, reducing the amount of clearence between the case neck and neck sizing portion of the die. Try a bushing of a slightly larger size first then your nirmal bushing. That was my fix several years ago until I started chambering my own rifles. My reamers are ordered for no turn necks but only enough clearence for safe firing.
 
It doesn't matter :)

Without you got a tight neck it's immaterial.... the bullet WILL be slammed against the side of the chamber neck before it wriggles into the rifling lands.

One side or t'other, randomly.

You give a butt room to move, it will.

al
 
Both. The cases before the bullet had .0005 After the bullet was seated - the case then showed .004-.006 runout. Same with the bullet when I moved the indicator to the bullet - about 1/2 way on the bullet.
 
A few years ago I checked runout on several brands of seater dies and found that it varied from dead nuts zero to .006. I would suspect the seater.
 
I am assuming this is a 6PPC. If not, please let us know. When measuring the runout of a sized case. Does it measure the same on the outside and inside on the neck? If the runout in both places are acceptable, it's definetly the seater.

Hovis
 
30BR. And I only measured the outside. Is this another positive to inside neck reaming? I don't have a gauge/tool to measure the runout on the inside.
I checked with a guy "who lives in a van down by the river":D to see if he can run the reamer, same one that is used on my new barrel, in the die. Haven't heard back yet.
 
The only positive thing about neck reaming is getting rid of the donut. Once you fireform and/or resize, your runout in your neck wall thickness will always move to the inside (whether neck turning or reaming) as long as your using bushing dies. I can't imagine there would be that much runout on the inside of the neck but sometimes it can surprise you. I still lay the bet on your idea....the dropped seater stem is the culprit.

Hovis
 
"I then seated a bullet in these 3 same cases 004-.006 runout. So....,I'm guessing, it is either the bullet, die, or measuring device."

The combination of a sloppy die bullet chamber AND excessive "bullet tension", which demands excessive pressure to seat bullets, can be guaranteed to produce as much run-out as the die will allow.
 
"I then seated a bullet in these 3 same cases 004-.006 runout. So....,I'm guessing, it is either the bullet, die, or measuring device."

A combination of a sloppy die bullet chamber AND excessive "bullet tension", which demands excessive pressure to seat bullets, can be guaranteed to produce as much run-out as the die will allow.
 
Apollo said:
I did drop the top off onto the concrete floor and had to "polish" the stem with some 800g black sandpaper to get the burr off of it so it would fit back into the die. It now slides very smooth - however dropping it can't do it any good. Any suggestions on what to check?

Thanks in advance

Stanley
Click to expand...
If dropping the stem/top on a concrete floor created a burr that you had to polish off, then it also made a burr in the cone of the stem where it contacts the bullet nose. Check that.
 
JerrySharrett said:
If dropping the stem/top on a concrete floor created a burr that you had to polish off, then it also made a burr in the cone of the stem where it contacts the bullet nose. Check that.
Click to expand...

And its more than likely that the stem is bent if it hit hard enough to deform it.
 
You must log in or register to reply here.
Back
Top