Run-out: what do you do?

[frankinaustin]

So I am less than a year into rifle and loading.

Curious what techniques or methods or voodoo spells each of you invoke in order to minimize run-out of seated rounds?

Many thanks!

 

[Mikecr]

Case runout is caused mainly by two things:
- Thickness variance
- Sizing of that thickness variance
The greater of one or the other, or both, the greater the runout.
Lugs out of true, and bad chamber can also create issues here(but rare). Poor bullet seating contributes to higher loaded runout.

I cull cases initially by thickness variance as measured with a ball mic mid necks.
I size minimally across the board, and always expand necks with a mandrel before bullet seating.

 

[Trickymissfit]

Case runout is caused mainly by two things:
- Thickness variance
- Sizing of that thickness variance
The greater of one or the other, or both, the greater the runout.
Lugs out of true, and bad chamber can also create issues here(but rare). Poor bullet seating contributes to higher loaded runout.

I cull cases initially by thickness variance as measured with a ball mic mid necks.
I size minimally across the board, and always expand necks with a mandrel before bullet seating.

Mike; I agree with you 110%, but that also assuming that everything else is good to go. The Poster never stated what kind of run out he was fighting. Two thousandths or twenty thousandths? Are the dies squared up in the press? Is the equipment good to go? I don't care whatkind of a die you use to size cases; if kit's not square you are in trouble. Bad cases make seating useless. So that's where I'd be looking to take at least two thousandths out of the run out. How is he checking the cases and the loaded rounds as well?

Brother inlaw was fighting .0085" with Lee dies and a Lee cast iron press. He brought some cases over to my house and we resized them with my setup. Came in under two thousandths TIR. But on the otherhand I couldn't straiten out the bad ones (only the fired cases). We then went over to his house, and the first thing I did was to square up his sizing die. Got about .0035" run out. He was happy, and I wasn't. I removed the shell holder, and lightly stoned the area it seats on. Found another burr inside the bore. Fixed that, and we were getting .0025" runout. I told him that we'd be lucky to see .004" TIR with the bullet seated. We changed seaters with a Forster I normally use, and was seeing .0033" TIR. Now the problems that are left are in the first operation and the cases themselves. He bought a set of standard Co-Ax dies thinking this was the quick fix. It wasn't! A few days later he dropped by to ask me how the check his press for wear (it was pretty tight). Off we go to his house with a couple .0005" indicators and some other home built tools. His ram was showing about .0018" error, but the top of the ram had a problem. I had him take it into work, and I touched up the top of the ram. I also found out the bore in the bottom was not square with the ram. I set it up and bored that out, and shrank in an inner race from a needle bearing. Then ground it for .0015" clearance. Took another .001" out of the sized cases! He now loads ammo with about .0022" TIR. Funny thing was that while I was rebuilding the ram, he bought a Co-Ax press. It was slightly better, but other than doing the sizing work easier, not much else. Larry did some experimenting with shell holders and saw variance between them, but don't trust his methods.
gary

 

[blacknzr1]

hey tricky... im just wondering what you did to square up the sizing die?

 

[Trickymissfit]

hey tricky... im just wondering what you did to square up the sizing die?

most guys will be doing it with an O frame press, and when I did use one I used the method that Sierra used to have in their manual. But I took it a step further, and put a shim between the base of the die and the shell holder. Loosen the jam nut and run the ram into heavy contact with the die. Then while under pressure, retighten the nut. In my case I used a fender washer that was ground parallel. With the Co-Ax, I made a similar washer, but thicker. The hole is about .50", and the O.D. is close to 1" diameter. The thickness was about .025" thicker than the shell plate. After I reached the size, I removed the shell plate. Then place the washer in place of it, and brought the die down to meet it. Then loosen the nut, and retighten it. The O frame setup is easier, and could probably be done with a piece of shim stock. I might add here that I never trusted the typical shell holder, but saw improvement working off the top just the same.

gary

P.S.; I don't own a Sierra manual anymore, so I don't know if this method is even in there anymore. It came out of a manual published in the mid 1970's. Hornaday doesn't say anything about it, and leaves one to assume the die is square once it's threaded into the frame!

 

[MagnumManiac]

Just had to share, as I looked at this thread, I read the posters name as "Frankenstein", not " Frankinaustin", haha, anyway, when it comes to runout, I have found several techniques that minimise it, but none get rid of it all together. Neck turning helps, but unless you have a chamber with a tight neck, it's probably a waste of time because what's gonna hold the neck concentric to the chamber? The cartridge can move when the firing pin hits putting the neck off centre anyway in a loose factory chamber. I find other techniques in loading good ammo more important than getting really low bullet concentricity, but that's just me!

Cheers.
gun)

 

[frankinaustin]

Thanks everyone. (I'm the orig poster)....

In terms of runout of seated rounds, I experience inconsistency. Which is a puzzle.

On a recent batch of COMPRESSED reloads, about 60% of my seated rounds would have runout at or below .0015 - which is real good. About 20% of my seated rounds would have runout at about .0025. The remaining 20% of my seated rounds would have runout at or over .003. All measured with my digital runout gage from Sinclairs.

The group of reloads with about .0025 runout I was able to "fix" in a crazy way. I fix them by partially beating out the seated bullet with a deloading hammer (kinetic). By that I mean I hit the thing on the garage floor with moderate force until it looks like the bullet has unseated by about 1/8". I then simply run it back through the seating die. Most of the time this method gets my run out to about .0015 or better. However, this never works when runout exceeds .003.

My theory for the reason I'm getting inconsistent runout is that I am reloading a compressed load. (But oh how my rifle loves this compressed load!). Furthermore, when experimenting with reduced recoil loads on a different day (i.e. uncompressed) all my rounds had .0015 runout or better.

I don't have any buddies nearby that handload so I can't "see" what others experience, so I appreciate getting the collective wisdom from everyone.

I'm handloading 7mm-08 in and RCBS Rockcrusher with Forester Dies and a Redding shell holder. Nosler brass. Barnes LRX 145 bullets. And a whole lot of Varget. Love me some Varget!

 

[Canadian Bushman]

It makes a big difference where along the bullet you measure and how long your bullet petrudes from the case. Typically we roll the case and compare the bullets center with the understood center of the case, the further you project this tolerance the worse it appears. I say that because if the case isnt round or true, and even if the head isnt perpendicular sometimes this shows up as runout, and then this awful looking case lines up better in the chamber then it appeared it would.

I think if the majority of your loads run within .002-.003" TIR you are doing really well. I also believe that unless the load is finely tuned and you are shooting for group at a pretty distant target, you wont be able to detect the difference. In my experiments shooting a round that ran out .005-.007" in sequence with a group of cases that ran out .002-.003" i couldnt detect which one was which on the target. This was with my load and my equipment shooting 800-1000 yards with bullets measured halfway between the bearing surface and meplat on a .308 win case with a COAL of 3.2"

 

[brentc]

Just had to share, as I looked at this thread, I read the posters name as "Frankenstein", not " Frankinaustin", haha, anyway, when it comes to runout, I have found several techniques that minimise it, but none get rid of it all together. Neck turning helps, but unless you have a chamber with a tight neck, it's probably a waste of time because what's gonna hold the neck concentric to the chamber? The cartridge can move when the firing pin hits putting the neck off centre anyway in a loose factory chamber. I find other techniques in loading good ammo more important than getting really low bullet concentricity, but that's just me!

Cheers.
gun)

Great point. Don't forget that ejector putting constant pressure to one side of the cartridge base in common push feeds. Also agreed that sound fundamental reloading practices to produce a well tuned load will overcome average runout issues. I don't even bother measuring.

 

[Barrelnut]

It makes a big difference where along the bullet you measure and how long your bullet petrudes from the case. Typically we roll the case and compare the bullets center with the understood center of the case, the further you project this tolerance the worse it appears. I say that because if the case isnt round or true, and even if the head isnt perpendicular sometimes this shows up as runout, and then this awful looking case lines up better in the chamber then it appeared it would.

I think if the majority of your loads run within .002-.003" TIR you are doing really well. I also believe that unless the load is finely tuned and you are shooting for group at a pretty distant target, you wont be able to detect the difference. In my experiments shooting a round that ran out .005-.007" in sequence with a group of cases that ran out .002-.003" i couldnt detect which one was which on the target. This was with my load and my equipment shooting 800-1000 yards with bullets measured halfway between the bearing surface and meplat on a .308 win case with a COAL of 3.2"

Good comment. I would try the exact test CB did and see if the run out you are experiencing even matters before rebuilding a wheel that is working pretty well.

I don't think .003 is really bad. Mine run about .001 to 002.5 with a few crazy ones about .004 to .005