Case Prep and Seating for Preventing Runout

[atlsniper6.5]

Howdy Friends,

I'd like to hear everyone's process for minimizing bullet runout for long range. Obviously you want to start with a great set of dies... and then...


Sent from my iPhone using Tapatalk

 

[918v]

You don't need a great set of dies.

What you need is to use dies that will create a straight, stress-free neck tunnel. That way, any seater will seat the bullet with minimal runout.

A conventional sizer die oversizes the neck. This also over stresses the neck. It produces a warped neck. Bushing dies size the neck less, but they still induce runout because they push the uneven neck wall thickness back inside the neck. The expander ball is unable to correct this. You can turn necks, but that induces doughnuts at the neck-shoulder.

I use a Redding body die and a Lee collet neck die to prep the cases. The body die does not work the neck. The collet neck die compresses the neck wall around a mandrel which keeps all the uneven thickness on the outside of the case. Bullets seat straight with any seater.

 

[flashhole]

An early step is to measure the neck runout before you start the loading process. I find runout at this stage to be associated with the difference in neck wall thickness. You can sort the brass into uniform batches or neck turn the brass for uniformity.

When sizing, tighten the die after a you run a case up into the die. This helps the press and die to self align. I like the Lee O-ring die rings as they provide a bit of give.

Use a good seat die that provides axial alignment of the bullet to the case.

 

[greggrissom]

that's the best and easiestidea I have read yet

 

[atlsniper6.5]

918v,
Thanks for the info. I had not done any research on the Lee Collet dies, but it looks like a really cool design that makes a lot of sense. Just curious... Can you do anything to control neck tension with it?

 

[Deadshot2]

Over the years I've found a system that produces extremely "straight" ammo with incredibly low total run out readings, sometimes barely enough to be seen on the indicator dial.

I don't waste any time on new brass. It gets one firing before I do anything to it at all. After the first firing I trim to desired length then turn the necks so the tool cuts the worst cases about 3/4 of the way around the case neck, max. All other cases in the batch are then turned to this thickness.

I full length size all my brass, using a Forster Bench Rest F/L sizing die that has been adjusted using a case gauge so I don't "over size" the case and end up with more headspace than is necessary.

Seating is done with a Forster Micrometer seating die that uses a "sliding chamber" to hold the case while the bullet is held in a separate "sleeve".

My rifle has a "no turn chamber" but I turn the case necks anyway, just to "knock off the bumps". You can't expect the finished cartridge have little or no run out when measured at the bullet if the case necks themselves aren't uniform in thickness although you can get pretty darn close if you use the Lee Collet die and neck size only. This die forms the interior of the case neck around a mandrel. Doesn't help though if the lack of uniformity of the case isn't dealt with an the case is held in the chamber crooked.

Now for the big question? How much does a small error in concentricity contribute to lack of accuracy? More than that caused by the shooter????

 

[atlsniper6.5]

Thanks, flashhole. Do you use an O-ring on your sizing die as well?

 

[atlsniper6.5]

Deadshot2,
Are you using Lapua brass? I have a no turn chamber as well because my smith said I would need it if I use the Lapua stuff. I have never turned it, but I'm wondering if I should to "knock off the bumps" like you said. How much do you normally take off when you turn them?

 

[flashhole]

Thanks, flashhole. Do you use an O-ring on your sizing die as well?

I do and I clamp them down tight using only my hand, no wrench.

The Lee Collet Neck Die works great but it takes a bit of trial and error to get the full benefit It's easy to over-pressure the ram stroke. If you are getting vertical lines in the case neck from the flutes in the collet you are being too aggressive with the die.

 

[918v]

918v,
Thanks for the info. I had not done any research on the Lee Collet dies, but it looks like a really cool design that makes a lot of sense. Just curious... Can you do anything to control neck tension with it?

No.

You could turn the mandrel down to get more tension, but the "as is" tension afforded by this die is good. Not too much, not too little.

 

[918v]

I do and I clamp them down tight using only my hand, no wrench.

The Lee Collet Neck Die works great but it takes a bit of trial and error to get the full benefit It's easy to over-pressure the ram stroke. If you are getting vertical lines in the case neck from the flutes in the collet you are being too aggressive with the die.

If you follow Lee instructions it takes a lot of trial and error. If you follow 918v instructions it takes no trial and no error.

 

[SPAK]

start with a good chamber. If that's out of round all else is futile.

1. Sort brass by neck thickness. Anything over .002" in variance gets put aside. I use them as "B" cases.

2. I turn the necks for about a 75% clean up is all.

3. Load and Fire. I don't even bother to measure run out until after the first firing.

3. full length sizing with the neck honed out to what I desire the neck tension to be. Bushing dies do almost the same thing except most bushing dies won't size all the way to the shoulder. If you're sizing down more than .005" with a bushing die, the chances of increasing runout during this step are higher. I've done both and a FLS die with the neck honed out has yielded better results for me.

Only if i have to iron some dings in the necks I'll run them through a sinclair expander mandrel. I have yet to see this induce any runout at the necks.

4. I prefer to seat with an arbor press and a die cut with my finishing reamer. I've used redding and forster competition seaters and while both do very well at producing straight ammo, I've yet to find either to produce overall better results as far as runout goes than with an arbor press and inline dies cut with the same reamer as the rifle. I know others have had differing results including German Salazar.

5. My TIR on my rounds reads no more than .002" on the worst and 45/50 loaded rounds will read .001" or less on the indicator.

Just what has worked for me….

Whether or not it makes that much of a difference I'm not sure… but I like shooting straight ammo and it's really not all that much work for me to do. I don't do this for all calibers, just the ones I'm particular about.

 

[bigedp51]

If you follow Lee instructions it takes a lot of trial and error. If you follow 918v instructions it takes no trial and no error.

I'm having a psychic vision of your Lee collet die setup with duct tape, string and a torque wrench..............

My press cams over and reaches a mechanical stop with my Lee collet die setup why don't you fill us in on your method.

Read setup by J. Valentine at Benchrest Central
Lee Collet Die Adjustment

 

[Herd Thinner]

Tag

 

[Rangemaster]

Here is what I do to insure no run in the brass.

1) clean the brass
2) anneal the brass
3) use a lee collet die or sizing die with a mandrel
4) check length of brass, trim if too long.
5) check for runout using a Sinclair gage.
6) brass with runout, one pile, brass with .002 or less runout another pile.
7) brass with excessive runout repeat steps 3 to 6

I usually don't see much if any brass with .003 or more runout.

 

[918v]

I'm having a psychic vision of your Lee collet die setup with duct tape, string and a torque wrench..............

My press cams over and reaches a mechanical stop with my Lee collet die setup why don't you fill us in on your method.

Read setup by J. Valentine at Benchrest Central
Lee Collet Die Adjustment

Your imagination is astounding.

But that's not it. I turn the die in way pas the cam over point. It is so far past the cam over point, the press cannot cam over, even with your full weight on the handle.

This, in turn, allows you to feel the case bottom out against the mandrel as you apply pressure. It don't matter if the case wall is .010" or .015" thick.

No need to fiddle with the cam over setting.

 

[Deadshot2]

Deadshot2,
Are you using Lapua brass? I have a no turn chamber as well because my smith said I would need it if I use the Lapua stuff. I have never turned it, but I'm wondering if I should to "knock off the bumps" like you said. How much do you normally take off when you turn them?

There are various "no turn" reamers out there so it's going to depend a lot on which one your rifle was chambered with.

I don't have to turn my Lapua brass but I've found that it too has inconsistent neck thicknesses. Not as bad as other brands but it does benefit from a 'clean up' turn. I turn my Lapua to .014" which gives me at least a 270 degree cut on all cases and a full cut on approximately half.

My Winchester brass get's cut to .012" as it's not as consistent or heavy as the Lapua. I worry less about the neck expansion as some do. I just anneal frequently and get more than enough loadings out of my brass. I have some Lapua that's approaching 20 "cycles" and some Winchester that's right behind it at 15 or so "cycles". I pay close attention to my sizing die setup and make sure it's only bumping the shoulder back a max of .002". This keeps head separation's to almost nil (I've had 3 over the last 6 years and all from cases that were sized too short) as well as shoulder splitting.

I only use Lapua and Winchester brass. Winchester for powders that need more room and Lapua for loads that geneerate more pressure. I do have a few FC cases but I only use those for loads I'll shoot where I will loose the brass. The primer pockets on the Fed's open up too quick so I don't even chase them anymore.

 

[bruddah]

I do and I clamp them down tight using only my hand, no wrench.

The Lee Collet Neck Die works great but it takes a bit of trial and error to get the full benefit It's easy to over-pressure the ram stroke. If you are getting vertical lines in the case neck from the flutes in the collet you are being too aggressive with the die.

Interesting. I get those lines on my .308 brass and did not think I was over aggressive?

Your imagination is astounding.

But that's not it. I turn the die in way pas the cam over point. It is so far past the cam over point, the press cannot cam over, even with your full weight on the handle.

This, in turn, allows you to feel the case bottom out against the mandrel as you apply pressure. It don't matter if the case wall is .010" or .015" thick.

No need to fiddle with the cam over setting.

Isn't there a lot of possible variance or error when doing this by feel as opposed to some way of measure?
It's actually the way I've done it, but it doesn't seem like a real precise way.

 

[918v]

There is no variance as long as the case wall is bottomed out against the mandrel. As long as you can feel this event (the case wall hitting the mandrel) you're good. This is a lot more precise than messing with the die adjustment and risking tearing the aluminum cap out of the die. Remember the press has all of it's leverage in the last quarter inch of stroke and comparatively no leverage where I have the die set. So there is no risk.

 

[jagged77]

If you're get ting vertical lines from the collet try a little case lube.

I set my collet dies up so that the ram fully reaches the top of its stroke. I use a Forster co-ax and this way is 100% repeatable.

 

[Deadshot2]

Interesting. I get those lines on my .308 brass and did not think I was over aggressive?

You're not over aggressive. Those lines are formed as the brass is being compressed on it's way to the mandrel, not after it hits the mandrel. It's a characteristic of a collet, where there are gaps rather than a continuous surface.

I minimize these "lines" by first sizing until I feel the initial sizing coming to an end but before I put the final pressure on the handle. I then lower the ram and rotate the case slightly. This places the jaws of the collet over any line that might have started to form and the result is a uniform case neck. Even on pieces of brass where I don't bother with the second step it doesn't make any difference in performance. Only time it might be a problem is if you neck turn your cases more than once in their life and then you'll have a series of bumps to cut off.

(Note: When moving the case for a "second squeeze", make sure you DON'T turn it 90 or 180 degrees. 45 degrees will assure that you don't just do the second sizing with the collet gaps aligned with the ridges and they're not flattened)

 

[flashhole]

"Isn't there a lot of possible variance or error when doing this by feel as opposed to some way of measure?"

There is. The Lee Classic presses have a mechanical stop on the linkage that allows you to raise the ram until it hits the stop. I get better control using the mechanical stop with the Lee press compared to my Ultramag that cams over.

In the end it's all about technique and what works best for you.

 

[bruddah]

Good info.

 

[catchemall447]

When resizing I Run the brass thru 3 times rotating the cartridge 120 deg before the second and third stroke; couldnt determine a lot of difference. Obtained an RCBS comp. die; no difference; obtained a redding micro head no difference; obtained a Redding seating die to use with the micro head no difference; Voila !! obtained a Forster comp seat die; runout now is one tick mark on Hornady CONCENTRICITY GUAGE; OR .00005.
Couldnt believe it; Just loaded 30 rounds and checked each round; its right on one tick mark .001.

 

[GreggNY]

Tag to come back to the lee collet instructions...

 

[flashhole]

One thing I do when adjusting the Lee Collet Neck Die - I keep a bevel base bullet handy and use it to do a quick fit check to the brass. You can also measure the ID of the neck during die adjustment ... size, measure ... repeat. Keep in mind you'll never get the neck ID the same dimension as the mandrel in the die.

 

[Deadshot2]

One thing I do when adjusting the Lee Collet Neck Die - I keep a bevel base bullet handy and use it to do a quick fit check to the brass. You can also measure the ID of the neck during die adjustment ... size, measure ... repeat. Keep in mind you'll never get the neck ID the same dimension as the mandrel in the die.

For a more precise measurement check into one of these gauges

Case Mouth and Neck Tension Gage 224/308/312

It's a precision ground gauge that will just barely slip into a properly sized case neck.

I have one of his Primer Pocket Go/No-Go gauges for my Large primer pockets. Great to check for proper swaging of crimped cases and helps weed out loose primer pockets before wasting a primer or cutting into your bolt face.

 

[bruddah]

I do and I clamp them down tight using only my hand, no wrench.

The Lee Collet Neck Die works great but it takes a bit of trial and error to get the full benefit It's easy to over-pressure the ram stroke. If you are getting vertical lines in the case neck from the flutes in the collet you are being too aggressive with the die.

Your imagination is astounding.

But that's not it. I turn the die in way pas the cam over point. It is so far past the cam over point, the press cannot cam over, even with your full weight on the handle.

This, in turn, allows you to feel the case bottom out against the mandrel as you apply pressure. It don't matter if the case wall is .010" or .015" thick.

No need to fiddle with the cam over setting.

For a more precise measurement check into one of these gauges

Case Mouth and Neck Tension Gage 224/308/312

It's a precision ground gauge that will just barely slip into a properly sized case neck.

I have one of his Primer Pocket Go/No-Go gauges for my Large primer pockets. Great to check for proper swaging of crimped cases and helps weed out loose primer pockets before wasting a primer or cutting into your bolt face.

That is cool! I just ordered one! Thanks for the link!

 

[bigedp51]

There is a lot of good information here but remember this, if you full length resize your cases the bullet is being supported by the chamber throat and the rear of the case is supported by the bolt face. When full length resizing the body and neck of the cartridge are not touching the chamber walls and any minimal case misalignment is reduced to nearly zero with the cartridge supported this way.

As long as you can visualize a full length resized cartridge case with the body and neck of the case not touching the chamber walls the word "runout" get smaller.

Even the experts say so

Kevin Thomas predecessor in the Sierra testing lab was the late Jim Hull, and now Kevin is shooting for Team Lapua USA.

Now think about what Jim Hull was saying, "I get my best accuracy when the cartridge case fits the chamber like a rat turd in a violin case" now look at the picture I posted above and think about what is actuallyy touching the chamber.

Now read this by someone who also knew Jim Hull.

The Rifleman's Journal: Reloading: Partial Neck Sizing

"Now the last scenario, a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway."

Germán A. Salazar also knew Jim Hull and has his quote at his webpage "The Rifleman's journal" and what he basically said above was his cases also fit the chamber like a rat turd in a violin case.

 

[bruddah]

There is a lot of good information here but remember this, if you full length resize your cases the bullet is being supported by the chamber throat and the rear of the case is supported by the bolt face. When full length resizing the body and neck of the cartridge are not touching the chamber walls and any minimal case misalignment is reduced to nearly zero with the cartridge supported this way.

As long as you can visualize a full length resized cartridge case with the body and neck of the case not touching the chamber walls the word "runout" get smaller.

Even the experts say so

Kevin Thomas predecessor in the Sierra testing lab was the late Jim Hull, and now Kevin is shooting for Team Lapua USA.

Now think about what Jim Hull was saying, "I get my best accuracy when the cartridge case fits the chamber like a rat turd in a violin case" now look at the picture I posted above and think about what is actuallyy touching the chamber.

Now read this by someone who also knew Jim Hull.

The Rifleman's Journal: Reloading: Partial Neck Sizing

"Now the last scenario, a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway."

Germán A. Salazar also knew Jim Hull and has his quote at his webpage "The Rifleman's journal" and what he basically said above was his cases also fit the chamber like a rat turd in a violin case.

So where does the Lee collet die fit into the scheme of things here? Waste of time?

 

[ZombieMonkey]

Personally, I don't even bother with the collet dies or anything of that sort. A good quality F/L sizing die setup appropriately works well for me and many others.

 

[918v]

The advantage of a collet die over a FL die is that it doesn't work the neck nearly as bad.

A FL die sizes the neck .010" under final diameter, and then opens it back up to give you .002-.003" neck tension.

A Collet Neck Die sizes the neck to final diameter which give you .002" neck tension.

Therefore, the collet works the neck half as much. Less stress to the brass means less warpage and less runout.

 

[Colcalcipherol]

Germán A. Salazar also knew Jim Hull and has his quote at his webpage "The Rifleman's journal" and what he basically said above was his cases also fit the chamber like a rat turd in a violin case.[/QUOTE]

Wouldn't this scenario apply more toward the rounds loaded with the bullet jammed into the lands? Would it also apply to to rounds with a long jump, say .050" or more?

 

[918v]

I don't think it matters much. No one has been able to prove what occurs first: bullet entering the bore, then the neck expanding. Or neck expanding first, then the bullet moving into the bore. Or all this happening at the same time.

The loose case theory proposes that a loose round with runout will allow the throat to align the bullet with the bore because the case can move in the chamber a little, so here is some wiggle room.

In reality, the extractor pushes a loose round against the left side of the chamber. So there is no wiggle room.

But maybe there is: a case sized in a typical sizing die has about .001" of clearance at the base. So even under extractor tension the case isn't too much out of line with the bore center and can still wiggle in the shoulder/neck area.

Unless you consider that case bases often expand unevenly, and one side of the case expands more than the other. So the case neck is always off center.

This runout thing can give people fits!