Bullet runout worse by using an expander mandrel?

[nalye]

First things first: Not a native American, so please excuse any wrongly used words or terms.

My process of reloading .308 Win included (but is not limited to) running the case through my Triebel BR neck sizing die with the expander ball included. This turned out to have an average runout of around 3-5/1000. Of course I thought that this could definitely get better so I watched some videos where they introduced something to me that was praised as the ultimate runout neutralizer: an expanding mandrel.

Quick I went and bought one online, namely this Wilson expanding die.

When I removed the expander ball from my neck sizing die and used the Wilson die afterwards I was curious and checked the runout. It went from an average of 4/1000 to a nice and smooth 75-100/1000.

How on earth could this happen? Did I buy something wrong? I always thought that expanding from above instead of pulling apart the case when expanding is the way to go.

 

[spife7980]

Where and how are you measuring this runout?
If its bullet then is it at the tip or base?
If its neck, are you inside or outside? And depending on that are you factoring the differences in neck material thickness?

It can happen a dozen different ways. Its going to take lots of careful measuring and comparison to identify where and why on your part. (And thats why so many dont bother with runout now, after all that work they cant tell the difference when you put the bullet through the paper)

 

[nalye]

Thanks for your answer.

1) I measure the runout on the bullet ogive close to the neck using the Hornady concentricity tool.
2) The bullet is the Sierra Matchking HPBT 168 grain in .308 Winchester.

I am yet to test the bullets with the large runout, I will do that tomorrow. I was just wondering whether any of you already experienced this phenomena, hence me asking here. It's quite confusing having this large of a difference to be honest.

 

[Cascade Hemi]

I have found mandrels induce more runout. Dies with pull through buttons, like Mighty Armory, induce less. Neck turned brass and custom honed FL die without button is probably best. Lee mandrel die is as close to zero as I've measured.

None of it seems to matter on target.

 

[CK1.0]

None of it seems to matter on target.

This is my experience with runout as well. If it takes fractions of a thou to even measure it, you're fine.

Using the mandrel isn't about runout.

A mandrel doesn't distort the shoulder by pulling up on it in the same way an expander ball does, and it pushes the imperfections from the inside of the neck outward, normalizing the inside diameter.

 

[nalye]

So the consensus seems to be that I do not have to worry about the runout? Tomorrow I'll check and see what the paper says, this is what counts. Thanks to you all who answered.

 

[rmfield]

When I removed the expander ball from my neck sizing die and used the Wilson die afterwards I was curious and checked the runout. It went from an average of 4/1000 to a nice and smooth 75-100/1000.

Hopefully you didn't actually mean 75-100 thousandths. That's a huge number for runout!

 

[Dave62677]

Try use the SAC neck bushing with a good quality bushing die. I run 21st century mandrel after my sized brass to get the proper neck tension. How’s your neck tension force when you seat your bullet? From my experience, the greater the seating force will produce more runout for “my” setup. My runout with SAC bushing + 21st mandrel = 0.001 to the most 0.0025 runout.

There too much variables might lead to your runout - die setup / brass condition / seating force

 

[nalye]

Hopefully you didn't actually mean 75-100 thousandths. That's a huge number for runout!

This is what I meant. Hence the thread asking if this is something to be expected or to worry.

 

[Precision Underground]

This is what I meant. Hence the thread asking of this is something to be expected or to worry.

That’s massive for runout, I’ve never seen anything close to that and I use expanders a lot. Like 8-9k is the max I’ve ever had and 99% of the time I’m at 1-2k. Are you sure it’s the expander doing it? Load 5 with and 5 without and keep everything else the same to see if it is. If it is the expander doing it, I’d guess the mandrel is not seated straight or the die itself is not straight. I float all dies(don’t tighten to a hard stop) to allow the play in the threads to straighten the die when the case presses up on it.

 

[Rover31]

Runout can affect accuracy. The straighter the bullet can engage the bore/riflings will help with alignment down the bore.
Before anyone argues that the bore straightens the bullet… it doesn’t! The “soft” bullet is slammed into the lands (made of hardened steel) at 30-60k of pressure it doesn’t straighten it deforms.
Go look at a .22lr bullet and how it is changed by the little amount of powder behind it.
now that said how much effect does it have? I sure don't know...

Ok now that I have stepped down from my box…
I use a Wilson bushing die and then a Wilson mandrel like you. Your press can have effect on the process. Depends on how well the Ram(holding the case) and die are aligned.

I have had thoughts about how we do the mandrel process. The case is not supported in any manner by the mandrel dies we use. If the case is not engaging the mandrel rod perfectly how can the case mouth and neck remain straight to the body?
This is a problem that I feel needs to be addressed…

Bit of a ramble as I sit here waiting for Costco to open…

 

[Cascade Hemi]

A mandrel doesn't distort the shoulder by pulling up on it in the same way an expander ball does, and it pushes the imperfections from the inside of the neck outward, normalizing the inside diameter.

Did you measure each process and see a difference? On once fired annealed Peterson 6.5CM brass, using a Mighty Armoring die, I can not measure a difference, base to datum, between an unlubed expander and no expander. Both produce about .001" indicated runout at the neck which is easily within the variation of the unturned necks. The only real benefit of the separate mandrel process is diameter control.

 

[CK1.0]

Did you measure each process and see a difference? On once fired annealed Peterson 6.5CM brass, using a Mighty Armoring die, I can not measure a difference, base to datum, between an unlubed expander and no expander. Both produce about .001" indicated runout at the neck which is easily within the variation of the unturned necks. The only real benefit of the separate mandrel process is diameter control.

I don't know if it's because I anneal every firing or what (might be), but I notice a difference using a mandrel for sure versus an expander ball in so far as just better more repeatable overall neck consistency and just better shooting ammo for me. I've never bothered to measure the shoulder datum and compare, so IDK if it measures out any differently.

I tried a Mighty Armory die (in 6CM) because I was curious about Wayne's "mandrel"... and it was probaly better than a classic/standard expander ball but still not the same IMO. YMMV.

 

[Cascade Hemi]

I don't know if it's because I anneal every firing or what (might be), but I notice a difference using a mandrel for sure versus an expander ball in so far as just better more repeatable overall neck consistency and just better shooting ammo for me. I've never bothered to measure the shoulder datum and compare, so IDK if it measures out any differently.

I tried a Mighty Armory die (in 6CM) because I was curious about Wayne's "mandrel"... and it was probaly better than a classic/standard expander ball but still not the same IMO. YMMV.

When I run a .262" expander mandrel into a FL sized case (without expander) I get the same ID as with the native expander, only with about .0005" more runout. There is no difference in ID variation, no difference in base to datum. There is effectively no difference. Again, once fired and annealed brass. I replicated the same results with 308Win (2 fired annealed Lapua brass) and 6GT (2 fired annealed Alpha brass). 308Win with a Forster die, 6GT with a RCBS Matchmaster die, and corresponding mandrels. I have six more cartridges I can test but it would be pointless. The mandrel just adds another step to the sizing process.

 

[CK1.0]

When I run a .262" expander mandrel into a FL sized case (without expander) I get the same ID as with the native expander, only with about .0005" more runout. There is no difference in ID variation, no difference in base to datum. There is effectively no difference. Again, once fired and annealed brass. I replicated the same results with 308Win (2 fired annealed Lapua brass) and 6GT (2 fired annealed Alpha brass). 308Win with a Forster die, 6GT with a RCBS Matchmaster die, and corresponding mandrels. I have six more cartridges I can test but it would be pointless. The mandrel just adds another step to the sizing process.

IDK, I haven't really tried going back to an expander since moving to the mandrel, but I get what you're saying.

It might be something I might try again at some point since it saves a step, but lately, I even feel like I see a difference just by waiting to mandrel until after the lube has been tumbled off and the cases are done getting knocked around.

Plus, I try not to try and fix stuff that ain't broken if the juice isn't worth the squeeze, and the mandrel step is fairly painless and doesn't bother me as much or take as long as many of the other dumb reloading tasks I still have to do every cycle lol.

I'm not as rigid in my methods as some around here are though, I do still change stuff and update my process as I come across ways that work better, or figure out there's been shit I've been doing that's mostly pointless.

 

[Rhed]

Are you using a dry lube before you expand? Like Reddings neck dry lube or similar?

 

[Holliday]

Try use the SAC neck bushing with a good quality bushing die.

I saw reduction in runout switching from the redding titanium nitride bushings to the SAC bushings. It surprised me. Now they are all I use.

 

[Marine52]

So the consensus seems to be that I do not have to worry about the runout? Tomorrow I'll check and see what the paper says, this is what counts. Thanks to you all who answered.

A tenth of an inch runout indicates you are doing something wrong. What brass are you using?
make sure the expander die is not coming down too far and hitting the case mouth. As Rhed said, use a dry lube inside the neck.

 

[Marine52]

Nalye: we are talking about thousandths of an inch right, not millimeter? I know you guys in Germany use the metric system. 100/1000 of a MM translates to about .004 inches which is in the acceptable runout range.

 

[nalye]

A tenth of an inch runout indicates you are doing something wrong. What brass are you using?
make sure the expander die is not coming down too far and hitting the case mouth. As Rhed said, use a dry lube inside the neck.

I am using lube, yes. I think I might Insert the mandrel too far? The mouth does not hit the die but the mandrel is quite fairly down inside the case.

Nalye: we are talking about thousandths of an inch right, not millimeter? I know you guys in Germany use the metric system. 100/1000 of a MM translates to about .004 inches which is in the acceptable runout range.

I set all my tools to the imperial system to avoid this kind of confusion. Metric only for L3 and L6

 

[PB&J.]

It doesn't help your current situation, but in my testing the humble Lee Collet dies have consistently produced the lowest runout for all cartridges I have tried them with. They are now my go to die for final neck sizing.

 

[Rocketvapor]

Can you check neck runout and neck diameter at various steps?
As fired,
Sized with NO button, mandrel,
Sized and expanded,
Seated just enough to hold the projectile,
Fully seated.

I use a body only die for bump that doesn't size the neck at all, then the Lee Collet Die.

 

[nalye]

Okay, I just got back from shooting.
It seems that the runout - at least for this combination - does not really matter. My group was around .75 MOA @100 meters (~110 yards) and the SD was 3.1 mps (~10.17 fps) for the measured 30 rounds.

(all units are non-freedom ones)

Nevertheless, I'll try to have the die 1) floating, i.e. not tightening to the press and 2) not inserting the mandrel deep into the case. I'll get back with the results when this has been changed and tried out.

 

[Cascade Hemi]

Okay, I just got back from shooting.
It seems that the runout - at least for this combination - does not really matter. My group was around .75 MOA @100 meters (~110 yards) and the SD was 3.1 mps (~10.17 fps) for the measured 30 rounds.

(all units are non-freedom ones)

Nevertheless, I'll try to have the die 1) floating, i.e. not tightening to the press and 2) not inserting the mandrel deep into the case. I'll get back with the results when this has been changed and tried out.

Try putting the expander ball back in the die and skipping the mandrel.

 

[nalye]

Sorry, I should have mentioned this: My SD actually decreased, I was at 5-7 mps before, now it's down to 3. The group stayed the same (I am not the best shot yet) so there seems to no real reason to switch back.

 

[lash]

Try putting the expander ball back in the die and skipping the mandrel.

That’s what I ended up doing after trying a separate mandrel. I lightly turned the expander ball on Emory cloth until I got the ID results I needed for a 0.002” fit. This works very well for me.

 

[Cascade Hemi]

That’s what I ended up doing after trying a separate mandrel. I lightly turned the expander ball on Emory cloth until I got the ID results I needed for a 0.002” fit. This works very well for me.

Amazing how an unnecessary process made popular buy a couple of random dudes with a YT channel spread to the other side of the world, isn't it?

 

[ZY100]

Make sure your mandrel die is not set too deep. I.e. the mandrel is not going too far into the case and bottoming out against the case mouth.

 

[MarkyMark007]

How on earth could this happen?

because you read american bullshit. runout doesnt matter. and mandrells are stupid.

if you want better die for neck runout, you can try Forster costum FL die from Henke-online with ~0.002' of neck tension.

 

[MarkyMark007]

Nevertheless, I'll try to have the die 1) floating, i.e. not tightening to the press...

why do you need to have die free-floating? is not your brass free-float? if your brass is free-floating, why do you need also the die free-floating?

 

[Rocketvapor]

I find that if the die is not locked to the plate that repeated sizing pressure on the loose threads tends to walk the die out.

 

[Yondering]

I set all my tools to the imperial system to avoid this kind of confusion. Metric only for L3 and L6

I'm having a REALLY hard time believing your runout measurements, and suspect the most likely answer is you typed the numbers wrong or measured incorrectly.

You're saying runout went from .003"-.005" with an expander ball, to .075"-.100" with a mandrel? That doesn't even seem possible, and I'm not sure how you're getting rounds to chamber with a tenth of an inch of runout; your chamber shouldn't have tolerances that loose. The bullet would be visibly very crooked in the case as well.

Something is drastically wrong with those numbers. If you meant .0075"-.010" that would be believable, or just measured in metric accidentally.

 

[nalye]

Pretty sure I meant .0075"-.010".

 

[SporterII]

Stupid American here. I like using the mandrel. I do not anneal often. I can choose neck tension. I shoot better when satisfied with my work.

 

[acudaowner]

no idea what your doing maybe it's from your bushings but my necks after 9 reloadings are as tight with pin gauges to check as they were on the first firing and I just use the die body to close up the necks to hold a bullet they the expanding mandrel to open them to the tightness I desire ( or looseness )

 

[Yondering]

Pretty sure I meant .0075"-.010".

OK that makes a lot more sense; not 100/1,000" but 10/1,000". (Also a good example why it's easier and clearer to just write .010")

I wonder if what you encountered was a neck lube issue? and are you absolutely sure the case mouth isn't bottoming out in the die? The mandrel doesn't need to go in any futher than the bottom of the neck.

I'm not sure why your results would be so much different, when a mandrel provides less runout for so many others. I'm not doubting the results you got (now that the numbers are corrected), but it'd be interesting and useful to figure out why it made runout worse in your case. What's different?

 

[nalye]

I lubed the neck quite well, so that was not really an issue. I also did not feel the mandrel "scratching" its way downward the neck. In the meantime I did another test by not pushing the case up that much, still it made absolutely no difference. Maybe the mandrel itself is just f'ed up, don't really know. The runout with the mandrel was measured to be between .010 and .025 this time while working 5 cases.
Maybe I'll try another mandrel one day but for now I threw on back the expander ball and I get to work with that.

 

[Cascade Hemi]

How many thread interfaces and $.25 parts are you relying on to get machine perfect concentricity? The mandrel is rigid while the expander ball isn't. I bet if you were to chuck some of those mandrels, and mandrel bodies, in a lathe collet you'd see some runout. The Porter gage pins are the only mandrels I would expect to see zero run out in the pins and even then you still rely on low quality press and die ring threads. Sometimes the mandrels are perfect, sometimes they are pretty far from perfect.

 

[Buzzinga]

After using just about every type of sizing die and combination of mandrels, bushings, etc. I found the good old fashion, cheap, RCBS FL dies with the expander mandrel attached (as it comes from the factory) to be as good or better than dies way more expensive.

 

[Yondering]

I lubed the neck quite well, so that was not really an issue. I also did not feel the mandrel "scratching" its way downward the neck. In the meantime I did another test by not pushing the case up that much, still it made absolutely no difference. Maybe the mandrel itself is just f'ed up, don't really know. The runout with the mandrel was measured to be between .010 and .025 this time while working 5 cases.
Maybe I'll try another mandrel one day but for now I threw on back the expander ball and I get to work with that.

It's quite possible the mandrel itself is crooked, but I wonder if it's actually a burr or machining chip in your mandrel die? Seems easily possible, and forcing a crooked mandrel into your brass could cause what you've described. It could be a burr where the mandrel seats against the inside of the die cap, or the shoulder in the body where the mandrel sets into it.

For expander balls, I really like the little carbide buttons for the Redding dies. I don't have them on most of my dies, but where I do use them, they're just slicker sliding through the case necks.

For volume case prep on a Dillon though, I've been using Lyman M dies, which are really just a mandrel die with a step at the top. That step lets the bullet seat into the case a little and seems to work very well for good concentricity even with high volume progressive loading. Also don't have to chamfer the case mouths when using it. Downside is you can't choose different mandrel sizes like you can with a Sinclair, etc.
NOE bullet molds sells a cheaper alternative to the same thing - it's like a little short mandrel with a step, that fits into the Lee universal expander die body. Same effect as the Lyman, but the Lyman does seem to be a higher quality setup.

Just some random thoughts on mandrels.

 

[Haney]

How many thread interfaces and $.25 parts are you relying on to get machine perfect concentricity? The mandrel is rigid while the expander ball isn't. I bet if you were to chuck some of those mandrels, and mandrel bodies, in a lathe collet you'd see some runout. The Porter gage pins are the only mandrels I would expect to see zero run out in the pins and even then you still rely on low quality press and die ring threads. Sometimes the mandrels are perfect, sometimes they are pretty far from perfect.

I let my shell holder/brass float and my mandrel die float as well . Works just fine .