Pardon the lack of detail, I type slow and nobody gives a damn about my data threads so I wont waste much time here. If you have questions ask.

Ok first does the ammo runout? so I made this thing to check it.



I found that there was a lot of run out in the ammo coming out of the the Hornady Mircojust Seating die. I tried it in the RCBS Rockchuck single stage doing all the tricks in the book, didn't make any difference still run out. This is from sorted LC brass where OD and ID run within .002" runout of each other.


Next question is how does this runout effect group size? I loaded a bunch in my unmodified Hornady Lock-N-Load AP progressive  press as seen here.


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I indicated all of the rounds and separated them by runout and colored the projectiles based on runout, then placed them in my ammo boxes in an unknown random order so I didn't know which was which as seen here.



I loaded my mags with the color in the same order (1 red, 1 green, 1 orange, 1 purple and so on) not knowing what round was what.

I fired round robin style so conditions were the same for all groups. All groups are 7 shot groups unless otherwise noted, all shots were with me not knowing what round I was firing. The three target were done on three separate trips over three weeks. All fired prone on bipod from my Rem700 SPS Tactical










I considered .004" runout and under to show little difference overall and .005" and over to be unwanted for good groups.

Averaging group sizes

.001"-.004" runout(12  groups 77rounds) 0.686moa

.005"-.013" runout(10 groups 70 rounds) 1.211moa


So runout matters even with an off the shelf factory bolt gun.



Next question is where does the runout come from? Well true brass comes out of the gun still true and true brass comes out of the RCBS standard sizing die true as well so the problem is with seating.

I indicated many more rounds but below are the groups I did the statistic on. The trend was obvious on all.

The Hornady seater with true brass
85 rounds indicated
AVG RUNOUT= .0045"
STANDARD DEV. =.0025"
60%(roughly) were over .004" runout maybe 25% over .007" and maybe 5% had runout of .009"-.013" .


The Forster seater with true brass
103 rounds indicated
AVG RUNOUT= .0029"
STANDARD DEV. =.0013"
5%(roughly) were over .004" runout  and none over .0065"



Even with bad brass that the ID ranout .005"-.010" the Forster die seated the bullet s straighter than the Hornady with true brass.
over 40 rounds I check avg runout was .0039" with a .002" SD  only 10 were over .004" and none over .008"



I would bet the Redding turns out good ammo too because it is of the same design, but I have read of problems with the seater splitting, the Forster is cheaper, I can find no complaints and has this nice red box that fits the die even with the LNL bushing.



I didn't set the die up as instructed because I am just barely seating the bullet with the bullet feeder die and allowing the Forster/Hornady seating die do all the work. Doing it this way the Forster had to be installed much higher so the in coming high set bullet doesn't hit the sleeve as the plate rotates. There is still spring tension on the sleeve and the sleeve still goes all the way to the base so I don't think that effect function at all.


My press uses the wire case ejector and the sleeve did hit the wire so rather than turning down the sleeve to clear I just put it back one location, the seating at this "flexier" location ranges over .001" the Hornady at a more solid location was +/-.001", so the Forster is even better with consistant depths which I didn't expect.




Forgot to add:

Factory barreled action Rem700 SPS Tactical 20" 1:12 twist (the dreaded "RR" prefix)
Torqued into a H-S Precision stock PSV096 I think(no bedding, Al bedding block)
Drop-in H-S P  DBM kit
Jewell trigger 12oz

175gr SMK
45gr W748(allowing me to load on the auto progressive press thanks to great metering)
LC11 brass(55.55gn h2o cap) some13x some 14x fired(trim/cham/deburred with the lovely and talented Giruad trimmer)
Fed210M primers (pushed in with the RCBS Universal Hand primer)
Seated to roughly 2.845"(actually I don't pay attention to OAL I go by base to ogive but that would be nearly meaningless to you)



Not from today, this is of the 1000yd platform at a range that got sold  recently

Is this with normal brass or was the brass "match prep"?

For the groups, wanting a range of runout, I used normal Lake City 7.62x51 2011. The neck ID to shoulder/body/neck OD runout range from .001"-.010". All the groups fired were loaded with the Hornady die.

For checking the difference between the dies I used the same family of LC brass, but only used brass that had less than .003" neck ID to shoulder/body/neck OD runout. It is all Just surp pull down brass now about 14x fired, pockets uniformed, trimmed,cham, deburred, flash holes.

Cool. Good info.

Great write up, but I believe the more surprising take on this is the 14x fired brass.

Well I lost 10 cases out of 66 fired today due to bad stretch marks, soon to be head separations. I anneal every 5 firings so the necks have been holding up well.

And you are running these in your Rem 700 SPS Tactical with a factory bbl, or your gas gun?

I'm thinking that is a fair statistic regardless.

I use Forster seating dies for .223 and 6.5 Grendel, I like them.

Rem 700 SPS Tactical with factory bbl(non-AAC)

Ha, yes Forster not Forester. I get annoyed when people say Hornaday.



I should clarify the reason I think this and the Redding dies will make straighter ammo. The key is the spring loaded, close tolerance sleeve that goes all the way to the bottom of the case. It forces the bullet to seat in line with the OD of the case body. It even makes straight ammo out of crooked cases.

The big deal is not really the average runout, the big deal is that odds of the higher runout being eliminated are great.


To think of all the odd group results I have had during load development. Well get a few of these crooked rounds mixed in and you will really mess up your groups. I have been working on 210gr Bergers seated 3.100"OAL and I will get great groups but some will turn to shit, I thought my 12 twist may not be stabilizing them but with the shallow seating depth I bet they runout something fierce, I am looking forward to revisit that load and also the 230gr Bergers I have on the way.

Aside from a good load this is the single greatest thing I have done to improve groups. All the case prep and care taken went unnoticed really. Now on a custom gun that shoots sub 1/2moa groups regularly, all the little details may show up more but with my gun and skill it all didn't matter whether I did it or not.

Glen Zediker said a bullet has to start straight to shoot straight, which makes perfect sense, but I thought after traveling down the barrel that would work itself out.
Might be interesting to see if there is velocity loss with higher runout...

I think the crooked bullet swages into rifling crooked once it has formed that way there is no fixing it. It will leave the barrel imbalanced with the point cork screwing.

I chronied all of the first target(64 rounds IIRC) with my Magnetospeed and came up with a 12fps SD and 40fps ES, that is not bad about what I normally get but I have nothing to compare since I have always been shooting crooked ammo. I chrony every time so I will see. Maybe next time I will do groups of runout vs true just for chrony data I will try the PressureTrace as well to see if there is any difference in chamber pressure, I doubt it but.....



I was really skeptical that this would make any difference on anything but a trued gun with a quality barrel and spewed bullshit to that effect, but I was really wrong. I am glad I looked into it farther rather than just dismissing it. I would rather learn something new and beneficial than be right.



On an interesting side note(to me anyway), the rounds fired today make for 825 rounds since I cleaned the barrel(3740 total). I have done bolt maint. every couple hundred and mopped the chamber a couple times. I am afraid to touch now it is shooting so well but I normally clean around 4-500 rounds. Screw it, I'll run it until the accuracy goes before I clean. I have a new Bartlein sitting here for when this one goes so if my lack of cleaning has a negative effect(doubtful), no biggie.

Well your exercise jives with what my friendly gunsmith always said to me.  You can read all the stuff online, in the magazines, and in books and buy into the theories but if you don't actually load up and test them then you know nothing until you do and prove it to yourself.  

There's a lot of truth to that.  

Nice write up.

What variation do you have in neck wall thickness?

Super nice write up. Thanks for your work!

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Back 9-10 firings ago I sorted into two groups measuring with a tube micrometer. One group was .0015" and under(max was .0135"-.015" thick side to thin) and the rest was over. The worst neck wall thickness variance of this 500 case batch of LC was around .006".

I have a lot more indicating to do but right now that doesn't seem to make much difference with this seating die because even the bad group of brass made straighter ammo than the Hornady die did with good brass under .0015"variation. I am thinking indicating neck IDs may be a better method but I have a lot more to check before determining that because it doesn't really make sense

One thing though if you have a tight neck chamber that neck inconsistency may cause problems, but in this case you are probably already turning necks.
 I assume my rounds are centering themselves as the shoulder wedges into its mating chamber surface leaving the case neck hanging out in space touching nothing. I size to zero headspace(I call it) It comes out of the gun at .026"(reference number, not actual) after sizing it is about the same maybe .027" so there is a very slight positive force against closing the bolt which I want to best center the round in the bore and limit case stretching(keep those lugs greased).

Yeah, I just measured, loaded rounds are 0.337" neck diameter, coming out of the gun fired the necks are 0.3455" so the necks have a lot of clearance, maybe .010". So they likely hang out in space.

Thanks for doing that.

I noticed tighter groups when I started using the Forster seating die. Going to replace all my seating dies with one now.

Even noticed my AR loads got better grouping with 77 smk's.

I should also add the method I use to check runout is going to show more runout than most of the methods I see with the other gages. I am checking out at the tip of the bullet where it will runout will be exaggerated. If I indicate a round at the point the bullet seater make a mark( I do for referencing each time) it will show .0055" runout, if I indicate near the case mouth like I see everyone doing in the videos/pictures then it will read .0035" runout.

These factors always make me wonder how much this matters in semi-autos, more disturbance to the cartridge from mag to chamber and all. ..
I'll still use the Forster seating die when I expect the best results but
In a bolt gun, that would surely provide a more even measuring stick.

Yeah, if you are bumping the shoulder back .005" to be sure of proper function I don't believe runout will be as big of a factor in a semiauto(read "but could be some notable detriment"), what will be holding the round centered in the chamber?
Someone had mentioned in another thread that the firing pin pushes the round into the chamber basically centering it. I don't believe that, isn't the extractor preventing this, maybe there is enough room, but I think the primer will dent before the whole round would be pushed forward. Kind of like shooting an animal with a 12ga doesn't send them flying 20 feet like in a movie.

Of course I didn't think this die would make a damn bit of difference I my case either so I could be wrong

I always wondered about bullet alignment and effect on accuracy and this is the first time I've seen anything regarding it. I'm impressed you developed your own study to blind test for unbiased data. Thanks for going through your results/analysis and posting it up.

It looks like you should load to .0004 as it's your most accurate.

I've done similar test 20 years ago.

I didn't have micrometer type deal but just made bullets crooked.  

Results were similar but more dramatic.

I agree, the gun seemed to prefer that area over the lowest runout rounds. Need more data, I have a group of about 45 rounds that are .0035-.0045" that I am going to try next weekend.

I will admit on the middle target with 8 groups I should have quit before the last round, I had bad trigger pulls on 3 or so of the groups, hard to concentrate that many shot(IIRC it was the 6,4 and 9, the 4 would have been unchanged but the 6 and 9 would have been much better).

 I was thinking about just going by the ATC(average to center) moa numbers(shown) because those may be a more accurate representation of the group trend when I have this many groups, rather than judging my mistakes as well. I mean 6 shots in a half inch and then one an inch from that I would say one could assume it is more likely a half inch group load not a 1.250" group if one were to repeat it over and over. It is not really about a specific group size but more about what all of them together show.

Rocketman said in his statistics thread I could output the locations from OnTarget to Excel and it would tell me the standard deviations which would be the best method IMO but I couldn't get it to work.

Awesome write up popnfresh, I enjoy your experiements (even the long ones you think no one reads).

Your results pretty much confirm US Army testing that concluded .003" run-out or less does not degrade accuracy. You don't need flat-liners get excellent results.

If you want some numbers crunched, I would be happy to help since I also dig reading your posts. I am not sure what didn't work for you, but if there is something you would like analyzed, just send me your numbers and I'll take care of it.

I was under the impression I could just paste the text output coordinates from OnTarget into Excel(I know it was slightly more involved) and it would tell me the SDs. I couldn't get that to happen. I pasted them in, pushed some buttons, clicked some tabs but it pretty much just stared back at me as if I was an idiot..hurt my feeling a bit. So I plotted the shots out in my CAD program then measured each distance from the center of the group, took those distances and put them into an online SD calculator. It works but is very time consuming especially doing it for 21 groups.


I would prefer to learn it myself, rather than bother someone else. But it really isn't important enough to spend hours on it or take a class.

Ok, now I think I see your issue.

If you want to take a column of data from some text output, and drop it into Excel so you can run the numbers, then you have to get the data formatted into the cells as numbers and not just text.

When you do a copy-paste, the way you paste in the numbers could be your issue. A menu for converting CSV (comma separated values) to numbers in cells, should pop up for you depending on the version of Excel you are running.

Rather than write in general, I will see if I have any numbers in my old OnTarget files and plow through to the point of getting them into cells so that Excel will run like it is supposed to.



I assume you wanted to take X-Y data from the centroid that OnTarget reduced from one of your sessions, then manipulate that data with Excel. Is that what you wanted to do?

I will say right up front.... I also read your posts Popnfresh.... and no offense intended at all, but they are so through, I am not ever sure what to say !

I have felt that runout and neck tension play a much larger role in accuracy than ES and SD for a long time... but since chrono data was easier to check than neck release and runout.... people put merit in what they could see. I have seen way to many high ES / SD loads shoot well and vice-versa.

Anyhow.... I don't want to change the subject at hand.

Very interesting results. Runout does matter.... I took some IMI Razor ammo and with my Hornady Ammunition Concentricity Tool I "adjusted" the runout and then fired 100yd groups again.... the fliers were no where near what they had been . The fliers tightened up by about a 1/2 "....Now I had no proof that the runout directly helped group size, but it sure looked like it did.

Your thread helps confirm my thoughts.

Particularly interesting your rounds between cleaning.... my M21 loses accuracy after about 150 rounds. A good cleaning brings it back... but I would love to have your count.


BTW , I also tumble my loaded ammo.... I dry vibratory cleaned a bunch of nasty ratty 5.56 Guat. not a single issue. Thanks for clarifying that question also.

That is a LOT of neck clearance.
I have a Berger built live varmint rifle with tight necks on all the barrels.
Tight enough factory cannot chamber.
I turn to a clearance of right around 0.002.

It is scary accurate.

Good enough to change barrels, dial in the offset for the new barrel and shoot under 1/4 inch at 100 yards.

350 to 450 yard groundhog shots are not uncommon.
Find them, range them, hold over or dial in drop.

Don't know how I missed this until now. Nice work! If you'll share your data with me (even the raw text files), I'll be happy to put them into excel format for you, and see what conclusions we can draw. Sent you an IM.

I have Excel 2002 , my knowledge of it is pretty weak. I only use it for making range cards and thread milling programs where some witch doctor made a thingy that I input that variables and it some how(magic I am guessing) tells me what I need to know.

I will give the text files to Rocketman since he can use the info in his statistics thread.

Maybe when we get a better view of it there will be a different outcome.......I may have to alter my overconfident thread title

Glad you/we were able to finally convince yourself that run out might make a difference even in a gun that isn't shooting 1/4 moa  

1/4

Thank you for the experiment in all seriousness, it is nice to see real shooting results .... and we know it takes time and attention to do so.   Thank you for taking the time and sharing...haven't seen it compared this way before...thank you!.

Side note:  Nice tool you made to roll/measure with!

Yep, like I said earlier I would rather learn something than be right, but someone telling me so with no supporting evidence isn't going to convince me. Though I am still not convinced there will as great a difference in a gas gun with a lot of clearance for function as I explained a few posts back. I don't own one accurate enough to test on.

I can do testing with my gas gun (LR308 custom), it's plenty accurate. Someday

ETA: I'll get this into my stats thread and cross post results/conclusions here when I get the chance...probably later this week at the earliest, finishing up some grant applications that are beating the hell out of me ATM

Ditto.

popnfresh, does the one you have have a spring inside, I just got a benchrest seater and it has one

Noob Question: What exactly is "run-out"?

Is it caused by the seating die expanding the neck of the case?

I, too appreciate constructive threads like this.

Based on your thread I purchased a .308 Forster seating die and just ran 20 rounds of .308 - 8208XBR, 155 AMax, 2.8", Hornady Match 1x annealed, WLP in loads of 42, 42.5,43 and 43.5, five each.

I don't have the ability to measure run out, but can say after chasing depth with a Hornady die and getting slight variations, this one is remarkably repeatable and very easy to adjust.  The dial is actually useful for micro adjustments.  One thing that helps is the large gap between .001 increments.  It can also be zeroed.

Before I got the die I loaded some 308 168 Sierra Match King with Re-15 and some with Varget.  I know how these loads group.  I'll shoot them and then load the same load with the Forster die to see if groupings go down in size - not scientific, but I am interested.

I'm impressed.  So much so that I just order the .223 die.  I really can't believe I didn't see this die before, it would have saved me some money and frustration. (Not knocking the Hornady die, just stating that this one is more precise and less frustrating)

Thanks.

Here is a taste, but not the whole story.
Brass and brass prep play a role, and so do the seaters.

http://riflemansjournal.blogspot.com/2009/09/reloading-seating-die-runout.html
http://riflemansjournal.blogspot.com/2010/04/reloading-concentricity-tools.html
http://riflemansjournal.blogspot.com/2009/07/reloading-audette-neco-case-checker.html

If you read these and still have questions, come back.

So if I am now understanding correctly...you don't think there will be as great a difference in accuracy issues when firing ammo with run out issues in a gas gun with a lot of clearance as there is in an extremely accurate rifle?....  do I have that right?

ok....I will go there again... in my opinion which means nothing.....

No offense intended.    But if I have the remaining confusion defined correctly....you don't need an accurate rifle to test your hypothesis that run out issues mean nothing unless fired in an acutely accurate rifle.....or that they certainly won't make a noticeable difference in a  "gas gun with a lot of clearance" .... you actually only need a run of the mill spec loose gas gun right?

Seriously...and no offense intended....but again, just for a second consider this.   What gun to you think stands the best chance of overcoming run out issues better?....a "good" one or a "bad" one?.   Without a doubt (in my mind) ..the answer is a "good" one will better cover some of the issue.

Or put another way....What rifle stands the best chance of overcoming run out issues better? ....one that is hypothetically capable of shooting your pre defined 1/4 MOA ... or one that shoots 2 moa?.   Without a doubt (in my mind)...the answer is the better rifle stands a better chance of covering some of the run out issues.

Respectfully....It is complete opposite of the way you started thinking about this and your initial test already began to prove it...one might just want to think about what the initial test might have already really proved when thinking about the loose gas gun.  

I look forward to the rediscovery (at least I think it would be rediscovery....Harold Vaughn maybe for one?? can't remember)  that run out problems actually perpetuate more (IE not less) accuracy problems in so call "loose" rifles compared to so called "tight" ones....and if it was him...he was a bit of a numbers guy......but you are going to want to use a loose gas gun apparently to prove it to yourself......another learning opportunity if you want to test it - I certainly wouldn't take my word for it   ...I just hope not much new money is thrown at it unless the money is truly disposable .  

Not to get too far away from the allowed path.....I am just going to put it to rest for me by respectfully saying that run out sometime matters to me for my purposes....but it doesn't matter to everyone for theirs ...there is some confusion around the topic....some of it might be mine.....and that's cool by me.  

EDIT for the following


Some more info  (chart here)  to grind on  (American rifleman

These plus Vaughn maybe??   I'm going to try and be done on this one

No you don't have that right. I am thinking the improvement wont be as a much and may be lost in group size variation. If the gun is good for 1.5moa groups everytime then a half moa improvement would be noticed.
If the gun is making groups that range from 1moa to 2moa and only gains 1/4moa then the improvement may go unnoticed. I think the improvement would be less in a looser gas gun than a tight bolt gun. The previous thread you quoted from was about a standard AR platform.

The Hornady does not the Forster does.

This.  Solid work right there.



 

Good info. Thank you popnfresh



In my own words, it's a measurement of the amount of wobble or crookedness of a rotating object.

Picture a drill bit put in a chuck at a slight angle(not perfectly inline with the axis)
Now when you pull the trigger your drill bit wobbles around instead of spinning in a nice tight circle.
Same concept, just think of the chuck as the brass and the bit as the bullet.

Excellent post.  Strongly makes me look into buying the Forster dies.

excellent post very informative.

i have switched most of my seaters over to forster or whidden for the same reason, i didn't measure my run out but as has been mentioned i get more consistent seating depths and accuracy has improved.

nice to see someone spent the time to document the data. Thank you

In spite of the thread title, results may vary. Maybe you are already making concentric ammo.

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I am wondering if checking run out on a gas gun is even worth it. I would like to see how run out is affected after a round is stripped from a magazine and chambered. I would be willing to bet that run out increases considerably.

Vince