Is there such a thing as a case that causes fliers?

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  • Last Post 27 January 2022
John Alexander posted this 21 November 2021

I have heard and read over the years of shooters trying to eliminate fliers by discarding the cases that shot them.  I'm not talking about cases that have gross variations in neck thickness from one side to the other, oversized primer pockets, or other such know defects, but a case that seems OK but is guilty of being present when a flier was shot. 

Although I have heard of discarding such cases, I have never heard of anybody confirming that the case was guilty by seeing if it would shoot out of the group repeatedly. 

Does anybody know of a shooter confirming that an otherwise normal looking case ruins groups and if so any theories what is wrong with such a case.

John

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OU812 posted this 27 January 2022

Lots of videos on the subject. This author named Bolt Action Reloading has lots of test videos concerning jacketed bullets and F class long range shooting. I gather that bullet fitment inside throat is most important. Loaded round concentricity is OK if under .004"

https://www.youtube.com/c/BoltActionReloading/videos

https://www.youtube.com/c/BoltActionReloading/videos

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BJung posted this 27 January 2022

Maybe. I haven't don't a test to verify my claim but read this article from lasc.com. An exceptionally long or short case might contribute to a handgun flyer

Secrets of reloading for the Colt Combat Commander 9MM auto loader (lasc.us)

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Lee Guthrie posted this 23 January 2022

Think of his diatribe to be more in the nature of "word salad".   His just wasn't as tossed as much as it could have been.

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RicinYakima posted this 20 January 2022

Head not square with the case walls, centerline of the bore.

 

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John Alexander posted this 20 January 2022

I am doing some experimenting on the topic of "bad cases" and in thinking about it could think of these things about A SINGLE CARTRIDGE CASE that might possibly affect group size.

Variation in powder capacity

Variation in neck  wall thickness

Variation in case wall thickness

Variation in neck tension on bullet

Are there other possibilities? Suggestions appreciated.

John

 

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RicinYakima posted this 12 January 2022

Yep Jim Carmichel in an early Handloader. Did the same thing as you did, sort of worked but inconsistent. But you could use smaller measures of faster powder and get OK results when powder went in price from $4 a pound to $8 a pound in the 1970's. 

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shootcast posted this 12 January 2022

We all do things that seem like there should be positive effects. Maybe for some of us there is. If it works or you think it works you will continue to do it. I once read and article that I believe was written by Jim Carmichael. I have never been able to find it so maybe it was someone else. The writer experimented with putting 223 cases inside of 308 cases to effectively reduce case volume. Sounded interesting to me and I tried it also. My outcome was the same as his. Although it worked some small extent or it seemed it did it was not a given. Accuracy on average was no better than using standard 308 cases. Shoot enough groups and occasional you get a dandy.

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John Alexander posted this 11 January 2022

Ken,

Interesting ideas. I always thought that the theory that it caused unequal force on bolt lugs the most promising explanations of all the other theories about why it should help -- but it is still just a theory.  

JB shooters seem just as reluctant as CB shooters to take a day, load some with and some without, and shoot a few groups to find out if the theories we like to think up amount to anything. 

I think the panic over case wall thickness has gone the way of indexing cases with JB shooters. In my close reading of 3 books by top JB benchrest  shooters including Tony B's. I found no advice about uniform case thickness.

I like the idea of minimizing the amount of bullet in the case mouth. Part of John Ardito's success may have been that he throated so that his bullets were barely in the neck. I know he thought so.  It seems even more reasonable for CBs than JBs since CBs are much softer. I have tried to design bullets for factory throats so not much more than the gas check is in the case but haven't got it right yet but throat erasion is helping get closer.

John

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John Alexander posted this 11 January 2022

45 2.1,

Thank you.

John

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45 2.1 posted this 11 January 2022

So -- why don't you reveal what Martin found?  What happened after he turned the walls to uniform thickness? That would be helpful instead of just a cryptic shot.  I'm sure that very few of our readers have a file of Merril Martin articles at their fingertips. 

John

I said it's been a long time. Someone (on another forum) got permission to post Merril's write-up from him with pictures and all. I remember the pictures and somewhat of the results (that being it was favorable for him). I don't have any files of his as I didn't take Precision shooting. At the time, I had worked out something else and had no need of his method. If you want more, then you'll have to look it up.

 

 

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Ken Campbell Iowa posted this 11 January 2022

i understood the brass case wall thickness difference to affect >>

the way the case head affected the bolt face .... one lug being struck harder than the other from case head impact ...and thus.>

the vibration of the gun and thus where the barrel pointed at barrel exit.

***************

seems silly but then i recall a popular improvement for Remmy 700 actions is to install an oversize bolt ($500)  so it can be " blueprinted " tight and true to the locking lugs and chamber.

and even some cheep-arse crutch fixes that involved brass shimming the rear of the bolt body and also just installing a cap screw through the top of the rear ring to keep the back of the bolt from tilting as the cartridge is fired. ( and maybe because of the trigger design ) ...

**************

could be ... from my 22rf and barrel tuner days i BELIEVE in those vibration conspiracy theories ... we could get a 1 to 3 group size difference by moving the tuner ...   

refer to Dan Lilja's little notes on action movement at the shot .. it does stretch due to rear force on the lugs.   will a thin case wall push one bolt lug more than the other ??? ... LEMME SEE THE TARGET !! ...


**********************

finally, ... some of my midwest hero MJ benchresters are having success with a chambering where there is almost no case neck ... the idea is that the bullet is located really well by the case tapered shoulder ... this seems really interesting ...  if the case neck is such a nuisance, just get rid of it ! ...  

of course, about the same idea would be to run loose case necks and seat the bullet in that loose neck with some post-it note glue ... rubber cement.....

i gotta stop, i'm killing myself ...  ken

 

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John Alexander posted this 11 January 2022

So -- why don't you reveal what Martin found?  What happened after he turned the walls to uniform thickness? That would be helpful instead of just a cryptic shot.  I'm sure that very few of our readers have a file of Merril Martin articles at their fingertips. 

John

 

 

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45 2.1 posted this 11 January 2022

Until someone performs an experiment similar to Paul's that shows that there is a correlation between uniformity of case wall thickness and accuracy, we have Paul's results versus a lot of hot air.   John

It's been a long time, but Merril Martin did this exact thing in a 30-06 cast bullet match rifle by turning the case body's walls to uniform thickness. Look it up yourself in Precision Shooting.

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OU812 posted this 11 January 2022

Most everything from Cast Boolits is hot air I think.

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John Alexander posted this 11 January 2022

The situation inside the case as the bullet is starting to move is surely far more complicated that a static pressure situation. There is bound to be the pressure waves you mentioned in addition to tremendous turbulence for any shape case. This state of unpredictable chaos seems even more reason to be skeptical that a 0.003" difference in wall thickness could possibly affect the pressure on the base of the bullet. Our opinions may differ on this but neither opinion makes a whit of difference.

Until someone performs an experiment similar to Paul's that shows that there is a correlation between uniformity of case wall thickness and accuracy, we have Paul's results versus a lot of hot air.

John

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freebullet posted this 11 January 2022

In my experience those cases with neck thickness issues will cause fliers.

I don't waste time turning necks for that issue because it was explained that variation runs the length of the case. Turning the neck doesn't correct the rest of the case. The book explains it like a banana shaped case. Makes sense to me it wouldn't heat or respond to heat/pressure the same.

Since following that advise helped, I haven't looked back. Ymmv

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45 2.1 posted this 10 January 2022

 

 In this case anybody who had paid attention in high school physics would have known that gas in a closed container i.e. case, exerts pressure equally in all directions.  Thus the pressure on the base of the bullet wouldn't be affected by the shape or size of the case. And thinking that the case body needed to be concentric with the bullet base is beyond all reason.

.John

The lab guys tell us that those pressure waves rebound back and forth inside the case. A very dynamic situation. What does that behavior do to a non concentric case, let alone steep shoulders on the case?

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John Alexander posted this 10 January 2022

Paul,

Outstanding! There is nothing wrong with your shooting or your analysis.  First rate experiment with a side benefit of taking a look at the precision of fouling shots.

Some time ago the jacketed bullet benchrest community had their collective knickers in a twist over non uniform case wall thickness. Theories were ginned up about all the bad things that might be caused by such case defects. All this speculation and angst was dully reported in their journal "Precision Shooting".  A ton of high priced case wall thickness measuring devices were sold. Shooters were indexing cases so the fat side was always on top or bottom when chambered. NOT ONCE did I see a report like yours of a logical designed experiment to confirm or refute the theories.

That silliness is a prime example of what happens when we try to reason up a theory about shooting without making sure our assumptions are correct. In this case anybody who had paid attention in high school physics would have known that gas in a closed container i.e. case, exerts pressure equally in all directions.  Thus the pressure on the base of the bullet wouldn't be affected by the shape or size of the case. And thinking that the case body needed to be concentric with the bullet base is beyond all reason.

Congratulations Paul on some first rate work. I hope you already have it written up for TFS.

John

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Paul Pollard posted this 10 January 2022

Here's an update on the case wall thickness test. I could find no evidence of a correlation in variation of the wall and bigger groups. It was pretty much the opposite. On Day 3, I cleaned before each group and shot one fouler before the group. The fouler shot was shot on a separate target. I then had 5 fouler shots for a group. The results are in the table.

Table of Groups

I have concluded this test for now. It may take a better shooter and analyst than I am.

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MP1886 posted this 20 December 2021

MP1886 posted this 22 hours ago

"Another useful test is to anneal your case neck after every loading and shooting.   I know a few match shooter that do this and it improved their groups.  First and foremost if you don't have near perfect cast bullets all efforts are useless and I do presume we're talking about cast bullet fliers since this is a cast bullet forum."

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MP1886, 

It is interesting that some match shooters do this and believe it improves their groups. However, this comes as an interesting second hand anecodote until me know more about the details. I agree with you, a test to pin this down would provide useful information and possibly lead to smaller groups.

If you haven't done this test please try and find time to run it and let us know what you find. Your results would be a good contribution to what we know.

I don't know why you think you have to have near perfect bullets to run a good test but at any rate near perfect bullets are easy to cast so that shouldn't be a problem.

Thanks for your suggestion.

John

 

John I must admit that keep some reject cast bullets that don't look too bad for just fooling around or for testing a velocity of a load while exprimenting.  On doing test with them, well there are certain defects that can really open up a group. These would be the ones inside the bullet that you cannot see.  I especially now with the state the country is in about componants I don't like to waste what I have.  Like that match shooter pointed out the main things that cause bad groups the most perfect bullets are preferred and  I would think that would hold true in cast bullets too.  Once you have your casting technique perfected you won't weigh bullets anymore  if you previously did so. BTW the way some of those rejects shoot predecent.

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