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Thread: A "Case dynamics" question

  1. #1
    Boolit Master
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    A "Case dynamics" question

    (Mods, Not quite sure where to put this - If this isn't the right place, please feel free to move it!)

    I saw a (to me) odd YouTube video earlier. I'll refer to it in a future post. In this video, the maker of the video is stating that neck sizing is evil, wrong, causes hair growth on the back of your hands and the inside of your eyelids, makes you mean to nice people, makes you cheat on your taxes and drive stupidly, and so on (well, not quite, but darn near all that.)

    My understanding of case dynamics (what happens with the case when you touch off a round in a bolt action rifle, specifically) is that the brass expands to obturate the chamber, preventing gas leakage past the case; As pressure drops, later, the case slightly shrinks (since there isn't 45k PSI or so pressure inside it any more, forcing it against the chamber walls) and will then extract easily. If you opened the bolt and then re-chambered the same fired case, my experience has been that that fired case will happily chamber with no issues. Maybe a smidge of bolt force needed but no hammering needed to close the bolt. Since it shrank once the pressure dropped, it's smaller than the chamber, unless pressures are insanely high?

    The guy making this video, on the other hand, claims that neck sizing causes no end of horrors - Claims that people are having to hammer the bolt closed to get neck sized rounds to seat, and later hammer the bolt open to get the action to open; Claims that people get lug galling from firing neck sized cases; and so on. Claims it hurts accuracy horribly and reduces the life of your brass. He's an "authority figure" to some but, watching his rant, I felt like I was watching Alice in Wonderland or something...

    Am I incorrect in my experience that, if you have to hammer the bolt closed on a round, it strongly implies that something is HORRIBLY wrong with said round? My guess would be that someone's running pressures around 65k PSI or something, not safe pressures like the 45k PSI I try to stay near... Severe head expansion + then just neck sizing WOULD cause that, but you're NOT going to solve the CAUSE of this problem by just full length sizing!

    And the same for having to hammer the bolt open, to me that implies SEVERELY high pressures, not implies that neck sizing is bad...

    In what, 52 years or so of reloading, I don't recall ONCE having to hammer a bolt closed OR open; Call me paranoid if you want but I stop at "the bolt is a teeny smidge sticky to open" instead of insisting on increasing the pressure to the point of the rifle screaming at me "OWWWWWW THAT HURT, YOU MEAN SO AND SO, NEXT TIME I'M GOING TO BLOW UP IN YOUR FACE!" I try to be kind to my hardware!

    Has anyone else here had experiences contrary to what I'm saying here? It makes me wonder what in the world is going on there...

  2. #2
    Boolit Master Harter66's Avatar
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    Well everything I own and shoot with the exception 3 rifle cartridges and 1 pistol cartridge are over 75 yo the babies are pushing 40 .........

    I neck only the whole 1.280 clan of pistol brass no issues .
    It takes 4-5 cycles , 3 in a slide action Rem to get fussy about fits .
    I size either to the tightest chamber for muti gun cartridges or short/neck size for single cartridge/guns .

    I've been told on the net that it's bad juju to only neck or short size and that doing so adds nothing to case life or accuracy . My 264 WM , 06' and 45 Colts carbine would like to disagree with that .
    I have a rifle that takes a lot of effort to get brass small enough to go in it and on the 3 firing it becomes a 50/50 on getting a short sized case to go back in the chamber as fired . It's tight all over except the neck and throat/lead . It head spaces at the shoulder/body jct and is short necked and long shouldered about .01 . That is a great way to split necks also with FL sizing every time .
    The Colts carbine has a .484 neck and a .49? body when check when run through the carbide dies all comes out at .478 and has a coke bottle profile when you put a bullet back in the case .024 is a lot of movement . It works the brass and it splits .

    I've found that most of the FL and SBD pushers that loath the neck sizer guys shoot new guns from last Tuesday's production , buy new brass and trow away whole lots of brass when one case splits and refuse to anneal a case . They argue for bushing dies and turned necks but against annealing and neck sizing .

    In the end I'm like "yep you're right , my 1/4 inch marked cloth tape must have slipped in the rain when I measured that MOA close in groups , I'll never do that again " and go on my way .
    In the time of darkest defeat,our victory may be nearest. Wm. McKinley.

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  3. #3
    Boolit Man
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    imho Any one that is hammering a bolt closed is no one I want to be near at the range. (adjectives about the person left out). I have neck sized for years, it extends case life. Problems "can" occur if you don't keep brass separated by rifle. If chambers are different length and you use brass from the longer chamber in the shorter it may not fit. The only reason we size cases is so that they go back in the chamber and we have bullet tension (neck sizing does that for us quite well).

    Many years ago a friend bought a Mauser someone had buba'd, the chamber was actually oval. We would mark the cases so they went back in the chamber the same way and would neck size. That rifle would shoot tiny little groups as long as you took the time to orient the cases.

    The world is full of idiots. With all the new social media they can even be "famous".

  4. #4
    Boolit Master
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    If a cartridge is fired in one rifle and the case is neck sized, it may not fit into another rifle.

  5. #5
    Boolit Master
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    But it was on the internet so it has to be true.

  6. #6
    Boolit Master
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    Even worse, YouTube.

  7. #7
    Boolit Bub
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    I have frequently found that fired cases won't fit in the chamber of the same rifle whether bolt action or semi (or machinegun) and I don't do any neck sizing. I have a friend who neck sizes and all his cases are marked with a dot on the case head so he can get them oriented the same way every time. He claims that neck sizing is great but only if you put the case back the same way it came out. I don't argue with him. He shoots tiny little groups at very long range. Others neck size less religiously or moreso and seem successful. While I don't I can't see any reason to claim its evil. Neck size if you want or don't. Many of my toys are machineguns and the primary desire is that they function. Hitting the target is a bonus. The rifles I have that shoot little groups are all full length sized because its the way I do it.....not because its the only way. To each his own and success is widespread so all can't be wrong.....


    Frank

  8. #8
    Boolit Master
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    Hi Frank,

    Machineguns usually have larger chambers than sporting guns. Cases expand much more, and usually do not contract to a diameter as small as those of sporting guns. Often, cases fired in machineguns cannot be full-length sized to function correctly in sporting chambers, let alone neck sized.

    Well made sporting bolt action rifles will usually accept cases that were fired in them. Chambers that are oblong are the exception, but they are rare these days.

    Take care, Tom

  9. #9
    Boolit Master
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    ... Oval... Chambers ... -goggles a bit- The words "That is just so WRONG!" come to mind!

  10. #10
    Boolit Master
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    And yet another reason to ignore youtube reloading/shooting/casting videos...

    I neck size for my Ruger 308 (in which I use a lot of LC brass, F/L sized first reload). In my experience I can get a few reloads just neck sizing and then a F/L sizing is needed to get the other case dimensions back in line (stiff chambering). I am not a bench rest shooter and a fair to mediocre rifleman and with my handloads the best I can get is 7/8", occasionally, at about 100, of which I am delighted when that happens. My 308 is the only rifle I reload for that I go to the "extra" processes and neck sizing is one, but I don't have any "plain old reloads" to compare...
    My Anchor is holding fast!

  11. #11
    Boolit Master

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    Quote Originally Posted by Tatume View Post
    Even worse, YouTube.
    Yup, I’m not a big fan of You Tube. There are no qualifications to post. Anyone with nothing to do can post a video. There is some good stuff but one needs to remember that being on the internet does always make it true.

  12. #12
    Boolit Master
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    Quote Originally Posted by Mr_Sheesh View Post
    ... Oval... Chambers ... -goggles a bit- The words "That is just so WRONG!" come to mind!
    Out-of-round chambers were fairly common at one time, as were chambers that were not aligned with the centerline of the barrel. Modern mass-produced barrels are almost a miracle compared to the state of the art not too many years ago.

  13. #13
    Boolit Master

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    I take anything said on YouTube. With a grain of salt. YouTube can be very useful on a variety of
    functions but I am very careful about what I information I accept as truth. I rarely log onto it for this reason. The only rifle I have ever had clambering problems with had nothing to do with sizing die used. The reason cases chambered tight was that the rifle was one of the very first Model 700’s and was camber minimum chamber specs. New cases needed to be run through a full length die and even then they chambered a little snug. After firing they still had to full length sized.
    This is the only rifle
    I have owned that was chambered this tight. James

  14. #14
    Boolit Master
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    Quote Originally Posted by lightman View Post
    Yup, I’m not a big fan of You Tube. There are no qualifications to post. Anyone with nothing to do can post a video. There is some good stuff but one needs to remember that being on the internet does always make it true.
    YouTube tutorial videos are often made by people doing something for the first time. Why someone who has zero experience thinks himself qualified to teach others is beyond me. But I see the same thing in gun magazine articles all too often.

  15. #15
    Boolit Master
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    Quote Originally Posted by TNsailorman View Post
    The only rifle I have ever had clambering problems with had nothing to do with sizing die used. The reason cases chambered tight was that the rifle was one of the very first Model 700’s and was camber minimum chamber specs.
    That is fairly unusual. Chamber reamers get smaller with repeated use, and the first chambers cut with a particular reamer are the largest. Reamers that were originally ground to cut SAAMI max chambers are discarded when chambers get down to SAAMI min.

  16. #16
    Boolit Master
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    This is the video. He's a competitive shooter, I think I'll just stay far from where he's shooting, maybe. Not expired YET and in no hurry to manage that. Been looking at loads I like, I really LIKE to stay under 45k PSI if the load gives good velocity. And some good loads do

  17. #17
    Boolit Master
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    Quote Originally Posted by Mr_Sheesh View Post
    This is the video. He's a competitive shooter, I think I'll just stay far from where he's shooting, maybe. Not expired YET and in no hurry to manage that. Been looking at loads I like, I really LIKE to stay under 45k PSI if the load gives good velocity. And some good loads do
    The guy doesn't evoke confidence in me!

  18. #18
    Boolit Master
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    Yep same. If I had a bolt gun where I couldn't open the bolt with hand strength ALONE, I'd be taking it to a gunsmith (unless I figured "OOPS I messed up BADLY" and had overcharged or had a partial powder dump then a 1+the rest of that charge) - He's talking like the people he shoots with are ALL having that kind of experience? Now THAT is a scary bunch to stay FAR away from!

  19. #19
    I have a 308 that won’t chamber the neck sized brass from the previous barrel has to be full length sized before I can neck size again been so long since I had it out and used old brass in it but I remember some tight chambering and extracting with some loads


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  20. #20
    Boolit Master am44mag's Avatar
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    Youtube is great for the sharing of ideas. Of course, not all ideas are good ones. I tend to subscribe to the good ones and ignore the bad ones.
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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check