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Thread: A test of imbalanced bullets

  1. #1
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    A test of imbalanced bullets

    After some back-and-forth with The Evil Boolit Brothers (Goodsteel and Sgt. Mike) we devised small test to try to quantify the effect that an imperfect cast bullet would have in a high velocity cartridge. We figured that Big Bertha, my XCB target rifle, would make a suitable test bench, and I prepared the test as follows:
    20 bullets, NOE 165 gr. XCB variant, cast from Rotometals Hardball, visually inspected and weight sorted to within 0.1 grs, were selected. 10 of them were gas checked, lubed with Lars 2500+ and sized to .309, and then loaded over 45 grs. IMR4831. This load had given reasonable accuracy before, and had chronographed in the 2550 fps range, so no chronograph was used for this test.
    The other 10 bullets were prepared like this:
    Click image for larger version. 

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    A 1/16" hole was drilled slightly off center in each bullet base, about 1/4" deep, to simulate an internal void in the bullet.
    They were then prepped and loaded as described above, and fed to Bertha:
    Click image for larger version. 

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    I'm sure I'm not the first person to run this test, but I wanted to show decisively the effect poor bullet casting has on target results. YMMV.

  2. #2
    Boolit Master
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    Simple and to the point, excellent demonstration!
    One way to avoid such imperfections in cast boolits is to buy them from The Bullshop.

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    So, how come your "good" bullets didn't all go into the same hole?

    Gear

  4. #4
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    My boolits all go into the same hole as long as the hole is big enough.

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    At what distance were these shot ?

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    The Evil Boolit Brothers. That's got a nice ring to it.

  7. #7
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    There is a YouTube video of .22 rf bullets with their noses all hacked up, for the same purpose. Some were predictably wild, others were surpisingly accurate.
    Warning: I know Judo. If you force me to prove it I'll shoot you.

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    Quote Originally Posted by geargnasher View Post
    So, how come your "good" bullets didn't all go into the same hole?

    Gear
    THAT, Gear, would have meant that I had found the Holy Grail and was lounging on a Caribbean beach with hula girls serving me drinks with little umbrellas!

  9. #9
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    Quote Originally Posted by FrankG View Post
    At what distance were these shot ?
    All shot at 100 yards Frank. Sorry for not including that.

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    this is why i swage all my bullets for all my guns.

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    That 45 gr 4831 load is the one I use in my 308 sept I use the h/sc version and .2gr more

  12. #12
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    I am surprised they are still on paper at that distance or even cutting a clean hole being so out of balance .

  13. #13
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    Quote Originally Posted by FrankG View Post
    I am surprised they are still on paper at that distance or even cutting a clean hole being so out of balance .
    I thought the same before I shot them. (See Runfiverun's tag line).

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    Quote Originally Posted by sgt.mike View Post



    kinda like this Gear .749" - bullet dia of .308 equals .442" five shots 100 yards with a issue in 1943 original barrel 1903a3 . I know it not exactly one hole but I'm working on it.
    Evil boolit brother #2 casted those 165 XCB boolits and evil boolit brother #1 fired them LOL

    I'd get further along if Evil boolit brother number one would cast better boolits durn it...LMAO
    OH, I thought one had to have a $1,500+ custom rifle with a superuberpremium5rrifledhandlappedreversetaperleft hand1-in-18twistheavyvarminttargetcrownedmatchchambered wondergun on a 23 -lb F-class chassis and a 6-oz. trigger to get under half an inch with cast bullets? I know what you did, you put waxed paper over the target to catch the lube spatter and powder burns, didn'tcha?!

    Good shooting, Mike. It's a good feeling when you get an old warhorse to clump them all up like that, isn't it?

    Gear

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    OK, I was changing the lightbulb in the bathroom this morning, slipped off the edge of the tub, and hit my head on the toilet tank lid. When I awoke, I had this thought: (not really)!

    Cast bullet cores pretty close to final shape, use a swage-friendly alloy like 2-3" antimony and less than 1% tin. Make it a single-lube-groove design like 45 2.1's .30 Silhouette design. Swage them using a swage press and matching form die. Trapped air would bleed out around the ejector pin at the nose, I think. I know, all been done before....BUT.....here's my epiphany: Have a three-piece tool steel negative of the lube groove that are placed into the groove prior to swaging, then popped out afterward (could put little divots on the outer edge of the ends of the three pieces to help dig them out with a pick). Swaged, low antimony bullets have proven themselves to be better than cast, but keeping the lube grooves open during the process has been a challenge. The three-piece ring might just solve that, and I think it would be practical to use, though difficult to machine.

    The bullets could be air cooled and would be 8-10 bhn right after casting, then could be oven heat-treated after swaging to achieve 20-24 bhn hardness.

    See what EBC#1 thinks about that. He is rumored to have some precision machinery at his disposal, too.....

    Gear

  16. #16
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    Quote Originally Posted by JSnover View Post
    There is a YouTube video of .22 rf bullets with their noses all hacked up, for the same purpose. Some were predictably wild, others were surpisingly accurate.
    Saw that one too. Was surprised that so many hit the target
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  17. #17
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    Liquid is not compressible so filling the lube grooves with lube before swaging should keep them unchanged after swaging.

  18. #18
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    Quote Originally Posted by garandsrus View Post
    Liquid is not compressible so filling the lube grooves with lube before swaging should keep them unchanged after swaging.
    Correct and was covered in the swaging section quite a few times, but I very much thank you for posting it here.

    I emailed a couple companies to make me some swage dies to swage my 30 XCB after casting/lubing, but no replies yet.


    BjornB, thank you for all of your time and effort here and if there is anything I can do for you to help please let me know.

  19. #19
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    Outstanding test, thanks for the work and the post. I'm kinda surprised the bad bullets grouped as good as they did but it sure does prove the point, perfect bases with perfectly installed checks.

    There was another such test (Harris maybe?) I think in the NRA cast bullet book. Very similar results.

    Rick
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  20. #20
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    Quote Originally Posted by geargnasher View Post
    OK, I was changing the lightbulb in the bathroom this morning, slipped off the edge of the tub, and hit my head on the toilet tank lid. When I awoke, I had this thought: (not really)!

    Cast bullet cores pretty close to final shape, use a swage-friendly alloy like 2-3" antimony and less than 1% tin. Make it a single-lube-groove design like 45 2.1's .30 Silhouette design. Swage them using a swage press and matching form die. Trapped air would bleed out around the ejector pin at the nose, I think. I know, all been done before....BUT.....here's my epiphany: Have a three-piece tool steel negative of the lube groove that are placed into the groove prior to swaging, then popped out afterward (could put little divots on the outer edge of the ends of the three pieces to help dig them out with a pick). Swaged, low antimony bullets have proven themselves to be better than cast, but keeping the lube grooves open during the process has been a challenge. The three-piece ring might just solve that, and I think it would be practical to use, though difficult to machine.

    The bullets could be air cooled and would be 8-10 bhn right after casting, then could be oven heat-treated after swaging to achieve 20-24 bhn hardness.

    See what EBC#1 thinks about that. He is rumored to have some precision machinery at his disposal, too.....

    Gear
    Gear,

    For a couple of years I have been doing something similar.

    Cast conventional .357 bullets either 148 grain wad cutters ( 3 lube grooves ) or 150 grain ( one lube groove ) with conventional lube grooves. Lube them in a Lyman 4500. Then with BT Snipers dies, swage them into hollow point form factor. The lube grooves cannot be swaged when filled with lube. ( Lyman 50/50 lube will not compress. ) They shoot great and reduce average group size by about 20%.
    First reload: .22 Hornet. 1956.
    More at: http://reloadingtips.com/

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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