Messing Aroound: CNC Turned Bullet - Page 4
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  1. #61
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    Quote Originally Posted by Butch Lambert View Post
    I guess my reply disappeared. I know the cores will not machine with a carbide cutting tool.
    They would not have been meant to require any machining, trace of this alloy or that could have sought max hardness impractical for most any other application.

    Then again, there's always someone with a different approach and cutter who'd prove they COULD be turned, just for the Halibut.

    I am not he. Not my turn this month.


  2. #62
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    Are they magnetic?

    Bill

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    Quote Originally Posted by 9100 View Post
    I have also wondered about this design. Is the straight taper on the base more efficient than a streamlined curve? I can think of a couple of possibilities. You could want the bullet to disconnect from the barrel at the same instant all around. Another possibility is that the abrupt separation of the boundary layer produces drag that has the same effect as fins on a projectile, keeping it flying straight. I seem to recall a Schlieren photograph showing a shock wave from the leading edge of the taper. One post on another site says the boat tail has no effect above Mach 1 and only comes into play when the bullet slows down, which seems illogical since they are used on high velocity bullets and not on low velocity ammunition.

    Bill
    I have done quite a bit of testing on this. No only including boat tail designs but also different ogives, excluding the standard tangent and secant. Mostly using parabolic shapes governed by minimum drag formulas. As soon as I figure this site out, I'll post some pictures of what I've come up with.

  4. #64
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    vzm.img_20160401_213320.jpgHere is one of my designs that I tested against a Barnes TTSX. The first action that I used to define the boat tail is the most efficient that I've found while still maintaining excellent accuracy. I've found you need to keep the base flat, or you lose consistency and accuracy.

  5. #65
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    One venue for these might be suppressed weapons, if the bullet is subsonic the only way to reach far enough for sniping would be with a high density bullet with less drag. I've never heard anyone talk about that, they suppress .50's solely to tame the dust signature, but loaded down and with a fast enough twist a truly silent sniper rifle could reach quite a ways. A .22 long is subsonic (Do they still sell those?) but they don't have much reach or power, so in the true suppressed sniper rifle a long heavy bullet retains much of it's less than powerful starting energy and if the suppressor were able to dissipate the dust it should also silence the report if loaded slower.

    But you are probably not thinking that direction. I always wanted a Royal Thai Mauser chambered for 45-70 for a quiet killer.
    If such a bullet were subsonic only in the first half of it's travels I wonder if that would still be pretty quiet?

  6. #66
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    The 50 cal target shooters are using cnc bore riders for long range competitions, might be a commercial outlet for a .510 diameter, 1 .01" wide driving band too the rear and a .500 body, 750 to 800 grain leaded brass projectiles in a J7 form. I'd buy some.

    Also a suppressor for my 45-70 Pro-Hunter is due this month, not really planning on sub sonic yet, just to reduce the ringing in my ears after the deer hunt (legal in OH now) Might see if I could get a 500g lead flat point slug under 1050fps with a bulky powder.I never shoot past 70 yards around here anyway, woodlands.

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  8. Likes JNieman, michiganbuck, 3strucking liked this post
  9. #68
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    Quote Originally Posted by FredC View Post
    I knew they had a larger diameter than the 5/8 T slot. Did not figure they were made for an existing barrel, that's why I guessed paper weights. If you count getting familiar with the machine then it was worthwhile. Still wish I had that kind of time.
    Fred, we all have the time, it's just how we choose to use it... By the time you finished reading and typing you replies you could have dropped two of your own in the parts catcher....

  10. #69
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    Yeah, about 2 minute cycle time then 30-45 seconds to face off the parting nub on the back. It takes longer to wash my grubby finger prints off and package them up than it does to make them.

    Paper Weight CNC Turned Bullet - YouTube

    Edit: I was having to many damaged parts because they were dropping inconsistent when parting off. Some were kicking up and hitting the adjacent tool holder and some were missing my 5gallon bucket parts catcher. I ended up parting to .125" and breaking it off by hand. Have not had a damaged part since.

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    Don't think I've ever seen a collet setup like that before.

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    Quote Originally Posted by wesg View Post
    Don't think I've ever seen a collet setup like that before.

    I can get an entire set of 5c collets in 32nds for the price of one 31/32 16c collet that'd I'd probably never use again!

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    Wow, wonder what the ballistic coefficient on that thing would be! with an ogive that long and the meplat so sharp, I'd say maybe 5! lol. Of course on a VLD shaped projectile you really wouldnt want those cannelures on the bearing surface but they sure look cool. Great job! Jesse

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    Quote Originally Posted by 300sniper View Post




    Real Bridgeport Table

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    Quote Originally Posted by WRL View Post
    Real Bridgeport Table
    That's actually a 1987 Sharp FIRST HMV. I know I'll catch crap for this, but it's as nice, or nicer than any Bridgeport I've seen. I love that machine.

  16. Likes CalG, WRL liked this post
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    Quote Originally Posted by WRL View Post
    Real Bridgeport Table
    You bumped a 5 year old post for that?

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    Quote Originally Posted by TeachMePlease View Post
    You bumped a 5 year old post for that?
    At least it wasn't spam...his heart was in the right place

  19. #77
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    We made a bunch for shooting F class and ELR. Most shops use a Swiss lathe to make them as a standard lathe can be a problem cutting the ogive. We used brass and then switched to copper. .338 and .308 bullets shot great but the brass was too long when the correct weight was determined. The copper solids shoot little groups but take time to make in large amounts. Those look great.


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