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  1. J

    Gunsmithing ? on what lapping compound for AR upper reciever

    Re: ? on what lapping compound for AR upper reciever If the scope has 60 moa of windage adjustment to one side, that's over 5 feet at 100 yards. That's almost a degree off. You should probably be able to see this much error in the barrel if you put it on a flat surface. I don't understand...
  2. J

    Range Report Kestrel, pressure, JBM

    Re: Kestrel, pressure, JBM <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bevan</div><div class="ubbcode-body">Aside from temperature changing MV change between zero conditions/shooting conditions don't change my 100m zero? MV change from temperature change is...
  3. J

    Range Report Kestrel, pressure, JBM

    Re: Kestrel, pressure, JBM So how are you correcting for zero conditions? Are you calculating the elevation and azimuth at zero conditions and reapplying it? See here for information on what I'm talking about.
  4. J

    Range Report Kestrel, pressure, JBM

    Re: Kestrel, pressure, JBM You don't say what calculator you are using to get these numbers, so it's not clear to me whether or not you are correcting for the difference from zero. Using absolute pressures should work just fine as long as you are consistent. If you use the trajectory cards...
  5. J

    Range Report Ballistic FTE G1 vs. G7

    Re: Ballistic FTE G1 vs. G7 If you're using the same number with two different drag functions, that's your problem. The drag on the bullet is proportional to G/C where G is the value of the drag function (a function of velocity or mach number) and C is the ballistic coefficient. For the...
  6. J

    Range Report Ballistic FTE G1 vs. G7

    Re: Ballistic FTE G1 vs. G7 Just out of curiosity, what was were the BCs you used for the G7 and G1 drag functions? Brad
  7. J

    Gunsmithing Who can make these for me?

    Re: Who can make these for me? You can buy them at MSC. Take a look here Knurled Head Thumb Screws They have quite a selection if you want to look here Thumb Screws and Hand Knob Screws "Brad from NM"
  8. J

    Range Report JBM Ballistics, servers are down?

    Re: JBM Ballistics, servers are down? There are some simpler methods that you could do with paper and pen (still take a long time) that you can find in McCoy's book, Modern Exterior Ballistics. The way my site does it -- numerical integration -- would take days or weeks to do by pen and paper.
  9. J

    Range Report JBM Ballistics, servers are down?

    Re: JBM Ballistics, servers are down? They are back up this morning. Sorry for the outage.
  10. J

    Range Report JBM Ballistics, servers are down?

    Re: JBM Ballistics, servers are down? Yes, they are down. Looks like my ISP is having problems. They are working on it but don't have a time of repair.
  11. J

    Gunsmithing Question for guys threading muzzle 1/2x28

    Re: Question for guys threading muzzle 1/2x28 <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JJones75</div><div class="ubbcode-body">What do you turn the muzzle down to before you start cutting threads? I have always turned it down to .501" so after creasting...
  12. J

    Range Report New Guy Begging for Ballistics help.............

    Re: New Guy Begging for Ballistics help............. <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: azimutha</div><div class="ubbcode-body">Brad, I'd be interested to hear your opinions on why or when a zero atmosphere might be needed. </div></div> That's hard...
  13. J

    Range Report New Guy Begging for Ballistics help.............

    Re: New Guy Begging for Ballistics help............. <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: azimutha</div><div class="ubbcode-body"> Re. JBM - Brad has his own reasons for leaving zeroing weather out of Trajectory: he does not one JBM "product" to overlap...
  14. J

    Range Report New Guy Begging for Ballistics help.............

    Re: New Guy Begging for Ballistics help............. <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mouse07410</div><div class="ubbcode-body">There's another potential issue: JBM Trajectory does not use zeroing weather. So try setting (a) current weather the...
  15. J

    Range Report need help with wyoming hunt and ballistics!!!!!!

    Re: need help with wyoming hunt and ballistics!!!!!! <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: airborne307th</div><div class="ubbcode-body">im not sure about the 10000 it was a guess.. i have played with the velocity setting and have it where it lines up...
  16. J

    Gunsmithing Getting a lathe delivered/ how to unload?

    Re: Getting a lathe delivered/ how to unload? I had a G4003G delivered about a year ago. 1) make sure the Grizzly knows what is required -- since they were delivering to my house, I asked for lift gate service and a pallet truck. 2) The driver got the lathe off the truck and into my...
  17. J

    Gunsmithing Question about why to use a reamer holder

    Re: Question about why to use a reamer holder <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"> imagine a boring bar with a reach close to 3" long (or longer) and able to fit into a .300" hole or smaller making interrupted...
  18. J

    Gunsmithing Question about why to use a reamer holder

    Re: Question about why to use a reamer holder Chad -- this makes complete sense to me. I probably need to change the way I do my barrels (I'm an amateur and I only work on my stuff). I do have a question though. Given your six points and the fact that you have a CNC lathe -- why not bore...
  19. J

    Range Report jbm ballistics

    Re: jbm ballistics Did you change anything on your network, like firewall settings? My site is up and running. Brad
  20. J

    Range Report Effective range 168gr sierra

    Re: Effective range 168gr sierra <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kentactic</div><div class="ubbcode-body">weird... im using JBM... wonder what im missing...let me add that im only getting 12.1 mills of UP @ 1000 yards and the card that has shown to...
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