Best NBT COAL

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  • Best NBT COAL

    I've been loading my Nosler Balistic Tip rounds to the published COAL from the Alexander Arms Reloading site (2.245). I recently went to the Forum's data from the 'Old Site' and noticed that the NBT has a wide range of COAL stettings - from 2.230 to over 2.260. With all the forums experianced shooters, there has probably been a narrower range that produces the most accurate COAL. What is my best bet for getting into the 'most accurate' range for this bullet?
    Does it look like the 123 AMAX will be as varible as the NBT?
  • sneaky one
    Chieftain
    • Mar 2011
    • 3077

    #2
    My gun shoots them like a dream at 2.250. Get a hornady oal meas. tool so you know where the bullet contacts rifling in YOUR gun. Then back off and work up Seems like most of us have a decent-Normal chamber-. For the 100 nos. I have an oal of 2.3015,, and for the 120 nos. an oal of 2.2705. I use a pacific tool and gage comparator, to find the true contact area oal. that will add to these numbers. With my gage the 100 nos. reads 2.7120. It looks cheezy, like a giant nut with no threads but full of holes. The unit is dead nuts on tho, I trust it as do many others, and it's reasonably priced,, a must have unit.

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    • #3
      That is something I haven't read about yet. Thanks, I think? I'll research the use of the oal meas tool and see if it helps me put the pieces of the reloading puzzle together a little better. I shoot and reload with the basics, but I sure don't understand all of the components that can make it all work better. Tell me this is this a set of tools I will pretty much use on this one gun (is it caliber specific?), one time, and I'll pretty much be able to determine how far to set the oglive from the lands to get the best setting for this gun.

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      • rasp65
        Warrior
        • Mar 2011
        • 660

        #4
        Sleel89
        I outlined an inexpensive method to measure COAL here: http://www.65grendel.com/forum/showt...jump-amp-crimp It is important to know the COAL of your rifle because as you shoot them the throat erodes and the COAL changes. One of the main causes of high pressure rounds in the Grendel has proven to be bullets jammed into the rifling.

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        • #5
          Originally posted by rasp65 View Post
          Sleel89
          I outlined an inexpensive method to measure COAL here: http://www.65grendel.com/forum/showt...jump-amp-crimp It is important to know the COAL of your rifle because as you shoot them the throat erodes and the COAL changes. One of the main causes of high pressure rounds in the Grendel has proven to be bullets jammed into the rifling.
          +1 To what rasp65 says.
          Otherwise it's like fishing without a depth finder.

          Hoot

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          • #6
            rasp65,
            Funny that you posted that link from the old Forum. I had no idea there was any way to pull up the 'old' info on your self made gauge. While I was reloading my AMAX, NBT's and NP's this week I actually attempted to make your gauge from memory, but did a crappy job on the cut, so when I chambered it - it did jam into lands and I felt I could not trust my 'first attempt' craftsmanship and I abandonded the idea. Thanks for the flash back, I'll try it again using your reference link. It is important to learn how to use the tools sneaky one refered to, but until I have that under my belt the rasp65 method appears to be a quick and easy substitute.

            Steel89

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            • #7
              I don't have pictures, but most firearms enthusiasts took metal shop. Make your slit neck case. Drill the flash hole out to 7/64. Tap it with a 6-32 tap. Go to the local hardware store and buy the longest 6-32 screw they have, like 3, 3 1/2, 4, whatever inches. Screw it in the threaded flash hole up until the base of the bullet rests on it with the bullet a little too far in. Holding it by the end of the screw, shove it into the chamber until it can go no further. Spin the screw in, advancing the bullet until you feel the resistance of the lands. Pull the case out. If the bullet stays in the chamber, push it out with a cleaning rod and slide it back into the case. The screw will still mark the depth. Now measure the COL. There are many ways to skin a cat. You just gotta think about it.

              Hoot

              EDIT: 8-32 or even 10-32 will probably work as well. The bigger the better.
              Last edited by Guest; 05-22-2011, 06:37 PM.

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              • #8
                Amazing the genius inspired by trying to put more than one round through one hole.

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                • #9
                  Back in a half hour. Converted images. Uploaded images. Here you go:

                  Drill 5/32


                  Tap 10-32


                  Threads look like this


                  Check Screw fit
                  omitted

                  Final assembly, note set nut


                  I had 5 images, but am only allowed 4.

                  Hoot

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                  • #10
                    Just finished one using a dremmel to cut the sides and tapped a 10/24 into an old piece of Wolf brass.
                    Thanks

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                    • sneaky one
                      Chieftain
                      • Mar 2011
                      • 3077

                      #11
                      2 messages in one. Steel I must confess I built an even cheaper version than Hoot did, zero coinage lost- a tube and a 1/8" diam. rod and a small bolt or 2, stuff from my recycle metal bin, but too ugly to post but works great. HOOT ! That looks like my workbench, and my drill, and my bullet puller, hey! did you sneak into my garage?? Hee-Hee !!!!!!!!!!!!!!!!!!!

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                      • #12
                        Alright, so I've marked my psudo round with the lands by using the 'gauge' - lets say 2.277COAL on a 120 NBT, what would be the best setting for my COAL on the rounds I load? Is there an optimum 'jump' that is best for the Grendel?

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                        • #13
                          There is no simple answer unfortunately. Other variables you can control as well will interact with one another. In the case of my chamber and where the 120 NBT hit the lands on it at 2.271, I dropped back to 2.25 with the intention of working back up to the lands while adjusting the charge. I was so satisfied with the results from 2.25 I haven't gotten back to it yet. I'm working on another caliber that is harder to get sweet than the Grendel. Y'know how it goes. The poorly behaving kid gets most of the attention.

                          Hoot
                          Last edited by Guest; 05-23-2011, 12:17 AM.

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                          • #14
                            To think that all those years of hunting I would buy stock ammo, sight in my rifle and hunt. That was it. I know now that I was missing the real fun of it all!

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                            • rasp65
                              Warrior
                              • Mar 2011
                              • 660

                              #15
                              Originally posted by steel89 View Post
                              rasp65,
                              Funny that you posted that link from the old Forum. I had no idea there was any way to pull up the 'old' info on your self made gauge. While I was reloading my AMAX, NBT's and NP's this week I actually attempted to make your gauge from memory, but did a crappy job on the cut, so when I chambered it - it did jam into lands and I felt I could not trust my 'first attempt' craftsmanship and I abandonded the idea. Thanks for the flash back, I'll try it again using your reference link. It is important to learn how to use the tools sneaky one refered to, but until I have that under my belt the rasp65 method appears to be a quick and easy substitute.

                              Steel89
                              Steel89
                              Actually it is from the current forum. I never posted any pictures on the old forum about the COAL gauge. But I have the url saved so I can lead members, who are interested in making this important measurement, to the instructions.

                              Hoot
                              Now I am going to have to make the "Hoot Modification" to the "Rasp Device". I am thinking about using threaded rod. So that would be that would be the "Rasp improvement of the Hoot modification to the Rasp Device". If you want you can patent it. Have you tried IMR 4007 SSC in your 25 WSSM?
                              Last edited by rasp65; 05-23-2011, 12:06 PM. Reason: More info

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