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Reloading Techniques For Reloading


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ok , need an expert guess...

 
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  #1  
Old 03-22-2007, 10:48 PM
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ok , need an expert guess...

ok, don't have a chrono yet, (planning on a CED Millenium, with IR screens) anyway on to the guessing.

finally found a load for my rem 700 cdl, in 300RUM.

93gr h-1000, and 200gr accubonds(can't get the smk's to shoot at all)

so please guess, as I'm curious about what the estimate would be for velocity out of this thing.

factory rem cdl, 26" tube, and like i said, 93gr H-1000, and 200gr accubond. how fast?

thanks for the guesses guys!
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Old 03-23-2007, 05:36 AM
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Re: ok , need an expert guess...

Get some drops at 300 yards, 500 yards, 700 yards and 1K+. Enter all of the environmental conditions into a ballistics computer. Enter the factory BC into the computer and then began running the program with 50 fps velocity increments of your best estimate.

When you find a combination that comes close to hitting your 500 yard drops as well as the 1K+, you then tweak the BC a little lower (usually) and the velocity lower or higher as needed. When you find a velocity and BC combination that passes exactly through ALL of your measured data then you save that for the future. And when you encounter different environmental conditions you use your velocity and BC just as if you had measured it (in fact you have measured it).

To do the process accurately you MUST have at least three data points. If you only use your 100 yard zero and a 1K+ drop you can get a infinite number of incorrect answers. There is only one true answer and you can find it with three points. I prefer four or five points being as sometimes the center of my groups are not shot in as well as they should be due to my less than artful skill with a rifle. What you are doing with the process outlined is iteratively solving by approximation an equation with two unknowns. The reason I say two unknowns is that the BC of a bullet will seldom be exactly what the manufacturer says. Small changes in the BC value change the middle part of the trajectory curve so just using velocity changes will not get you a perfect match.

The process above is what I use all of the time and before there were computers I used graph paper. I do not have a chronograph and have no need for one. Of course, I have reviewed thousands and thousands of pages of supercomputer output data and get some enjoyment from spending my day looking at numbers and graphs and my method comes very easy for me.
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Old 03-23-2007, 08:20 AM
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Re: ok , need an expert guess...

Well, according to Hogdon's On-line Reloading Data Center the max load for a 300 RUM with 200AB's is 92.5 H-1000 and their velocity for that load is 2975. So......your guess is as good as mine.
Good luck,
Jim
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Old 03-23-2007, 08:31 AM
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Re: ok , need an expert guess...

thanks for the info guys.

BB, thanks for your info, I will do that. I have exbal, so I'll start playing with it. that was a easy to understand write up, now i need to load up some more rounds and head out.

mt4, thanks for running those #'s, didn't know you could do that.

i'll let you know what i find out.
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Old 03-23-2007, 09:20 AM
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Re: ok , need an expert guess...

Depending on your chamber and bore it'll be either 2965 or 3010 [img]/ubbthreads/images/graemlins/wink.gif[/img]
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  #6  
Old 03-23-2007, 04:52 PM
 
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Re: ok , need an expert guess...

<font class="small">Code:</font><hr /><pre> Cartridge : .300 Rem Ultra Mag
Bullet : .308, 200, Nosler AccuBond 54618
Cartridge O.A.L. L6: 3.598 inch or 91.39 mm
Barrel Length : 26.0 inch or 660.4 mm
Powder : Hodgdon H1000

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 82 74.40 2470 2708 34610 10630 96.7 1.711
-18.0 84 76.26 2531 2846 37140 10890 97.6 1.664
-16.0 86 78.12 2593 2986 39861 11124 98.4 1.608
-14.0 88 79.98 2654 3129 42788 11332 99.1 1.556
-12.0 90 81.84 2715 3274 45944 11511 99.5 1.506
-10.0 92 83.70 2775 3421 49344 11660 99.9 1.458
-08.0 95 85.56 2835 3569 53013 11778 100.0 1.411
-06.0 97 87.42 2894 3719 56977 11870 100.0 1.366 ! Near Maximum !
-04.0 99 89.28 2952 3870 61261 11956 100.0 1.323 ! Near Maximum !
-02.0 101 91.14 3009 4022 65876 12038 100.0 1.282 !DANGEROUS LOAD-DO NOT USE!
+00.0 103 93.00 3066 4175 70829 12116 100.0 1.242 !DANGEROUS LOAD-DO NOT USE!
+02.0 105 94.86 3122 4330 76172 12189 100.0 1.204 !DANGEROUS LOAD-DO NOT USE!
+04.0 107 96.72 3178 4486 81941 12257 100.0 1.167 !DANGEROUS LOAD-DO NOT USE!
+06.0 109 98.58 3234 4644 88181 12321 100.0 1.131 !DANGEROUS LOAD-DO NOT USE!
+08.0 111 100.44 3289 4804 94940 12378 100.0 1.097 !DANGEROUS LOAD-DO NOT USE!
+10.0 113 102.30 3344 4967 102277 12431 100.0 1.064 !DANGEROUS LOAD-DO NOT USE!

Results caused by 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 103 93.00 3167 4456 85573 11691 100.0 1.153 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 103 93.00 2910 3761 56677 12631 99.4 1.362 ! Near Maximum ! </pre><hr />


You are over your max pressure. Max pressure is 64997. This could be why the SMK's didn't shoot as well...

Take it down to 89.3 grns.

start there...play with seating depth.
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  #7  
Old 03-23-2007, 05:16 PM
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Re: ok , need an expert guess...

thanks for all the info, ok, apparantly I might be loading a little hot. I am wondering why there are no extractor marks, no sticky bolt lift at all, primers are fine, etc, etc, no signs of excess pressure...

I worked up to that load and it ended up being the most accurate, so I wanted to use it, but maybe I shouldn't...???

I have shot the smk's over lots of differant powder charges(h-1000 and retumbo) all a lot less than this charge, and came up with less than desirable results. I would rather shoot the 220gr smk's, but no luck yet. (the only halfway decent loads I've gotten with the 220's is with retumbo, 83, 85, and 87gr loads all showed some promise.

I guess maybe I should start looking for another load, it kind of sounds like. is everyone agreeing that this one is to hot?

thanks again for the info!!! I will add, that I am somewhat new to the reloading game, but I have been able to find some great loads for my 223, and 243, but this 300 is a little elusive as of yet.

any more advice is appreciated!
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