# ok , need an expert guess...

1. ### lovdasnowWell-Known Member

Messages:
953
Joined:
Nov 13, 2005
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!

2. ### BuffalobobWriters Guild

Messages:
5,085
Joined:
Jun 12, 2001
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.

3. ### MT4XForeWell-Known Member

Messages:
708
Joined:
Oct 20, 2005
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

4. ### lovdasnowWell-Known Member

Messages:
953
Joined:
Nov 13, 2005
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.

5. ### royinidahoWriters Guild

Messages:
8,853
Joined:
Jan 20, 2004
Depending on your chamber and bore it'll be either 2965 or 3010 /ubbthreads/images/graemlins/wink.gif

6. ### GuestGuest

<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.

7. ### lovdasnowWell-Known Member

Messages:
953
Joined:
Nov 13, 2005
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.

8. ### GuestGuest

<font class="small">Code:</font><hr /><pre> Cartridge : .300 Rem Ultra Mag
Bullet : .308, 220, Sierra HP MatchK 2240
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 78 71.20 2323 2636 32473 10476 97.0 1.828
-18.0 80 72.98 2379 2765 34736 10734 97.9 1.780
-16.0 82 74.76 2435 2898 37159 10968 98.6 1.733
-14.0 84 76.54 2491 3032 39755 11179 99.2 1.678
-12.0 86 78.32 2547 3168 42536 11364 99.6 1.626
-10.0 88 80.10 2602 3307 45518 11522 99.9 1.576
-08.0 89 81.88 2656 3446 48717 11652 100.0 1.528
-06.0 91 83.66 2710 3587 52151 11760 100.0 1.481
-04.0 93 85.44 2763 3728 55822 11863 100.0 1.437 ! Near Maximum !
-02.0 95 87.22 2815 3871 59726 11962 100.0 1.394 ! Near Maximum !
+00.0 97 89.00 2867 4015 63900 12058 100.0 1.353 ! Near Maximum !
+02.0 99 90.78 2918 4159 68365 12150 100.0 1.313 !DANGEROUS LOAD-DO NOT USE!
+04.0 101 92.56 2969 4306 73148 12238 100.0 1.275 !DANGEROUS LOAD-DO NOT USE!
+06.0 103 94.34 3019 4453 78275 12322 100.0 1.238 !DANGEROUS LOAD-DO NOT USE!
+08.0 105 96.12 3069 4602 83778 12402 100.0 1.203 !DANGEROUS LOAD-DO NOT USE!
+10.0 107 97.90 3119 4753 89692 12477 100.0 1.169 !DANGEROUS LOAD-DO NOT USE! </pre><hr />
<font class="small">Code:</font><hr /><pre> Cartridge : .300 Rem Ultra Mag
Bullet : .308, 220, Sierra HP MatchK 2240
Cartridge O.A.L. L6: 3.598 inch or 91.39 mm
Barrel Length : 26.0 inch or 660.4 mm
Powder : Hodgdon Retumbo

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 80 74.40 2350 2699 31851 11012 99.4 1.855
-18.0 82 76.26 2408 2831 34120 11213 99.8 1.807
-16.0 84 78.12 2464 2966 36558 11379 100.0 1.760
-14.0 86 79.98 2520 3101 39175 11514 100.0 1.706
-12.0 88 81.84 2574 3237 41988 11642 100.0 1.652
-10.0 90 83.70 2628 3375 45013 11767 100.0 1.600
-08.0 92 85.56 2681 3512 48268 11889 100.0 1.550
-06.0 94 87.42 2734 3651 51771 12008 100.0 1.502
-04.0 96 89.28 2786 3791 55516 12123 100.0 1.457 ! Near Maximum !
-02.0 98 91.14 2837 3932 59501 12235 100.0 1.413 ! Near Maximum !
+00.0 100 93.00 2888 4074 63758 12342 100.0 1.370 ! Near Maximum !
+02.0 102 94.86 2938 4217 68308 12446 100.0 1.330 !DANGEROUS LOAD-DO NOT USE!
+04.0 104 96.72 2988 4362 73176 12546 100.0 1.291 !DANGEROUS LOAD-DO NOT USE!
+06.0 106 98.58 3038 4508 78389 12641 100.0 1.254 !DANGEROUS LOAD-DO NOT USE!
+08.0 108 100.44 3087 4656 83974 12732 100.0 1.218 !DANGEROUS LOAD-DO NOT USE!
+10.0 110 102.30 3136 4806 89966 12819 100.0 1.183 !DANGEROUS LOAD-DO NOT USE!</pre><hr />

You want to look for 90% + fill capacity and 100% propellant burn, without exceeding max pressure...

9. ### lovdasnowWell-Known Member

Messages:
953
Joined:
Nov 13, 2005
thanks for your time ric, I really appreciate it, what program is that?
well, looks like I'll start shooting some more groups....dang, was ready to start the drop chart.

10. ### krakyWell-Known Member

Messages:
301
Joined:
Sep 4, 2001
I wouldn't quit on that load yet. Wait till some other guys chime in here. I have the latest version of QC which is V3.2. Mine is predicting 93 grains to be doing 65,555psi at 3130.
I do alot of work with Quick load and it can be really accurate except for two scenarios which come into play with your load. #1 quickload freaks out on long bullets and thinks they will make more pressure than they usually do. #2 quickload doesn't have any way for guessing if your gun has freebore which makes a big difference and I'll bet my hat that your gun has freebore.

You do need to chrono that load. I have done alot of work this winter with a 300 wby and have gotten great brass life out of hornady brass which is terribly soft with loads doing 3050 fps with the 200AB. I'm thinking that if you are around 3130 fps you aren't over max.
If you have a great shooter there and don't see any pressure signs I think you're doing fine.
Lets see if some guys chime in here that used that powder and load.

11. ### GuestGuest

Each rifle is different.
Your worries now are that you are doing load development in the "winter" when it is "cold". You stand the risk of shooting that in warmer weather and having pressure go through the roof. Then you have a dangerous situation.
The program isn't fool proof but it gives you more information than you can get without hooking you rifle up to stuff that makes it look like it's going into open heart surgery.

Again, each rifle is different and you need to look at your brass, primer, check your bolt lift etc. for signs of pressure.

12. ### lovdasnowWell-Known Member

Messages:
953
Joined:
Nov 13, 2005
when i shot the other day, it was in the 70's, so it's not hot, but warmer than winter.

13. ### krakyWell-Known Member

Messages:
301
Joined:
Sep 4, 2001
Well the published load by Hodgdon doing under 3000 fps has definately been "de-lawyerised". Heck there are tons of people out there safely getting 2950 out of 24" 300 win mags. There is no reason a 300 wby with 26" barrel shouldn't get 3050fps....and there is no reason you shouldn't be the next step up with the RUM up to the area of 3130-3150 fps. If people don't chime in here I'd check some other chat rooms and do a search. I think you are fine as long as you understand pressure signs. Another thing you could do is pick out 5 shells and shoot them hard and often and see if you get 5 reloads and still have tight prime pockets....if so I think your testing is done.

Messages:
301
Joined:
Sep 4, 2001