300 Weatherby QL Request and Node inquiry

[Dr. Vette]

I've had Dad's 300 Wby Mark V out and shot it, so I have data to start with.

Weatherby cases, capacity 103.9gr water
IMR 7828SSC powder
Fed 215M primers
Barnes 200 LRX bullet
3.665 COAL though I have them at 3.000 base to ogive when loading them.
Mark V, 26 inch barrel plus muzzle brake (Accubrake)

Based on the range session I suspect that a calculated node is around 81.5gr of powder. I was going to reshoot 81.0/81.5/82.0 to see if the node stayed in the same place now that the brass is once fired. However, if any of you who have QL could see if this is close and where the node theoretically exists that would be helpful.

Patrick

 

[DrMike]

Cartridge : .300 Weath. Mag.
Bullet : .308, 200, Barnes 'LRX' BT 30880
Useable Case Capaci: 89.823 grain H2O = 5.832 cm³
Cartridge O.A.L. L6: 3.665 inch = 93.09 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : IMR 7828 SSC

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   77    65.60   2515    2810   34876  10640     94.4    1.618
-18.0   79    67.24   2577    2949   37221  10941     95.5    1.578
-16.0   81    68.88   2638    3091   39727  11225     96.4    1.539
-14.0   83    70.52   2700    3237   42408  11493     97.3    1.501
-12.0   85    72.16   2761    3385   45277  11741     98.0    1.459
-10.0   87    73.80   2822    3537   48349  11969     98.6    1.415
-08.0   89    75.44   2883    3691   51639  12175     99.1    1.372
-06.0   91    77.08   2943    3847   55164  12358     99.5    1.331  ! Near Maximum !
-04.0   93    78.72   3003    4006   58952  12517     99.8    1.292  ! Near Maximum !
-02.0   94    80.36   3063    4166   62994  12650    100.0    1.253  ! Near Maximum !
+00.0   96    82.00   3122    4329   67297  12758    100.0    1.216  !DANGEROUS LOAD-DO NOT USE!
+02.0   98    83.64   3181    4493   71905  12853    100.0    1.181  !DANGEROUS LOAD-DO NOT USE!
+04.0  100    85.28   3239    4658   76846  12944    100.0    1.147  !DANGEROUS LOAD-DO NOT USE!
+06.0  102    86.92   3296    4825   82149  13031    100.0    1.114  !DANGEROUS LOAD-DO NOT USE!
+08.0  104    88.56   3354    4994   87847  13112    100.0    1.082  !DANGEROUS LOAD-DO NOT USE!
+10.0  106    90.20   3411    5166   93980  13189    100.0    1.051  !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 96 82.00 3238 4655 80754 12250 100.0 1.130 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 96 82.00 2948 3861 54343 12963 97.3 1.332

 

[Dr. Vette]

Mike,

Thanks for the info.
A couple of comments/questions if I may.

I would assume you adjusted this for Weatherby freebore as you often do. What I notice is that the charge grains shown here as maximum are less than what Nosler, for example lists as max (83.0). Any idea why?

Per this chart http://the-long-family.com/OBT%20Table.pdf the OBT for a 26 in barrel is 1.19 and 1.32 for nodes 4 and 5, which would be close to 83gr on your chart. Would you agree with that?

Thanks for any insight you may have.

 

[Dr. Vette]

Anyone have any additional thoughts?

If not, I'm going to go ahead with my original plans to reshoot 81.0/81.5/82.0 the groups were smallest, ES/SD was smallest and they all printed in the same area if you subscribe to the OCW theory. I'm not sure why this differs from the calculations, but...

 

[Dwh7271]

Dr V,
I agree with your conclusions re: load and nodes.
The main variable you have is what the burn rate of your particular lot of powder is. The only way I know to ascertain that is loads across the chrono. The average of those should give a number that gives us a fairly good read on what you actually have.
OCW, on the other hand, is not concerned as much with picking a particular speed to target as determining at what point your charge is "optimum" for your particular rifle as you noted in your post.
If you get some chrono readings we can tune in a bit.
On your other question. In my opinion (and only that), the loads shown in the manuals are based upon their particular lot of powder, the pressures obtained with that lot in their barrel used on the tests and fairly optimum conditions. Although in our litigious society, I can't imagine any company publishing potentially over max loads in their manual. Your chamber, lot of powder, etc will, as you know, be potentially different or even very different than the one used in their tests.

 

[SJB358]

I'm running 83 grains of IMR7828SSC in my sons 300 Wby. CCI250's and Norma cases. I am getting around 3050 with 200 PTs and phenomenal accuracy.

 

[Alaska]

180 Nosler Part
85.0 of IMR 7828
CCI 250 primers
Hornady Brass


Very accurate load
The Original Weatherby Vel.

 

[FOTIS]

300 Bee 180 AB at 3250 fps 82 gr 7828

 

[efw]

This is close to one of my wintertime sanity projects; the 208 gr AMax in my Vangard. Thinking something slower than the 7828SSC I used on 155s; maybe RL-25 or -26? H-1000? Retumbo?

Anybody have an idea of the best place to start?

 

[SJB358]

I think 7828 or Retumbo would work great with the 208's Eric

 

[kraky1]

I might be doing it wrong but I go to the range w/what I think will be a strong (not Max) load for my gun.
I bring home the chronod results and adjust quickload to what actually happened. I set temp for the range condition. If the gun is known to have freebore I adjust case capacity towards actual results. If it doesnt I adjust quickloads burn rate.
At that point in time I think its when I want to look at how close I am to nodes and which way I can go to get there.
There's just too many variables to have quickload make a call before I get to the range. (Cases, chambers, freebore, powder lots).
The exception to all this is if I have a history of using that powder in that gun w/other wt bullets so sometimes I might use what happened in the past w/a different bullet as a guide for the first time out.

 

[Dwh7271]

I might be doing it wrong but I go to the range w/what I think will be a strong (not Max) load for my gun.
I bring home the chronod results and adjust quickload to what actually happened. I set temp for the range condition. If the gun is known to have freebore I adjust case capacity towards actual results. If it doesnt I adjust quickloads burn rate.
At that point in time I think its when I want to look at how close I am to nodes and which way I can go to get there.
There's just too many variables to have quickload make a call before I get to the range. (Cases, chambers, freebore, powder lots).
The exception to all this is if I have a history of using that powder in that gun w/other wt bullets so sometimes I might use what happened in the past w/a different bullet as a guide for the first time out.

Well said.