Quickload request 7-08

bdbrown66 · Jun 1, 2021

Dr. Mike, if I may trouble you, sir...

7mm-08
Winchester case
140gr Prvi Partizan BTSP
IMR 4166
CCI 200 and WLR primers (I want to compare numbers between these 2)

Since these bullets aren't real common in the usual published load data, I have been extrapolating data from Hodgdon data for Hornady 139gr SP, and Sierra data for their 140gr SP's.

Thank you for your time, sir!

Brian

DrMike · Jun 1, 2021

Unfortunately, QL does not distinguish between primers. The default assumption is that the load will use the coolest (least brisance) primer that will work with the powder column. I would predict that you will achieve slightly higher velocity with the WLR contra the CCI200. I would not expect much more than a modest difference in velocity (perhaps 25-45 fps).

Code:

Cartridge          : 7 mm-08 Rem.
Bullet             : .284, 140, PrviPartizan PSP BT B-400
Useable Case Capaci: 48.660 grain H2O = 3.159 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : IMR 4166 Enduron *C*T

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   91    38.88   2505    1950   43792   8277     92.6    1.239
-09.0   92    39.31   2531    1992   45130   8379     93.0    1.222
-08.0   93    39.74   2558    2034   46508   8479     93.5    1.205
-07.0   94    40.18   2584    2076   47927   8578     93.9    1.188
-06.0   95    40.61   2611    2119   49389   8675     94.3    1.172
-05.0   96    41.04   2637    2162   50894   8770     94.7    1.155
-04.0   97    41.47   2663    2205   52446   8863     95.1    1.140  ! Near Maximum !
-03.0   98    41.90   2690    2249   54044   8954     95.5    1.124  ! Near Maximum !
-02.0   99    42.34   2716    2294   55692   9043     95.9    1.109  ! Near Maximum !
-01.0  100    42.77   2743    2338   57391   9129     96.2    1.094  ! Near Maximum !
+00.0  101    43.20   2769    2383   59142   9214     96.5    1.079  ! Near Maximum !
+01.0  102    43.63   2795    2429   60948   9296     96.8    1.064  !DANGEROUS LOAD-DO NOT USE!
+02.0  103    44.06   2821    2475   62810   9375     97.2    1.050  !DANGEROUS LOAD-DO NOT USE!
+03.0  104    44.50   2848    2521   64732   9452     97.4    1.036  !DANGEROUS LOAD-DO NOT USE!
+04.0  105    44.93   2874    2568   66715   9527     97.7    1.022  !DANGEROUS LOAD-DO NOT USE!
+05.0  106    45.36   2900    2615   68762   9599     98.0    1.009  !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    101    43.20   2888    2592   68535   9223     99.6    1.011  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    101    43.20   2616    2128   49933   8853     90.4    1.167

bdbrown66 · Jun 1, 2021

Dr. Mike,

Thank you so much. I'm at 42.7gr with the CCI primers, and based on this info I'm not getting into the danger zone. I'm going to load a few with the WLR's at the same specs and see how they do. It appears that I won't be in dangerous territory, but I'll watch for pressure signs.

Cheers,
Brian

DrMike · Jun 1, 2021

You should be fine. From my perspective, I'd say you're approaching your development with appropriate safety. Should be interesting to see your results.

bdbrown66 · Jun 1, 2021

Here's where I'm at right now with the CCI primers. Shot this group yesterday. It's taken a little while to nail this load down. I think mostly it's due to these bullets not being as consistent as I'm used to with the Nosler, Sierra, and Hornady bullets. As I was working up the loads, I would get occasional flyers that I couldn't explain. Maybe the WLR's will be a better option.

DrMike · Jun 1, 2021

It's worth a try to see if higher brisance yields tighter groups, though that looks more than adequate for hunting right now. I have not worked with the partizan bullets much beyond some studies in the 8mm Mauser.

SJB358 · Jun 1, 2021

I’d try seating a little deeper as well.

Mikes suggestion of a primer swap is solid as well.

bdbrown66 · Jun 1, 2021

SJB358":3pwh8iaf said:
I’d try seating a little deeper as well.

Mikes suggestion of a primer swap is solid as well.

I tried seating them at .025, .020, and .015" off the lands. They seemed to prefer .015." I guess I could go on down to .010", if the primer swap didn't improve things.

I've got 5 each loaded with CCI 200's, WLR's, and Remington 9.5's.