Seating depth work.

[ksubuck]

I am finishing load workup with my 7 rem mag using 150g LRABs. They shoot consistent 0.7 MOA at 0.050 off the lands. The COAL will not quite fit into the magazine. Today, the original load went 0.5 MOA. Then I ran 4 more groups each seated 0.010 deeper into the case. I saw 1.0 to 2.0 MOA with all of these. Is there a chance if I keep going deeper that I will find another point at which I will go sub MOA again? Or will I just be wasting components. I would love to be able to run this load through the magazine easily. Otherwise, I will remove a small amount of material from the mag and see how they feed.

 

[Wyo7200]

We can look at the estimated numbers in ql- What's your barrels length, velocity, load, case capacity?

 

[Ridgerunner665]

Load 3-5 at 3.34" OAL and see what they do.... They just might surprise you.

 

[ksubuck]

24 inch barrel. Load is 150gn LRABs over 66.0gn IMR 7828, OAL 3.425 which puts me 0.050 off lands, case capacity 84.3gn water average. I have not run it over the magneto yet, but would bet it is running 3025 give or take. That speed seems to pop up quite frequently with accurate loads in this rifle.

Ridgerunner. I have heard some of these long range rounds will have a second depth where they settle down again, often when seated fairly deep. I take it you have seen this. Will give 3.340 a run soon.

And I am getting closer to investing in this thing called Quickload

 

[Wyo7200]

24 inch barrel. Load is 150gn LRABs over 66.0gn IMR 7828, OAL 3.425 which puts me 0.050 off lands, case capacity 84.3gn water average. I have not run it over the magneto yet, but would bet it is running 3025 give or take. That speed seems to pop up quite frequently with accurate loads in this rifle.

Ridgerunner. I have heard some of these long range rounds will have a second depth where they settle down again, often when seated fairly deep. I take it you have seen this. Will give 3.340 a run soon.

And I am getting closer to investing in this thing called Quickload

24" node is 1.2282

Cartridge          : 7 mm Rem. Mag.(SAAMI)
Bullet             : .284, 150, Nosler Accubond LR 58734 G7
Useable Case Capaci: 77.737 grain H2O = 5.047 cm³
Cartridge O.A.L. L6: 3.425 inch = 87.00 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : IMR 7828 ?

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   85    59.40   2715    2456   38970  12153     95.5    1.423
-09.0   86    60.06   2746    2511   40209  12300     96.0    1.401
-08.0   87    60.72   2776    2567   41489  12442     96.4    1.380
-07.0   88    61.38   2807    2624   42802  12581     96.8    1.360
-06.0   89    62.04   2837    2681   44174  12714     97.2    1.340
-05.0   90    62.70   2868    2739   45583  12843     97.6    1.320
-04.0   91    63.36   2898    2797   47036  12966     97.9    1.301
-03.0   92    64.02   2928    2856   48539  13085     98.3    1.282
-02.0   93    64.68   2958    2915   50090  13198     98.6    1.263
-01.0   94    65.34   2989    2975   51695  13306     98.8    1.245
+00.0   95    66.00   3019    3035   53351  13408     99.1    1.227  ! Near Maximum !
+01.0   96    66.66   3049    3095   55064  13504     99.3    1.209  ! Near Maximum !
+02.0   97    67.32   3078    3157   56833  13594     99.5    1.192  ! Near Maximum !
+03.0   98    67.98   3108    3218   58655  13679     99.6    1.175  ! Near Maximum !
+04.0   99    68.64   3138    3280   60530  13757     99.7    1.158  !DANGEROUS LOAD-DO NOT USE!
+05.0  100    69.30   3168    3342   62460  13829     99.9    1.141  !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     95    66.00   3162    3330   64393  13013    100.0    1.132  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     95    66.00   2820    2649   43146  13039     93.3    1.349

With the 3.340 OAL:

Cartridge          : 7 mm Rem. Mag.(SAAMI)
Bullet             : .284, 150, Nosler Accubond LR 58734 G7
Useable Case Capaci: 76.377 grain H2O = 4.959 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : IMR 7828 ?

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   87    59.40   2742    2504   40150  12121     95.8    1.401
-09.0   88    60.06   2773    2560   41446  12264     96.3    1.381
-08.0   89    60.72   2803    2618   42784  12402     96.7    1.359
-07.0   90    61.38   2834    2675   44167  12535     97.1    1.339
-06.0   91    62.04   2865    2734   45595  12664     97.5    1.319
-05.0   92    62.70   2896    2793   47070  12787     97.9    1.300
-04.0   93    63.36   2926    2852   48596  12906     98.2    1.280
-03.0   94    64.02   2957    2912   50173  13019     98.5    1.261
-02.0   95    64.68   2988    2973   51804  13126     98.8    1.243
-01.0   96    65.34   3018    3034   53488  13228     99.0    1.225  ! Near Maximum !
+00.0   96    66.00   3048    3095   55232  13324     99.2    1.207  ! Near Maximum !
+01.0   97    66.66   3079    3157   57035  13414     99.4    1.189  ! Near Maximum !
+02.0   98    67.32   3109    3219   58901  13498     99.6    1.172  ! Near Maximum !
+03.0   99    67.98   3139    3282   60824  13576     99.7    1.155  !DANGEROUS LOAD-DO NOT USE!
+04.0  100    68.64   3169    3345   62805  13647     99.8    1.138  !DANGEROUS LOAD-DO NOT USE!
+05.0  101    69.30   3199    3409   64846  13711     99.9    1.122  !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    66.00   3190    3389   66717  12896    100.0    1.114  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     96    66.00   2850    2706   44636  13014     93.7    1.327

 

[Firebird]

I had the same problem when I was working up the ablr in my stw-I never found that mythical second sweet spot. I did end up buying a magazine extender. I got mine from Wyatt's outdoors-but I suspect other companies have them as well. Not a lot of money and looks/works great.

 

[ksubuck]

I am going to give up on finding the second sweet spot because of my last two shooting sessions with this load. I ran the 66.0g load over the chrono and came up a bit short of what I expected with an average of 2990fps. I then bumped up the charge to 66.3g and shot a 0.295 and 0.408 with it. The chrono of that load turned out to be 3025.

Now to hog a tiny amount of material out of the ABolt magazine...

A big thanks To Wyo! I like working with the OBT theories. Slicker than snot. Definately investing in QuickLoad in the near future. Honey, I am gonna spend some more money. Honest, it will save money in the long run...