Browning X-bolt 7mm mag with 26" barrel

[sask boy]

Good evening Ladies & Gentlemen was wonder if some could post a Quick load using IMR 7828ssc. & 168gr. ABLRs.
I have friend being advised that unless you have a barrel with 1-9.25 twist or faster that 168gr. ABLRs won't stabilize?
Looking forward to getting the quick load & listening to what you think about the twist question.

Blessings,
Dan

 

[Wyo7200]

Cartridge          : 7 mm Rem. Mag.(CIP) M70 Nickel
Bullet             : .284, 168, Nosler Accubond LR 58623 G7
Useable Case Capaci: 74.848 grain H2O = 4.860 cm³
Cartridge O.A.L. L6: 3.280 inch = 83.31 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 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   84    59.67   2735    2791   39675  11808     95.4    1.502
-09.0   85    60.33   2767    2855   40944  11954     95.8    1.479
-08.0   86    61.00   2798    2921   42254  12096     96.3    1.457
-07.0   87    61.66   2829    2986   43608  12234     96.7    1.435
-06.0   88    62.32   2861    3053   45008  12367     97.1    1.413
-05.0   89    62.99   2892    3120   46453  12496     97.5    1.392
-04.0   90    63.65   2923    3188   47947  12620     97.8    1.371
-03.0   91    64.31   2955    3257   49493  12740     98.1    1.351
-02.0   92    64.97   2986    3326   51091  12854     98.4    1.331
-01.0   93    65.64   3017    3396   52744  12964     98.7    1.311
+00.0   94    66.30   3049    3467   54453  13068     98.9    1.292  ! Near Maximum !
+01.0   94    66.96   3080    3538   56210  13167     99.2    1.273  ! Near Maximum !
+02.0   95    67.63   3111    3610   58054  13260     99.3    1.254  ! Near Maximum !
+03.0   96    68.29   3142    3682   59947  13348     99.5    1.236  ! Near Maximum !
+04.0   97    68.95   3173    3755   61913  13430     99.7    1.217  !DANGEROUS LOAD-DO NOT USE!
+05.0   98    69.62   3204    3829   63947  13505     99.8    1.200  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba     94    66.30   3128    3651   60241  12931     99.9    1.238  ! Near Maximum !
Data for burning rate decreased by 5% relative to nominal value:
-Ba     94    66.30   2954    3256   49076  13000     96.6    1.352

give me one sec and Ill post the miller stability calc comparison...

 

[Wyo7200]

Compared to the best indicated loads from Nosler's 160gr AccuBond data... I think it'll do just fine in the 9.25 twist. I used 9.5 (my rifles twist) to model the above QL.

Your 168gr ABLR is the bottom line. It calculates to the optimal twist rate of 10.3, rounded to 10.

 

[sask boy]

I am sorry as I did not fully explain as my friend was told nothing slower than 1-9.25 & his X-bolt is 1-9.5.
Sorry again .

Blessings,
Dan

 

[Wyo7200]

Haha, yeah for some reason I put 9.25 instead of 9.5 in the post above. Meant to say they were "calcuated with a 9.5 twist. "

I could do one at 11 twist just to see the numbers, but if the optimal twist says ten, I don't think 11 is slow enough. If accurateshooter is right with optimal twist rate calculations (my source for these equations), don't think you'll see any difference until 12-13 twist. Just numbers though, could be wrong.

 

[sask boy]

Thank you very much for information.
If I am not pushing it he would like one more quick load using H1000 all the rest is the same.

Blessings,
Dan

 

[Wyo7200]

I just changed back to the Mac OS so I can get my iPad ready for a trip... When it's done updating I can switch back to Windows if no one else has done one yet.

Just for giggles:
11 twist miller stab said 1.11
12 twist Miller stab said .9

 

[sask boy]

Again thank you!! Have a safe trip!

Blessings,
Dan

 

[jimbires]

Dan , here is a chart to what Brian Litz , from berger bullets , has to say about the twist rates on the ABLR bullets . his first post pretty much says it all . the bullets will stabalize and shoot well with a slower twist , " BUT " to get the advertised BC of the bullet , or close to that BC , it requires a faster twist . since these findings Brian has retested the berger bullets and has adjusted the recommend twist , and the BC of berger bullets . an unstable bullet , wobbling around in flight , cannot have as high of a BC as a perfectly stable bullet , but it can still shoot accurately .


there is a link to a stability calculator in his post too .


http://www.longrangehunting.com/forums/ ... ts-137554/


I found one more link that explains this , and I think you'll find interesting . Jim

http://www.bergerbullets.com/update-of- ... ance-data/

 

[jimbires]

I think I have used the same info as wyo7200 .


Cartridge : 7 mm Rem. Mag.(CIP)
Bullet : .284, 168, Nosler AccuBond LR 58623 G7
Useable Case Capaci: 71.513 grain H2O = 4.643 cm³
Cartridge O.A.L. L6: 3.290 inch = 83.57 mm
Barrel Length : 26.0 inch = 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 86 56.00 2385 2121 30336 9558 91.1 1.717
-18.0 88 57.40 2449 2237 32502 9875 92.5 1.669
-16.0 90 58.80 2514 2357 34834 10177 93.9 1.622
-14.0 92 60.20 2579 2480 37348 10461 95.1 1.576
-12.0 94 61.60 2644 2607 40059 10726 96.2 1.524
-10.0 97 63.00 2709 2738 42985 10970 97.1 1.474
-08.0 99 64.40 2775 2872 46150 11190 98.0 1.425
-06.0 101 65.80 2840 3009 49575 11386 98.7 1.378
-04.0 103 67.20 2905 3148 53289 11555 99.2 1.333 ! Near Maximum !
-02.0 105 68.60 2970 3291 57321 11696 99.6 1.289 ! Near Maximum !
+00.0 107 70.00 3035 3436 61707 11806 99.9 1.247 !DANGEROUS LOAD-DO NOT USE!
+02.0 110 71.40 3100 3584 66486 11885 100.0 1.206 !DANGEROUS LOAD-DO NOT USE!
+04.0 112 72.80 3164 3733 71703 11940 100.0 1.167 !DANGEROUS LOAD-DO NOT USE!
+06.0 114 74.20 3227 3885 77419 11988 100.0 1.128 !DANGEROUS LOAD-DO NOT USE!
+08.0 116 75.60 3291 4039 83689 12031 100.0 1.091 !DANGEROUS LOAD-DO NOT USE!
+10.0 118 77.00 3354 4196 90585 12066 100.0 1.056 !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 107 70.00 3169 3747 75594 11272 100.0 1.150 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 107 70.00 2836 3000 49789 11792 95.5 1.372

 

[sask boy]

Thank you very much for the added information, I am trying to learn as much as I can on this longrange stuff as I find it very interesting and have been asked to join a group of shooter who are starting a club.
Long distance shooting in Saskatchewan should really take off as we only have 3 hills in the whole province :lol: :shock:!!

Jim, thanks for the quick load as well, my friend is quite new to the reloading game and has a million questions :wink:.

Blessings,
Dan

 

[SJB358]

That H1000 looks like it could be super. Bill Casey uses H1000 in his 7mm Rem Mag with 160 ABs and seems to be stacking stuff up pretty neatly with it. It's magical in my 7mm Mashburn as well.

 

[DrMike]

Long distance shooting in Saskatchewan should really take off as we only have 3 hills in the whole province :lol: :shock:!!

Blessings,
Dan

Yeah, and none of the three are anywhere near Regina. :mrgreen:

 

[Wyo7200]

Sorry I couldn't hop back on last night. Haven't used the iPad in over a year and it took 3 hours to charge to 2%. Called it quits at midnight and went to sleep for four hours before an hour and half drive to the airport.

Flying southwest, they do not have assigned seats so I looked on the web for tips- #7 was don't be good looking or else surrounding seats will fill up fast. It's true, I was surrounded pretty fast.

Glad Jim helped ya out

 

[DrMike]

Flying southwest, they do not have assigned seats so I looked on the web for tips- #7 was don't be good looking or else surrounding seats will fill up fast. It's true, I was surrounded pretty fast.

Modesty becomes you. Well, that accounts for why I always have lots of room. :lol: :lol: