280 AI or .270

Nosler chambering of their 280AI has not been widely distributed, what I have read said only they standardized the chambering nothing about how. It has been widely known if a standard 280Rem chamber was cut to P.O. Ackley's design that it usually was .004" longer if you used a standard 280Rem gauge, if you used the no go gauge it may close fully or not depending on the length of the parent chamber that was cut. It would seem if that is indeed true then it would be O.K. to use a standard 280Rem cases to fire form in the Nosler chamber. What is new the revelation the Nosler chamber is shorter and has a crush fit, I suppose Nosler sold more ammunition and cases by not advertising this to the shooting public. What would confirm this if a standard go 280Rem chamber gauge were used in the Nosler AI cut chamber it would not allow closure on the gauge. That would answer this question once and for all.. William
 
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I'm sorry, but,......

Can't we put this one to bed? Let's end this one and let whoever is waiting to start over with a new thread including pictures and how it all turned out. I can't bear to go back to the beginning and read through the whole thing all over again to even begin to have any confidence in making an appropriate of meaningful comment. OK, I'll shut up now.......:confused:
 
The debate was...can my 280 Ackely safely reach 3,100 fps with 150 grain Accubond LR bullets.


The answer is yes...

This isn't just a QL prediction...its a dialed in and matched up rundown...that exactly matches my results today....things tweaked to make it match are case capacity (mine is 73.9) and burn rate...changed the Ba value of MRP to .4, and everything matches every round I fired today...with 2 different bullets, the 150 ABLR and the 160 AB....the numbers, the visual indicators, and the known facts about the 280 Ackley all match here.

Code: 
Cartridge          : .280 Ack Imp
Bullet             : .284, 150, Nosler Accubond LR 58734 G7
Useable Case Capaci: 65.494 grain H2O = 4.252 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Norma MRP ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.793% 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

-07.9   92    58.00   2926    2852   51397  11872     99.8    1.246
-07.1   93    58.50   2951    2900   52835  11930     99.9    1.231
-06.3   94    59.00   2975    2948   54313  11983    100.0    1.215
-05.6   94    59.50   3000    2997   55832  12032    100.0    1.200  ! Near Maximum !
-04.8   95    60.00   3024    3046   57393  12077    100.0    1.185  ! Near Maximum !
-04.0   96    60.50   3048    3095   58998  12120    100.0    1.171  ! Near Maximum !
-03.2   97    61.00   3072    3144   60648  12161    100.0    1.156  ! Near Maximum !
-02.4   98    61.50   3097    3194   62345  12202    100.0    1.142  ! Near Maximum !
-01.6   98    62.00   3120    3243   64090  12243    100.0    1.128  ! Near Maximum !
-00.8   99    62.50   3144    3293   65885  12283    100.0    1.114  !DANGEROUS LOAD-DO NOT USE!
+00.0  100    63.00   3168    3343   67731  12322    100.0    1.101  !DANGEROUS LOAD-DO NOT USE!
+00.8  101    63.50   3192    3393   69631  12360    100.0    1.087  !DANGEROUS LOAD-DO NOT USE!
+01.6  102    64.00   3215    3444   71586  12398    100.0    1.074  !DANGEROUS LOAD-DO NOT USE!
+02.4  102    64.50   3239    3494   73599  12436    100.0    1.061  !DANGEROUS LOAD-DO NOT USE!
+03.2  103    65.00   3262    3545   75670  12472    100.0    1.048  !DANGEROUS LOAD-DO NOT USE!
+04.0  104    65.50   3286    3596   77803  12508    100.0    1.036  !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    100    63.00   3283    3590   82374  11864    100.0    1.018  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    100    63.00   2992    2981   53446  12736     98.6    1.213



Code: 
 Cartridge          : .280 Ack Imp
Bullet             : .284, 160, Nosler AccuBond 54932
Useable Case Capaci: 64.520 grain H2O = 4.189 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Norma MRP ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.833% 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

-08.3   89    55.00   2766    2718   47503  11474     99.7    1.329
-07.5   89    55.50   2790    2765   48847  11539     99.8    1.312
-06.7   90    56.00   2814    2814   50228  11601     99.9    1.296
-05.8   91    56.50   2838    2862   51647  11658    100.0    1.279
-05.0   92    57.00   2862    2910   53106  11711    100.0    1.263
-04.2   93    57.50   2886    2959   54605  11759    100.0    1.247
-03.3   93    58.00   2910    3008   56146  11806    100.0    1.231  ! Near Maximum !
-02.5   94    58.50   2933    3057   57730  11851    100.0    1.216  ! Near Maximum !
-01.7   95    59.00   2957    3107   59359  11897    100.0    1.201  ! Near Maximum !
-00.8   96    59.50   2980    3156   61033  11941    100.0    1.186  ! Near Maximum !
+00.0   97    60.00   3004    3206   62755  11985    100.0    1.171  ! Near Maximum !
+00.8   97    60.50   3027    3255   64526  12029    100.0    1.157  !DANGEROUS LOAD-DO NOT USE!
+01.7   98    61.00   3050    3306   66347  12072    100.0    1.143  !DANGEROUS LOAD-DO NOT USE!
+02.5   99    61.50   3073    3356   68220  12114    100.0    1.129  !DANGEROUS LOAD-DO NOT USE!
+03.3  100    62.00   3096    3406   70149  12155    100.0    1.115  !DANGEROUS LOAD-DO NOT USE!
+04.2  101    62.50   3119    3457   72133  12196    100.0    1.101  !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     97    60.00   3115    3446   76220  11542    100.0    1.083  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     97    60.00   2835    2854   49606  12353     98.4    1.291
 
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What I learned today...

Based on what I've seen today...the 280 Ackley doesn't show pressure until above 67,000 psi...that has always been said of Ackley rounds, and my shooting today tells me it is true.

I went to 63.5 grains of MRP under the 150 ABLR today (almost 3,200 fps)...only had slight ejector marks, bolt lift was fine, primers looked fine even...at almost 70,000 psi.

I decided 62 grains would be the MAX I would work from for my OCW workup...the other debate here was will 3,100 fps be accurate...we shall see, maybe tomorrow.
 
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280 ai

congrats on your new nosler rifle, best rifle for the price, wins awards, I have five, two customs, one trophy grade, and two patriots 26 nosler and 280AI tack drivers.
 
Ballistics Don't Matter

PRACTICE!

Point being you can get a box of .270 Winchester rounds anywhere in North America.

.280 Whatever....

OK, go to the best provisioned gun shop in Salt Lake City, Albuquerque, Boise, Anchorage, or Vancouver BC and this is what you will get.

What Caliber?

.270 Winchester they have, though .30-06 probably will do even in Africa.
 
Congrats on the new rifle. I personally stick with the more popular calibers. I avoided the short magnums but have almost purchased a number of times. Still feel they will disappear.
 
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