Is it Normal???

[colt45]

Load info;
.280 rem
winchester brass
140 gr AB
57 gr RL19


I went to the range today and shot my .280 I just bought a new can of powder so I loaded 5 rounds to test. I took them and previosly loaded rounds. the powder has different lot numbers.

My first group with the previosly loaded, tried and tested rounds was less than an inch, 2 inches high at 100 yds. this is where this rifle is sighted in.

Next was the 5 test rounds out of the new lot of powder. all five was less than 3/4 of an inch, but the group is 4 inches low from the first group.

group one averaged 2860 fps, group two from the new lot averaged 2880 fps

shot a third group with old lot and had the same results of the first group

I have never had this big of a varible when going to a new lot of powder, so my question is;

Is this have I been lucky in the past and this is normal or is this an extreme result?

sorry no pics left the target at the range

thanks for any input

 

[CZ]

That¨s the way it is.-New lot, all over again most of the time.
By the way that´s my hunting load,lil change I use Nosler Ballistic Tip.

 

[Antelope_Sniper]

Did you change anything else such as brass or primers?

 

[colt45]

only thing changed is the lot number on the powdder can. The primers are from the same lot of 1000, brass is twice fired full lenght sized. I have had afew differences in the past but nothing this big. on the pluse side of things it was a smaller group

 

[Antelope_Sniper]

Wow, that is a big difference.
I've never had that much of a difference on a normal cannister power before, but powder lots will vary, and sometimes they vary enough to get sold as surpluss.

Some old boys from my range said there was a pretty significant difference between some of the Hogdons powders (specifically H1000) after they stopped making them in Scotland, and started buying them from Australia. Sometimes powders are reformulated a bit, and considering all the recent advances in powder tech, that wouldn't suprise me...This just might be a good reminder for all of us to be a little careful...

 

[colt45]

I guess i'll load the rest of them and rezero the rifle
thanks for listening

 

[JD338]

I have seen differences in group size, location, and velocity but never to this level. Resight your rifle to the new powder and be happy, you got a higher velocity and a smaller group. :lol:
You may also want to pick up a couple more pounds of the same lot for future hunting loads. :wink:

BTW, that is a great load, I have used it myself but with the 140 gr PT and BT.

JD338

 

[colt45]

JD, I haven't though about gettin more to put up now I have to make a trip back to the store :grin: but I did notice the gains :wink:

Thanks again everyone

 

[FOTIS]

OK, Variations up to 10% either way (velocity hence pressure, accuracy barrel harmonics etc) is normal for modern day powders.


Cartridge : .280 Rem.
Bullet : .284, 140, Nosler AccuBond 59992
Cartridge O.A.L. L6: 3.330 inch or 84.58 mm
Barrel Length : 22.0 inch or 558.8 mm
Powder : Alliant Reloder-19

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 83 45.60 2327 1683 29572 9290 84.3 1.451
-18.0 85 46.74 2387 1771 31545 9629 85.8 1.412
-16.0 87 47.88 2447 1861 33648 9963 87.2 1.374
-14.0 89 49.02 2508 1955 35883 10291 88.6 1.338
-12.0 91 50.16 2568 2051 38297 10611 89.9 1.300
-10.0 93 51.30 2630 2150 40864 10922 91.1 1.260
-08.0 95 52.44 2691 2252 43612 11224 92.3 1.222
-06.0 97 53.58 2753 2356 46554 11514 93.3 1.185
-04.0 99 54.72 2815 2464 49708 11791 94.4 1.149
-02.0 101 55.86 2877 2574 53092 12054 95.3 1.114 ! Near Maximum !
+00.0 104 57.00 2940 2686 56726 12303 96.2 1.081 ! Near Maximum !
+02.0 106 58.14 3002 2801 60633 12534 97.0 1.049 !DANGEROUS LOAD-DO NOT USE!
+04.0 108 59.28 3064 2919 64839 12748 97.7 1.018 !DANGEROUS LOAD-DO NOT USE!
+06.0 110 60.42 3127 3039 69371 12943 98.3 0.987 !DANGEROUS LOAD-DO NOT USE!
+08.0 112 61.56 3189 3162 74249 13118 98.8 0.958 !DANGEROUS LOAD-DO NOT USE!
+10.0 114 62.70 3252 3287 79489 13271 99.2 0.930 !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 104 57.00 3094 2976 68115 12354 99.7 1.000 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 104 57.00 2741 2336 46341 11636 88.7 1.185

 

[buckfever]

Thats the same load I load for my wifes 280 her Ruger gets 2970 fps with pts and some how she shot a three shot group at a 100 yards that measured .266 :shock: and that was before the new trigger :? and she's never done that again

 

[old #7]

I don't understand why your groups are shifting that much with a 20fps difference.
I have loads that have an E.S. of 20fps and shoot very tight.
Maybe you stumbled on a sweet spot in your barrels harmonics??

 

[FOTIS]

Maybe you stumbled on a sweet spot in your barrels harmonics??

looks like it!