280ai retumbo?

[Michael Eichele]

Is anybody using RETUMBO under 160-180 grain pills in the 280AI?

Got a 28" 280AI being chambered this week and was interested in seeing what guys are using. 4831 doesn't give the volume I'd like to see. H1000 looks short as well. Thought maybe RETUMBO would give me a 100% fill density. I just don't know if it's too slow.

Any info and opinions are appreciated.

Thanks!

M

 

[MudRunner2005]

I use 7828 SSC in my .25-06 AI and .30-06 AI. I get great velocities and consistency. My .25-06 AI loads are nearly 100%, and I'd say my .30-06 AI loads are definitely compressed, but without severe pressure signs, just some slight flattening of the primers.

 

[Ridgerunner665]

I haven't used Retumbo in my 280 Ackley... But extensive research tells me it is a little "too" slow.

Reloder 26 is going to get you the best velocity and have just under 100% load density, I've put RL26 through its paces, it is very good stuff.

If I had to pick a next best for this bullet weight range, it'd be IMR7828 SSC.

RL26 is very stable in temp swings, I get .3 fps per degree using 160 and 168 grain bullets, I haven't worked with 175-180 gain bullets, don't plan to either.

7828 just might have the edge with 175-180 grain bullets.

This a calibrated QuickLoad rundown of my load: 61 grains of RL 26 under a 160 Accubond, seated to ~3.34"....I'm thinking about dropping back to 60.5 grains to ease up on the brass a bit, but I'm gonna wait and see how the primer pockets last before I make any changes....its a very stable load, I've tested it to 800 yards in a temps ranging from the teens up to 94 degrees, it does slow down a very little in colder weather, but it is very linear and predictable.

This is calibrated for 94 degrees, a hot day.

Cartridge          : .280 Ack Imp
Bullet             : .284, 160, Nosler AccuBond 54932
Useable Case Capaci: 64.438 grain H2O = 4.184 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Alliant Reloder-26 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.821% 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

-08.2   88    55.99   2789    2763   47679  11328    100.0    1.334
-07.4   88    56.49   2812    2810   49080  11375    100.0    1.316
-06.6   89    57.00   2836    2857   50520  11422    100.0    1.299
-05.7   90    57.50   2859    2904   52002  11468    100.0    1.282
-04.9   91    58.00   2882    2952   53526  11514    100.0    1.265
-04.1   92    58.50   2906    2999   55094  11559    100.0    1.249
-03.3   92    59.00   2929    3047   56707  11604    100.0    1.233  ! Near Maximum !
-02.5   93    59.50   2952    3095   58366  11648    100.0    1.217  ! Near Maximum !
-01.6   94    60.00   2975    3144   60074  11691    100.0    1.202  ! Near Maximum !
-00.8   95    60.50   2998    3192   61832  11733    100.0    1.186  ! Near Maximum !
+00.0   96    61.00   3020    3241   63642  11775    100.0    1.171  ! Near Maximum !
+00.8   96    61.50   3043    3290   65505  11816    100.0    1.157  !DANGEROUS LOAD-DO NOT USE!

 

[gunaddict]

My friend is using IMR 7828 in both of his 280 Ackley's. With 175 and 180's.

 

[JeffVN]

I use 7828SSc in my 30-06Ackley under Berger 185 juggs, and plan to start there when looking at my 7mm/30-06 Ackley using Berger 180s.

JeffVN

 

[bubba41]

my best results are with 4831 sc . retumbo my speed was off shooting 168 ablr

 

[reeldawg]

My friend has a 280 AI and runs Retumbo in it. 62.5, fps is mid 2800s and shoots in the .2s. He just started testing RL 26 and pick up over 100 fps. He is pushing 168 VLDs.


Jay

 

[orch]

Hey there,

I'm running retumbo at 56.5 grains with both 180 Berger hybrids and 175 ABLRs, using CCI magnum primers.. Started with lapua 30-06 brass that i fire formed to 280ai and finally just got some nosler 280ai brass fired today with the same load and both types of brass gave pretty much identical drops out to 1000 yards...

Speed is 2700 fps, no pressure signs, and very accurate... Base of the bullet is just touching the powder in the case but not compressing...

My gun seems to like it... I say Give it a whirl....good luck, let us know how you make out...

Orch

 

[7magcreedmoor]

I get 3015 with 168 berger and 2870 with 180 berger from my 26 inch barrels. COAL is long, and charges are a little over bergers max listed but accuracy is good.

 

[Weaselthis]

Coincedentally, I just got in from a range session today for that very round.
Bartlein 5R 9 twist at 26" w/ Vais brake.
Remmy 700 trued up action w/ Timney at 1.5#.
HS Precision stock. Sightron SIII 6x24x50 Mildot.
Nosler 280 brass fire formed first, full prep and annealed every other time.
Think this is the 4th or 5th firing. Don't have my data book handy.
CCI 200 primer. 160g Nosler Accubond (.020 off lands @ 3.505 COAL)
63.5g Retumbo
3055 fps ave. for 16 shots today. SD-13 ES-28
Smallest group was .459 MOA, largest .741MOA
This was my FIRST custom rifle and I used it for comps here in Nor Cal for a couple of years. Current round count after today is 2160. Still hanging in there!
Shot out to 900 yd. a couple of months ago. The gongs from 600-900 were in trouble!

 

[dixiemagnum80]

tagging in…...

 

[Jokostel]

Both my 280 AIs run the same loads
Brux 26 in + vias break 1-9
M48 Patriot (24 in 1-9) PACNOR?
57.5 RL17 wlrm, 140 CT (3.320) 3250 fps
60 I7977 WLR 175 ABLR OR the 180 VLD Hunting same oal, 2800fps.