quickload data for 24n41 270 weatherby 1:7 twist .600" throat.

[assasinator]

this length is .189" off of the lands. i always intended to rechamber to 270 weatherby and shoot 150 to 175gr bullets.

i have 270 weatherby dies and brass already. i could never get these kinds of possible results with the 270 win. as long as it betters the 6.8 western, that was always the goal.

bullet touchup at the lands is 3.89" COAL.

this length is only for the 175 sierra TGK.

Cartridge : .270 Weath. Mag.
Bullet : .277, 175, Sierra TGK 4475
Useable Case Capaci: 74.432 grain H2O = 4.833 cm³
Cartridge O.A.L. L6: 3.700 inch = 93.98 mm
Barrel Length : 27.0 inch = 685.8 mm
Powder : Vihtavuori 24N41 *C

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 60.80 2294 2044 29530 9745 81.1 1.853
-18.0 85 62.32 2358 2160 31661 10129 82.7 1.803
-16.0 87 63.84 2423 2281 33959 10509 84.4 1.755
-14.0 89 65.36 2488 2406 36438 10882 85.9 1.707
-12.0 92 66.88 2555 2536 39118 11246 87.5 1.650
-10.0 94 68.40 2622 2670 42017 11601 88.9 1.595
-08.0 96 69.92 2689 2810 45157 11943 90.3 1.541
-06.0 98 71.44 2757 2954 48564 12272 91.6 1.489
-04.0 100 72.96 2826 3103 52265 12586 92.9 1.439
-02.0 102 74.48 2895 3257 56293 12881 94.0 1.390 ! Near Maximum !
+00.0 104 76.00 2965 3416 60686 13157 95.1 1.343 ! Near Maximum !
+02.0 106 77.52 3035 3579 65484 13412 96.0 1.297 !DANGEROUS LOAD-DO NOT USE!
+04.0 108 79.04 3106 3748 70741 13643 96.9 1.253 !DANGEROUS LOAD-DO NOT USE!
+06.0 110 80.56 3176 3921 76507 13848 97.7 1.210 !DANGEROUS LOAD-DO NOT USE!
+08.0 112 82.08 3248 4099 82816 14025 98.4 1.169 !DANGEROUS LOAD-DO NOT USE!
+10.0 114 83.60 3319 4281 89751 14173 98.9 1.129 !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 76.00 3138 3826 74205 13290 99.3 1.234 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 104 76.00 2744 2926 48716 12320 86.6 1.482


the barrel gets rechambered tuesday. encore, so no setback. i believe Roy decided this chamber dimension to clean up 270wichester barrels.

-bill

 

[Dmagna]

50 BMG powder is a little slow. But have at it.

 

[Seabeeken]

Seems to be an answer to a question that wasn't asked or did I miss something. It is slow burning but that seems to be the way these days

 

[assasinator]

so sea....no. super slow powders are for WAY overbore cartridges in a lot of calibers.

this powder is suitable based on data i posted from quickload. its suitable for one bullet at this time. there are rumors of 180 grain .277 bullets.

so, for a 175 sierra tipped game king that is seated VERY long for my chamber where there is very little bullet freebore.

this powder works very well for heavy bullet 338 norma and 338 lapua, as well as 375/416 cheyenne tactical with heavy bullets.

i tried it with 175 TGK long seated 270 winchester and it didnt burn. i bought it with 270 weatherby and heavy bullets. OVERBORE with enough powder makes fast 50bmg powders work.

i posted the quickload data as a baseline. magpro, h1000, retumbo, and 24n41 can work for my purposes. i have been experimenting with non traditional loads for 36.5 years.

as a matter of fact, the 40 year gunsmith who is rechambering my encore 270win barrel does the same thing. he has me beat, but he likes big bore belted mags, 458 lott, 458 win, many belted mags, and lol 204 ruger. he asked me why i still waste so much powder. i cant help it.

so to answer, slow powders are specific to the application. i use 3031 for my 3050FPS 205 grain 375 taylor with large rifle primer. itis NOT advisable to try things without a lot of experience. it can POP your gun.

too low of a charge can blow your gun. to big a charge that is too fast is worse. seating a bullet into the rifling causes to high of a pressure to start bullet movement. it is all dangerous. slow powder doesnt lower the risk.


stick to the reloading manuals. stick to the advice of long time members in this forum. stick to loaddata.com IMO.