IMR 8208 in 45-70

[Alaska]

Just acquired a Marlin Trapper 45-70
16.5” barrel

I plan on using Speer 350gr FN for Bear/moose.
And IMR 8208 in WW cases with Fed 210M primers
2.600” coal

Any load data using IMR 8208 ?
It does so well in my 5.56 with 77MK and 308 win with 150gr.

 

[JD338]

Jeff,

I've only used H322 in my 1895G with 300 gr and 405 gr bullets. Excellent speed and we'll under MOA accuracy.

JD338

 

[Alaska]

Yes used H322 years ago when I first started reloading the 45-70 good results also with 3031:4198:RL 7. Stayed with RL 7 now I am hearing good things about 8208 in the 45-70.

 

[Alaska]

Yes used H322 years ago when I first started reloading the 45-70 good results also with 3031:4198:RL 7. Stayed with RL 7 now I am hearing good things about 8208 in the 45-70.
Since I use it in my 5.56 with 77 MK ......I have some on hand.

 

[DrMike]

Cartridge          : .45-70 Govt. SAAMI
Bullet             : .458, 350, Speer FN 2478
Useable Case Capaci: 57.117 grain H2O = 3.709 cm³
Cartridge O.A.L. L6: 2.550 inch = 64.77 mm
Barrel Length      : 16.5 inch = 419.1 mm
Powder             : IMR 8208 XBR

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   82    43.29   1488    1721   20578   3993     71.4    1.456
-09.0   83    43.77   1504    1759   21121   4063     72.0    1.439
-08.0   84    44.25   1521    1798   21680   4133     72.6    1.422
-07.0   85    44.73   1538    1837   22254   4204     73.2    1.406
-06.0   86    45.21   1554    1877   22844   4274     73.8    1.390
-05.0   87    45.70   1571    1918   23452   4345     74.4    1.374
-04.0   88    46.18   1588    1959   24076   4415     75.0    1.358  ! Near Maximum !
-03.0   89    46.66   1605    2001   24718   4486     75.6    1.343  ! Near Maximum !
-02.0   90    47.14   1622    2044   25378   4556     76.2    1.327  ! Near Maximum !
-01.0   90    47.62   1639    2087   26057   4626     76.8    1.312  ! Near Maximum !
+00.0   91    48.10   1656    2130   26756   4697     77.3    1.297  ! Near Maximum !
+01.0   92    48.58   1673    2175   27474   4767     77.9    1.282  !DANGEROUS LOAD-DO NOT USE!
+02.0   93    49.06   1690    2220   28214   4836     78.5    1.268  !DANGEROUS LOAD-DO NOT USE!
+03.0   94    49.54   1707    2265   28977   4906     79.1    1.253  !DANGEROUS LOAD-DO NOT USE!
+04.0   95    50.02   1725    2311   29762   4976     79.6    1.239  !DANGEROUS LOAD-DO NOT USE!
+05.0   96    50.51   1742    2358   30569   5045     80.2    1.224  !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     91    48.10   1774    2445   31726   5125     85.9    1.206  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     91    48.10   1524    1806   22336   4137     67.3    1.402

 

[Joec7651]

If 8208 is what you’ve made up your mind to use then it will do just fine. You won’t get the velocity needed from that powder with a Speer 350gn FN however. I use that bullet but it’s designed for .458 WM and is very tough. It’s a great bullet btw. You’ll have much better results with IMR or H4198. They yield much more velocity, which is what that projectile is designed for. On the up side, you’re starting with a half inch hole even without expansion.

 

[Guy Miner]

The 350 gr Flat Nose Hornady was the original bullet for the 450 Marlin.

I think it was the 350 gr Round Nose Hornady that was designed for the 458 Win Mag.

According to Dr Mike's chart, it looks like 8208 will get you about 1650 fps mv, about the same as a middling charge of RE-7 will do with a 405 gr bullet as I recall. I used 45 gr Reloader 7 and a Remington 405 gr Soft Point from my old 18.5" Guide Gun. It worked well.

Guy

 

[1Shot]

IMR 4198 and RL7 are about the best 45-70 powders if you want higher velocity. I and some friends have had great luck with IMR 4198 for years. A Sierra 300 gr HP with a stiff dose of IMR 4198 is a deer smasher.

 

[Alaska]

This is Their data
Pressures good too

 

[Guy Miner]

Yup, that's right up there with what I'm seeing with their IMR 3031 and IMR 4198 data.

2,000 fps - 2,100+ fps with the 350 gr Hornady is certainly possible.

Those loads are fun! For a bit.

I do have some 45/70 ammo loaded to that level, take them with me when I'm camping in bear country, and keep the big bore Marlin handy. I really ought to take that rifle on a bear hunt.

Guy

 

[Alaska]

Yes used RL 7 for years in GG @ 51.8 with 350 Hornady RN
2000 FPS load good bullet and very accurate. With all the new powders out
IMR 8208 sounds like a top choice also
Plus it has decopper addictive which I like.
Now I have a Trapper with 16.5” I know the 2000 FPS is unobtainable in the short barrel.
I will probably just stick to my 350gr Hardcast FNGC bullets.

 

[Guy Miner]

Are you still hunting up in Alaska here in late October? Or is that pretty much over for now?

I've never been later than mid-September in Alaska. Winter was clearly on the way. :mrgreen:

Guy