IMR 4198 is an excellent mainstay powder for the 45-70. I shot this powder today but loads just under max. All grouped ok at 1 to 1.5 inches at 50 yds. 250g MonoFlex grouped best at 1 inch and SD was 5.3.
Three Shot groups taken at 50 yds with Ruger Marlin 45-70 SBL 19 inch Barrel : Hornady Manual used 22 inch barrel.
UPDATE: I also included Momentum calculations.
https://calculatorfriend.com/bullet-momentum-calculator
Hornady 250g MonoFlex Best Group
Load 47g Manual says vel 2100 fps
Avg Vel. 2080.5 fps Diff manual vs actual 20fps
SD 5.3
Muzzle Energy 2444 ft-lb
Bullet Momentum 10.27 kg·m/s
Note for comparison: A 175g 7mm bullet traveling at 3000fps has a momentum of 10.37 kg.m/s. Identical to this load. Hmmm!
Hornady 300g FNHP
Load 46g manual says 2000 fps
Avg Vel.1900.5 fps Diff manual vs actual 100 fps
SD 34.1
Muzzle Energy 2438 ft-lb
Bullet Momentum 11.26 kg·m/s
Hornady 350g RNFP
Load 43g Manual says 1800 fps
Avg Vel 1761 Diff manual vs actual 39 fps
SD 9.4
Muzzle Energy 2445 ft-lb
Bullet Momentum 12.17 kg·m/s
I shot a 400g FP and found the MV at 1413 fps. Momentum was 11.16 kg·m/s. Lower than the 350g due to significant velocity differences. To equal the 350g momentum, the 400g bullet needs a velocity of 1550 fps.
Thus, the 350g appears better at penetration than the 400g at 1413 fps and the 350g has a flatter trajectory.
Conclusion: 250g MonoFlex with 47g is best load of these. The 350g Load comes in second. The 300g load was worst. The 300g loads need work to find best loads with different powder.
I do like the MonoFlex all copper said to retain 95% of weight and won’t over mushroom on deer.
On bear, it looks like the 350g Round Nose Flat Point would be a great black bear round with minimal mushrooming and great momentum/penetration
Good Shooting!





















My Browning 26 inch 9.5 twist rifle barrel likes hand loaded 7mm 168 grain Nosler ABLR with a hot load of IMR 4831 per Nosler web load data. I chrono’d an average of 3005 fps. Wow! These are cookin’ !! COAL was 3.255 inches. No pressure signs except the primer was a bit flatter… as expected. Three rounds measured 3/4 inch but more testing will firm that up. I will change the trigger to a Timney at some point as it is impractical to easily adjust with a 2mm Allen wrench on a sealant filled screw. If you like 4 pounds for a factory trigger it works, for some hunters, not me. All my rifles are set near 3 pounds. 
