tacosupreme
Member
It's kind of funny, for a cartridge that has been around for almost 150 years reliable load data is sure hard to come by. This is especially true when finding loads compatible with the Magnum Research BFR. Look at the bullet mfg website and the data is completely different than the powder mfg, and different yet again from the internet lore on various lever action fanatic forums. During load development I found some dangerous published load data, and not because of too much powder. The case capacity on the 45-70 is substantial. Most trap door level loads are quite light and fill the case to 50% or so. That seems reasonable until you get a hangfire, which has happened to me 3 different times with "safe" loads published in well known and trusted sources. Why that happens is unknown to me, but my theory is that the powder is laying in the bottom of the case so that the flame from the primer skims the surface instead of blasting into the kernels. Either way, I'm avoiding light loads from here on out. Here are the loads that actually work for me, in my 45-70 BFR with a 7.5" barrel at 30F and 5800' elevation.
(Low pressure plinking load)
Starline brass
Federal gold medal match magnum GM215M primers
Oregon Trail 405 grain .458" hard cast bullets
45 grains of Varget (started at 40, worked up. Max is 55 grains or so compressed)
2.530" COAL with a medium crimp in the last cannelure.
Great accuracy, hard hitting, low recoil load. A little dirty, leaving some powder residue in the cases. Reliable ignition (tested down to 6F)
(hunting, rock bustin' load)
Everything above is exactly the same except the charge is 49.5 grains of IMR 3031 powder. This is not pleasant to shoot. I fired twenty rounds in a row and a week later every joint in my right arm is sore, including my clavicle for some reason. If you hand your pistol to a seasoned big bore pistol shooter they will take one shot and politely set it down. I have yet to see anyone fire more than one round of this load. Penetrates around 18" of green pine and I have no doubt would pass through any north American game mammal the long way. 1" groups at 50 yards, at least until you start flinching.
(light game/deer load, under 100 yard)
Starline brass
Federal gold medal match magnum GM215M primers
Hornady 250 grain MonoFlex
50 grains of H322
2.650" COAL with a medium crimp on last cannelure
(DANGER this load is too long for marlin lever guns, Hornady factory loads these much shorter so they will feed!)
Very mild recoil. Could probably get a lot more out of this load with more powder, but accuracy is great and you can shoot it all day and not be sore. Drops like a rock past 100 yards. Good deer/hog load without the over penetration issues of the hard cast bullets above. Reliable ignition in all conditions.
That took me a long time to get right. There just isn't much data out there for BFR guys. I use RCBS cowboy dies and I do use the crimp feature. You should too, as the stiff recoil will move the bullets around without it.
39585335_10161305094700131_3377247627975327744_n
IMG_3952
(Low pressure plinking load)
Starline brass
Federal gold medal match magnum GM215M primers
Oregon Trail 405 grain .458" hard cast bullets
45 grains of Varget (started at 40, worked up. Max is 55 grains or so compressed)
2.530" COAL with a medium crimp in the last cannelure.
Great accuracy, hard hitting, low recoil load. A little dirty, leaving some powder residue in the cases. Reliable ignition (tested down to 6F)
(hunting, rock bustin' load)
Everything above is exactly the same except the charge is 49.5 grains of IMR 3031 powder. This is not pleasant to shoot. I fired twenty rounds in a row and a week later every joint in my right arm is sore, including my clavicle for some reason. If you hand your pistol to a seasoned big bore pistol shooter they will take one shot and politely set it down. I have yet to see anyone fire more than one round of this load. Penetrates around 18" of green pine and I have no doubt would pass through any north American game mammal the long way. 1" groups at 50 yards, at least until you start flinching.
(light game/deer load, under 100 yard)
Starline brass
Federal gold medal match magnum GM215M primers
Hornady 250 grain MonoFlex
50 grains of H322
2.650" COAL with a medium crimp on last cannelure
(DANGER this load is too long for marlin lever guns, Hornady factory loads these much shorter so they will feed!)
Very mild recoil. Could probably get a lot more out of this load with more powder, but accuracy is great and you can shoot it all day and not be sore. Drops like a rock past 100 yards. Good deer/hog load without the over penetration issues of the hard cast bullets above. Reliable ignition in all conditions.
That took me a long time to get right. There just isn't much data out there for BFR guys. I use RCBS cowboy dies and I do use the crimp feature. You should too, as the stiff recoil will move the bullets around without it.
39585335_10161305094700131_3377247627975327744_n IMG_3952
