45-70 BFR load data

Discussion in 'Reloading' started by tacosupreme, Dec 9, 2018.

  1. tacosupreme

    tacosupreme Member

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    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.

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  2. yorke-1

    yorke-1 Well-Known Member

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    I had a 10" 45-70 BFR and I just started with low end lever gun loads and worked up until it stopped being fun to shoot. I ended up with 300gr bullets at 1820fps an 440gr bullets at 1610fps. The BFR will take heavier loads than your wrists will, so there's really no limit. IMR 3031 and H4198 were my favorite powders. If you haven't played with Trailboss yet, grab some and give it a try.
     
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  3. tacosupreme

    tacosupreme Member

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    The problem I found with the low pressure loads sometimes wouldn't ignite, or would hangfire. Click, ffffffshhhh, bang. Frightening. I didn't use any fillers, but the manuals did not call for it either. I'm really liking Varget as far as recoil impulse goes, and I might start increasing charge densities with that and see what happens. The revolver is certainly more capable than I am. I do need to try some Trailboss.
     
  4. yorke-1

    yorke-1 Well-Known Member

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    I had the same issue with some powders when I had a 45-70 Contender that needed low-mid power loads. I had good luck with Reloader 7 with the low end charges.
     
  5. tacosupreme

    tacosupreme Member

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    That was one of the powders I had problems with. I was using CCI large rifle primers and Hornady 300 grain hollow points and couldn't get the trapdoor level loads to ignite in cold weather. On warm days it seemed to work fine. I swore off both the primers and powder. I got the load from Alliant powder website. I read somewhere that RL7 works better with heavier bullets and there are other reports of failure to ignite with similar loads.
     
  6. RT2506

    RT2506 Well-Known Member

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    Get you some Accurate 5744 powder for the light loads. It is not position sensitive. I have used it with lots of different bullets in rifles. I loaded some 300 Hornady HP for my cousin that has a BFR. I don't have the data close at hand but it was a middle of road load from the Accurate manual. It shot good and was about all he wanted to handle. This powder burns kind of dirty with cornels' still laying in the bore looking like the powder did not burn but it did burn it is just dirty burning. I have gotten some outstanding accuracy with this powder with cast bullets.