45-70 loads.

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amosfella

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I just got a marlin guide gun in 45-70 with the 18.5 inch barrel. I was wondering what powders are good for it. I have universal, clays, 1680, imr 4064, imr3031, benchmark, h322, and supreme 780. I'm guessing that with the shorter barrel, one would want a faster burning powder rather than a slower one.
also confused. For h322, my lee book lists the starting and never excede load as being 57gr. My lyman book lists the load as 49-56.7 gr or something like that.
 
3031 is a very popular powder for 45-70. Many also use 4198. I'm not sure how long you need for the powder to burn properly but lots of people use both these powders in everything from 18.5" guide guns to 26" single shots so I can't see you going wrong with either. Generally with any cartridge in at least 18" of barrel, powder speed doesn't mean much. Unless you are loading really slow magnum powders into a 10" barrelled gun you don't have anything to worry about.

Different books will have different starting and max loads based on brass used, chamber dimensions, barrel dimensions, barrel length, lot of powder, and a pile of other variables. Either starting value should work so long as they are up-to-date but when I run into situations like that I tend to start at the lower of the two.
 
Don't forget that there are three different unofficial pressure levels for 45-70. Generally level 1 is for black powder rifles meant for black powder pressures. Level 2 is for modern lever rifles. Level 3 is for single shot dropping block or Mauser action rifles. The official maximum pressure for 45-70 is 28,000 CUP according to SAAMI in case the ammo if accidentally loaded into an old rifle meant for black powder cartridges but there is load data up to 50,000 CUP for much stronger actions. Each reloading data publisher doesn't necessarily use the same pressure range for the same level meant for the same type of firearm.

If Lee's starting load is higher than Lymans max load, is Lee's load data for a modern lever rifle and Lymans for black powder pressure? My Lyman manual, Lyman cast bullet manual, and the Hodgdon online database all have three different sets of load data for 45-70 for different pressure ranges.
 
Lee lists the 3 power levels and basically uses Hodgdons data supplemented with a couple other powder mfr's. But remember the test data that determined that max load was with one specific rifle, primer, case etc so it may or may not be the max for your rifle. The key is starting low and work up. I like IMR and H4198 with both of Hornadys 350 jacketed bullets. With a max charge of 50 grs IMR4198 and a 350 FP in win brass/cci 200 primers I get just a hair over 2000 fps out of my 18.5" guide gun. Book velocity is 2132 fps so that's pretty good considering test barrels are usually 24". As always, work up your load, do not just plug mine in and go. With a decelerator pad those loads aren't too bad at all. I fired a 350RN into some rotted wood and with a couple pieces of stuck-on wood it weighed 326 gr. Distance was about 10 yds. That's pretty good if you ask me.
 
12 grain's of unique work well for all

350 grn bullet 19 gr. of Trailboss is max load, starting load is 13 grn.

450 grn bullet 16 gr. of Trailboss is max load, starting load is 11 grn.
 
I've also used 3.4cc (14.5 gr) trailboss under a Hornady 300 JHP for 1098 fps and recoil like a .22 mag. My SKS has more recoil :). What really surprised me was the consistency. 3 shots over the chrony went 1098, 1098, 1079 fps using a Lee dipper to charge the cases. I've never seen that using Lee dippers, they usually vary up to a full grain from dip to dip with most powders. I'll be looking for some unique to dabble with as well.
 
And then there is old-fashioned SR-4759, in production for close to a century and still steamin' along.

You can duplicate ANY Black powder RIFLE load with SR-4759 simply by multiplying the Black Powder charge by point thirty-eight.

For a .45-70 that is (70 x .38 =) 26.6 grains.

For a .32-40 you would use (40 x .38 =) 15.2 grains.

For a .43 Mauser it is (77 x .38 =) 29.3 grains.

For a .577/.450 Martini-Henry (or a Gardner & Gatling .450 Mark I) it is (85 x .38 =) 32.3 grains.

For a .45-140 Sharps that is (140 x .38 =) 53.2 grains.

No wads or filler are necessary; the powder is VERY bulky.

You get original ballistic performance at Black Powder PRESSURES..... and no clean-up afterwards.
 
IMR 3031 was the first powder I tried. 46gr under either a 400gr Speer or 405gr Rem FNSP. I've tried Reloader 7, 4198 and benchmark since but have just stuck with 3031 for all my hunting and shooting with the 45/70. Partly because I have 10lbsof it and partly cause it works so dang well :)
 
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