Awful accuracy out of 45-70 handloads. Good accuracy out to store bought.

[Bad Ass Wallace]

I use a load of 36.5gn of 3031 in my 1886 x 45/70 with a 420gn Hensley & Gibbs boolit. This group at 100yds with a receiver sight.

As others have said your loads are way too hot!

[Goofy]

Kinda sorta of the thought that the -70 part of the cartridge nomenclature says a lot. If one follows that path with soft plain base bullets a new horizon may await.



The top row is 30:1 @ 530 grains




As others have suggested, there is a corollary between alloy, size and pressure.

[Yooper003]

I shoot the Lee 340 RN in my cva scout V2 one of the first guns I cast for. The mold is a .457 & that is why I got into powder coating too add some size to these boolits. After pc I run them through a .459 die. Probably the most accurate plinking load with this boolit for me is 11-11 1/2 gr, red dot he best fast load in this gun with this boolit is 50 gr. Of Varget. Yes factory Hornady 325 leverevolution are very accurate but prefer to shoot the cast boolits for both plinking & hunting.

[MostlyLeverGuns]

Need to reduce load. Plain base won't do much more than 1200 fps without accuracy loss. NORMALLY a gas check is needed to push bullets faster. Uniform sizing may help and weight sorting can make a difference. Bullet hardness can make a difference but you are just going too fast for that plain base bullet. In the 45-70 you could use an upside down gas check, but that is a different exercise that includes annealing and sizing gas checks. A lubricated card wad can help but again a different exercise, same with powder-coating. Light loads 10 grains of Red Dot or some others pistol powders, I use HP38, will give better accuracy and are 'more fun' with that bullet.

[Petander]

To the OP,how do you expand the brass?

The other thing I noticed when I was getting fliers with my first try at cast was I had some uneven boolit bases.

I also started my casting career with 45-70 and had horrible results. At first my Lee bullet was undersize, then I bravely lapped it bigger but my "expanding" was only flaring the brass with my Hornady die... so I ruined my bullet bases by shrinking them to undersize when seating them. Bad.

You need a proper expander. I don't know what you have but have you pulled a seated bullet and measured the base?

FWIW ,here is my fastest load , a plain base Hi Tek coated 325 RCBS @ 2000 fps. Using a .458 NOE expander with a .459 bullet. Alloy ~ 15 bhn. Marlin SBL.

I like it fast for shooting moving moose target practise, aim at the beard @ 100 meters with this for a lung shot.

I have NOE expanders for every cast thing I load now. Even more in the mail right now...

[Chemoman]

your rifle is a 1/20 twist. you should be shooting a 400 to 450 grain bullet. otherwise it can gyro out and get you fliers. the lighter bullet is too small for that twist in weight. dont make them so hard, size them to .458. this may sound strange but put a 60 thousands wad behind the bullet either hard fiber or poly type. prevents leading and become a perfect base for the bullet also. dont make them go faster than 1800 ft. per second out of the muzzle. doing all of the above will get you shooting very good groups. of course use a good lube. make sure your barrel has no leading in it when you test again. again your bullet is too small and gyros out.

[725]

My .45-70 load with a 415 gr. 460420 boolit is 40 grains of 3031. More than enough!