Couple of things to mull over to get good accuracy out of a Win 94. I have shot lots of cast in my various 94's and once all the bases are covered they shoot amazingly.
1. What is your over all max length for your ammo/bullet combo? Take a cleaning rod and with the rifle pointed up, #### the hammer (no ammo in it of course) and drop the cleaning rod down the barrel until it stops. At the muzzle make a mark with a felt pen on the cleaning rod. Now take one of your cast bullets and with your finger (this is kind of hard on a lever action) and the rifle pointed down put the bullet into the chamber so that it is just sitting in the barrel. Put your pinky into the chamber to hold the bullet in there, with it still held in place raise the rifle and sit it in your lap and with the cleaning rod again put it down the barrel until it just touches the bullet in the barrel. Have someone mark this line on the cleaning rod. This is your new max cartridge over all length minus 1 thou . Now the problem with any lever is it has to cycle thru the action, a bolt action is a little bit more forgiving in this area. Make up a dummy round with just the cast bullet in an empty case and to the max length that you measured minus 1 thou. Drop the dummy round into the chamber and see if it closes. It should close with maybe a slight amount of force at the end on the lever closing or just like factory ammo, no force at all. If this worked then go to the next step, if it doesn't then put the dummy round back into the press and push the bullet down 1 more thou and repeat until you can chamber correctly. Now that it chambers OK, run it thru the action and see if it binds. Load it into the tube and try and cycle the action. Does it work? If it does stop and you are set, if it doesn't it goes back into the press and pushed into the case another 1 thou until it cycles thru the action with no problems. This is the correct bullet/case dimension for your gun to try and achieve the maximum accuracy. Write this number down so you can refer to it, trust me you will forget. Amazing how some people have never done this with any of there reloads, they just look at the max over all length in the reloading books and adjusted to that measurement. They have spent many hours at the range and finally come up with a combination that works when if they had done this first would have saved countless rounds and time and aggravation.
2. Size of your bullet. Slug the barrel. You can take one of your cast bullets and make it out of pure lead or as near as possible and use it as a slug. I put a pure lead bullet into my vise and squeeze it ever so slightly from nose to base, enough to make it get fatter in the middle, not much but at least a couple of thou over what you expect it to be. I clean the barrel and oil the barrel with lots of oil. Take your fat bullet and put the nose in the barrel and with a plastic hammer (piece of wood hit with a regular hammer is fine) drive the bullet into the barrel. Now drive it down with an old cleaning rod/piece brass dowel etc. Once the bullet drops out into the chamber take it out and measure it. In my 30-30's the dimensions vary from .308-.310 depending on the way they came from the factory. I always go 1 thou over this measurement for my bullet sizing and sometimes 2 thou. I size my 30-30 bullets to .311 and have had no problems at all. If your bullets are dropping from the mold to small for your barrel then you can add little pieces of aluminum foil (you can buy muffler repair tape that is nothing more than aluminum foil at Can. Tire) on each half of the mold to gain as much at 2 thou over diameter without leaving fins on the bullet. It is called beagling a mold. Crank up your casting temp and add more tin/antimony to your mix and this also increases the size of your bullets without beagling sometimes.
With the correct AOL of your ammo and the correct bullet size the next step is the lube on the bullet. Lots of people love Lee Liquid Alox others love Carnuba Red, NRA 50/50 etc. You will have to experiment a bit to find what you like. In general as long as the bullet is sized correctly and not pushed to hard over 2000 fps the lube you choose will work. No leading and your happy.
We have covered 50% of the reasons why your 30-30 wont shoot straight without leaving your bench. Another 30% I would say is the bullet itself. Is it round, flawed, have hidden voids inside it, did you weigh all your bullets and make sure they are within a grain or two either way of the norm. Is the gas check on straight and not cantered. As long as all these things are good it should shoot ok.
The remaining 20% I would say is human error and rifle. How does the rifling look inside the barrel, warn or ok? Have you accurized your 94? Nothing binding on the barrel? Are the barrel bands rock solid and causing your barrel to bind. When you start to shoot and make it hot it will be all over the place if this is not taken care of. There are lots of info on how to do this on the Internet so I won't go to deep but basically you are removing any stress the barrel bands are putting on the barrel by removing a thou or two from the inside of the band ring so that it is still snug but not tight. As you shoot it barrel heats up and if the bands are to tight then the barrel starts to bend and accuracy is out the window.
I bought a used 30-30 off of a neighbor that said it wouldn't hit the broad side of a barn and I could have it for 100 bucks and said I could use it for parts because that is all it was good for. The barrel bands were so tight I literally had to knock them off with a hammer and brass punch, and I wasn't giving them a love tap either to get them off. Once I relieved the added stress , did my usual max over all length with my 311041 bullet and loaded up 9 grn of Unique and worked up to 12 grn, I settled on 11.3 grn. Amazingly I could get .8"/5 shots from the rifle at 50 yards. I in fact took it gopher shooting and had lots of fun with the old 94. I showed him a target from the range that had 10 shoots on it and it measured 1.1" with 8 of the 10 and two flyer's to spoil it to the 1.1".
Once you have taken care of the little things that I have described you will find that the 30-30 will shoot just fine and dandy.