I loaded some 300gr cast bullets for my 45/70 yesterday with 12.5gr of Unique as my first ever cast loads. The issue I had was getting them to chamber correctly. I have a Marlin 1895 and the chamber did not want to close on these rounds for some reason. They were not longer than my normal rounds, actually a bit shorter so I could crimp it in the bottom cannelure. I had to really shove the lever very hard to get the bolt to close. Any idea what might cause this? I had these 5 cast rounds and 20 other normal rounds. My regular 20 worked as usual, but all 5 cast were hard to chamber like I said.

Wes

The ogive of the boolit might be contacting the rifling. Did you eject one after trying to chamber it to see if you had rifling marks on the boolit? It might have to be seated deeper.
The other thing to check is the diameter of the boolit. If too large, it will expand the neck of the case which is dangerous because it raises pressure. You want .002" expansion room at the neck. Measure the neck diameter of a round that chambers and compare it to a cast load. I doubt this is the problem though and would bet the boolit is being driven into the lead.
Make a dummy round so you can check it.

I will check the diameters tonight, but how could the ogive be contacting the rifling if my normal bullets aren't. The cast loaded cartridge overall length is shorter than my normal loaded lengths so if the longer ones weren't contacting then could the shorter ones?

Wes

He is talking about the ogive, to illustrate this draw 2 figures, say a triangle 2 inches tall and 1 inch wide at the base, now draw another that is boat shaped, 2 inches tall and 1 inch wide at the base. Look 1/2" down from the point and you will see the boat shaped one is wider at that point, that curve is called the "ogive"

At any rate, chamber one then eject it and see where it is shiny.

Oh, and different bullets have different ogives, to make a heavier bullet you can bring the ogive forward, to make the nose of the bullet fatter, that is why he is thinking it is bumping into the rifling.

I understand what the ogive is I believe, but as I said I don't think that can be it, the ogive are short on both bullets since they are both flat points and the cast cartridge being overall shorter. I believe the Meister cast bullets I bought were .459 instead of the normal .458, but they were listed for a 45/70. Maybe that .001 is making the difference.

If you have a tight chamber, the .459" sizing could be a problem. The best way to diagnose the problem is to coat the bullet with a sharpie or other marker, use a dark color. Then chamber a round as far as you can, and eject it to inspect the bullet.

If the bullet is seated too long, ie ogive problem, you'll see the lands engraving on the bullet, ie stipes from the rifling. If the bullet is too large in dia, you'll see scuffing the entire circumfrance of the bullet where it is rubbing on the chamber.

If the bullet is seated too long, then you'll have to seat it deeper. If the bullet is too large in dia, you can get a Lee .458" dia sizer, and re-size the bullets on your reloading press.

Are you using the roll crimp in your sizing die? With a cast bullet you may need to get a Lee Factory Crimp die to taper crimp the cartridge. This die will put the case back to factory dimensions and put a wonderful crimp on the mouth, if your problem isn't the OAL of the cartridge that will most likely solve the problem.

rshooter was right. When I got home I could see how much longer the ogive on the cast bullet was than on my 300 and 400gr jacketed bullets. I just have to seat the cast bullet way down into the case mouth to have it sit in the chamber correctly.

Thanks for everyones help
Wes

shooter was right, but I still am not sure why the longer ogive will not go all the way into the gun chamber. Let me try and draw it here:

____
/ \
| |

The above is my normal jacket bullet, has a / long Ogive.

______
/ \
/ \
| |

The cast bullet(had to draw it wider) has a 2 length / Ogive. It is LONGER I see, but it is overall a shorter cartridge and the ogive is NARROWER than the bullet base so why doesn't it go all the way in. I know I must be missing some fundamental piece of the puzzle here. I don't understand why when I seat the cast bullet deeper it inserts into the chamber fine, when it was overall shorter than the jacket cartridge to begin with.

The nose of the cast bullet is contacting either the thoat, or rifling earlier than a lacketed bullet does. this is a function of the ogive, and must be accepted for a given bullet. A lot of things you may know about reloading jacketed bullets are thrown out the window with cast bullets. Just go ahead and seat the bullet deeply enough to function, and work from there. Reduce the powder charge slightly to allow for the pressures developed by seating a bullet deeper into the case.