Sizing bullets for my Marlin 45-70

[woody402]

I have a Marlin 45-70 guide gun I'm going to start loading for. I picked up a Ranchdog 460310 mould in the classifieds that I plan to use. I cast a few and slugged the bore. They measure .457. My question is where should I start for sizing of the bullets? I plan on getting either a Lee .457 sizing die or a die for my lyman sizer. Lee only makes the .457 but was thinking a .458 might be better. The bullet drops .460 from the mold. Looking for a starting point. Thanks.

[Iowa Fox]

If the 460 will chamber shoot them at 460. Marlins like them fat.

[HNSB]

My 1895 also slugged at .457.
I flapped my .457 sizer out to .4585. I've shot several of those at just over 1500 fps with no leading, but all the same, I might take it up to .459.

[Scharfschuetze]

.459" boolits works well in My 1895 Marlin with the Ballard rifling.

[woody402]

My gun has micro groove rifling.

[farmerjim]

Use emery cloth, a rod ( I use a wood dowel with a slit cut down the middle to hold the cloth) and a drill, to open the Lee die to what you want. It only takes a few minutes. Go slow at it and check the size of the boolits pushed through every 30 or so seconds of grinding. I use a .459 for my 45-70.

[woody402]

Use emery cloth, a rod ( I use a wood dowel with a slit cut down the middle to hold the cloth) and a drill, to open the Lee die to what you want. It only takes a few minutes. Go slow at it and check the size of the boolits pushed through every 30 or so seconds of grinding. I use a .459 for my 45-70.

I might do that. Done it to a few .357 dies. I kind of want to stick with the Lee die. So I may just lap it out to .458

[Keyston44]

My Marlin Guide Gun slugs at 457 also. I size my Ranch Dog 425 gr bullet to 460 when I'm pressing on the gas checks. My Lee 457-405-F drops bullets at 459 so I shoot them as cast.

Key

[BABore]

If your Marlin 45-70 is slugging at 0.457, I would like to know the following;

are you using a pure lead slug for slugging, preferrably a hollow egg sinker so there is little to no springback?

have you slugged just the muzzle only to look for bore constrictions?

are you using a micrometer to measure the slug?


I ask cause most all of the 45-70's I've slugged run just a shade over 0.458. The chamber will typically allow a boolit diameter of 0.460 to 0.462 diameter.

[woody402]

I was using pure lead and a micrometer. I think I'm going to start with a .459 and go from there.

[FishingFool]

I use .459 for both of my marlins and all my buddies single shot NEFs for primitive this year.

[waco]

If the 460 will chamber shoot them at 460. Marlins like them fat.
What Fox said.....