The 40-63 and the 40-70 are two cartridges that have identical length and outside dimensions, so are listed together. The 40-63 is actually just a heavier-case version of the 40-70 factory cartridge. Both are, in turn, an outgrowth of the original 40-65 Ballard Everlasting case, which had to be handloaded. The 40-63 and 40-70 were first listed for the Ballard Perfection No. 4 and Pacific No. 5 after the Marlin Fire Arms Co. took over manufacture of these rifles in 1881. 

Lyman 403149 (330gr) 1:20 or 1:30
IMR 4198  - 22gr
1310 fps
1260 Energy
(Cartridges of the World 10th Edition)

Thank you very much. I don't have 5744 but, i have lots of 4759. Will a 20gr charge of 4759 be ok to start with?

Thank you again.

The 40-63 is a favorite of mine. I even made brass out of 30-06 back in the days. I threaded the head soldered a washer on it and trimmed to size to fit the chamber. The .477 head size was a key factor in choosing the 30-06. Oh! and the length. A lot of work but I made it go. The 40 size was a proprietary head size that was discontinued early on. So in the years we had to fabricate what we could. All the chambers I have ever run into were very uniform. I'm now fiddling with the 40-90-3 1/16 or as some have called it the 40 -90  Ideal everlasting. My favorite load for the 40-63 was 6(bulk) 4759 and 60(bulk) 1F black using a 370 grain swedged paper patched bullet. Obviously a duplex load.
40's were cheap in the 60's and 70's as previously stated because of brass. But the good thing was that all the reloading tools for them were cheap too, even molds.
I think the heritage of the 40-63 goes:
40-60 Ballard, 40-65 Ballard, 40-70 Ballard, 40-63 Ballard. The 40-60 is a very early short lived cartridge. I have a 4 1/2 with mint bore in this chambering. A very neat and rare rifle. But I have never found out just what the bullet weight was. It's 1/20 like all 40's by Marlin. I'm assuming 265 paper patched.
1 in 20 was a standard that Marlin used in all their 40 and 45 caliber Ballards.  Factory bullet weight is 330 grain but I have used the factory weight, 370 grain bullet for the 40-90, in the 40-63 with great success. My 40-63 is an A1 Mid Range.
sorry for rambling on but I do favor the 40's.
   Don   rustyrelx

Hey Rusty...about those uniform .40-63 chambers....

When I ran out of berdan primers, I gave some of the berdan cases I'd been shooting in my 1 1/2 to a friend with a nice .40-63 Pacific. The YoYo didn't think about chamber differences and this is what happened to most of 'em:
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His SN was lower than mine. They must've sharpened the chambering reamer a lot between his and mine!  

xtm

Too many decades have passed, but I don't think they had ever been fired until I acquired 'em. I fired 'em dozens and dozens of times each in my .40-63. That supply was my go-to brass for my 1 1/2 in .40-63 when proper-size primers were available. None have any headstamp, but they were a snug fit in my .40-63 chamber - so I assumed them to be .40-63. They obviously weren't snug in his .40-63!    The .40-70 brass for a Hepburn I shoot rattles around in the .40-63 chamber, so I don't think I'm mistaken about this.

I just asked him where his is marked for cal. or cartridge - on the extractor and bottom of the barrel ahead of the forend. Mine is marked .40-63 only on the extractor.

xtm

I bought 40-70 Sharps Straight brass reformed from 30-40 Krag from Buffalo Arms for my Pacific #5.  The bullet mold is stamped 40-70 SS and drops at 317 gr and .406 in 30:1.  The case head is a little undersized and I probably should have fireformed them first, but I just cut them to length and loaded them with a full case of 2F and enough compression to cover the grease grooves.  Accuracy is as good as I can manage with the Rocky Mountain sights.

I never did pursue loads with mine. Mostly because I didn't want to mount a scope on the original barrel.

I used 9.3 x 74R RWS cases.

My only load was 10.0 gr Unique. As I remember (scarey) it grouped about 5" @ 200

Frank