Cartridges of the World has cartridge dimensions listed for the 
.577 Snider, but no drawing.  As the cartridge does have a taper behind the area where the bullet seats, I need to know the point at which the taper ends, measured from the base.
Can anyone post his info or email me a cartridge drawing?
Thanks ever so much!

JC,

  Here's the dimensions as given in Ken Howells book. From the back of the rim (primer side) to the start of the shoulder is 1.3610, and from the back of the rim to the top of the shoulder is 1.4610. The angle is 7 deg. 37' 27". Subtract .0750 rim thickness if you want the measurement from the front of the rim.

  If you would like a picture of the full drawing leave me a PM with your email address and I'll take a picture of it and send it to you.

PETE

Oy say, Asst., wot rubbish!
T'awd Snider carn't kick arf so much as a full choked H & R Topper wiv slugs.  Bloody colonials!  If yer wants kick troy a 4 bore.

waterman;
24 ga brass shotgun cases are the correct diameter and are available with pockets for Boxer large pistol primers. However they are straight and must be sized down to hold the bullet. One reason I'm told "they shoot about as well as the originals"  (which wasn't very well) is the bores were much larger (.590+) than the .577 bullets used. With proper size bullets it would have to be much better.

I own and shoot a Snider artillery carbine, sporterized.  Lots of fun, but there are some things to watch out for...   
!st of all, the 24ga. shotgun brass by CBC can be reformed for use in the Snider (Just trim), the only issue is excess case capacity.   Also, check your rifle - 3- or 5-groove.  3-groove is 1:76 twist, 5-groove is 1:48 twist.  Obviously, the 5-groover is much more forgiving as to bullet selection.  Bullets need to be min. diameter .585, max. .600 (depends on the chamber - if you can call it that), .590 usually is a good compromise.  If you want to use standard (=undersized) Minies, try using an baseplug in the bullet cavity (tapered plug in the skirt, to expand the bullet).
Load her up with 80-90 grs of Fg and a bullet the right size.  If you use minies, don't use a wad.  The slow-twist rifles will also shoot quite well with round ball, but with conicals, only use the shortest (lightest) bullets.  The fast twisters can be quite accurate.  The original Snider bullets were a marvel of engineering, just to get them to stabilize in the 2 types of barrels, with hollow base and hollow nose, base and nose plugs etc. 
And finally, recoil is not that bad (A 577-450 Martini kicks harder), and they can be made to shoot with decent accuracy - it just takes a bit of work to get the ol' lady there...  But when you have watched some guys shoot a snider and score 45/50 at 200 yds, you get a different idea about the accuracy of these rifles!
They will make an excellent short-range hunting rifle.  Not to mention the looks on the range when you are chambering those howitzer shells.  Dies, bullets molds, base plugs etc. are even available  - if you want more info, just let me know...