45-70 ML?

[Austin from NC]

I have heard of y'all converting a 45-70 to a muzzleloader but is there a way of making a sleeve to covert it back to 45-70 so you could switch it back and forth? Just like a cylinder bore choke tube but for the chamber.

       Austin

[PHATINJUN]

Have you searched thru previous posts yet ? there is some information here.
"A 'sleeved' Shikari chamber backed by a breechplug will make it a legal muzzleloader. This does preclude its use as a cartridge gun unless the breechplug is carefully designed to be replaced with another one bored to duplicate the rear of a 45-70 case. All doable. The sleeve should closely fit the chamber walls, use a fireformed case to get rough turning dimensions from, go wide, then fine fit to your chamber. It should have a bored powder chamber of sub caliber. This makes cleaning problematic if you are used to a 'plain breech', but if, say, .375 dia. a .375 Win type jag or better yet, mop, will clean it nicely. Being sub-cal. your powder will likely overfill it and the bullet can only go down just so far. Again, your bullet MUST be started straight. A separate turned 'loading starter' that fits snugly on the barrel OD and carries a short start rod will do this (see The Muzzleloading Caplock Rifle, Roberts)." Kurt
http://www.gboreloaded.com/forums/index.php/topic,216645.msg1099172255.html#msg1099172255

http://www.gboreloaded.com/forums/index.php/topic,217321.msg1099178455.html#msg1099178455

[bikerbeans]

Austin,
 
I have one 45-70 that I am in the process of converting to an MZ.  For a couple of months I have been using fired & reprimed (not resized) brass w/ Large Pistol Primers. Chamber the brass and close the action, then load like any other muzzle loader, loose powder only - no pellets.  With my gun you need a minimum of 85 grains, by volume, to ensure the bullet/sabot is fully in the rifling.  The gun is capable of 1 to 2 inch 100 yard groups with Harvestor 40/45 sabots & Harvestor 200 grain funnel points, using BH209 powder.   However, I don't think Mr. Game Warden would approve of this gun during the deer MZ season.
 
I just bought a brass chamber adapter that closely resembles the one that Kurt described.   After a couple of range sessions I will say that it has some draw backs.  Biggest problem is blowby.  I modified the primer pocket so I could "o" ring the 209 primer and this helps, however the blowby around the adapter is enough to interfere with the lockup of the gun after about 10 shots.  I chamfered and flared the mouth of the adapter to go for a tighter fit but didn't help much.  This adapter needs to be "o" ringed but I don't think the design will allow for that modification.  Also,  you will need to remove your ejector unless you want to go looking in the weeds for your adapter.  As far as being a legal muzzleloader that I am not sure of in my state.  This adapter has a wall thickness of about .025" and a thick head so a minimum powder charge to keep the bullet in the rifling is now about 60 grains.
 
I have pretty much concluded that if I want to have a reliable hunting 45 MZ with a 1:20 twist I am going to have to have a screw in breech plug installed.  I think you could probably make a slip fit "o" ring breech plug but the fact that when the plug is removed you can chamber a 45-70 cartridge might prove problematic with the authorities.
 
BB
 
 

[Austin from NC]

You think you could blue loctite it in during season and make it legal? What about taking a chamber cast and turning a false cartridge to length with o ring groove then drilling hole through center with 209 hole drilled in back or would flame have to travel too far.

       Austin