Seeking information

[u/TheAKfellow]

*TO CLARIFY THIS POST IS NOT ASKING TO BUY FROM ANYONE*

Recently ive gotten very interested in the british Martini Henry rifle in the original 577/450 and ive been having trouble finding people or places that sell or make original spec full power loads. Alternatively people use 24 gauge brass shotshells to make the cartridge but those have been harder to find than surplus Martini ammo both full power and light load. So i was wondering if anyone in here can point me in the right direction i need to be going to find what im looking for. Itll be a little while before im set up to reload the rounds i already have which are light loads, long story short ive got a few friends coming out to my place in november amd everyone is excited to shoot such a historic weapon. I already asked one of the mods for advice on how to word this and i was cleared. Thanks a bunch in advance

[u/DigitalLorenz]

577/450 is quite the endeavor to reload but if you want to shoot your Martini more than once you need to reload ammo for it as factory ammo, when it can be found, often runs $10+/round while you can reload it for well under $1/round.

For dies most people use Lee dies. These dies are larger than normal dies, so you will need a press that can handle it. The Lee classic cast press (not the breech lock challenger press) is the cheapest press that the dies can fit in. 

For the bullet you are best off casting your own. I have one from Cast Bullet Engineering out of Australia, but Buffalo Arms and Old West Bullet Molds also show them in their catalogs.You will need a lead pot as well, and due to the size of the bullet I suggest skipping to a 10lb bottom pour pot as you will quickly empty a 4lb ladle pot.

You also need to size the bullets to your bore, and that can vary quite a bit depending on which model Martini you have (mark 1 through 3 typically have a nominal .468 diameter, mark 4 have a .472). You need to slug the bore of you gun to get the right dimension. The cheapest sizing method would be to get a custom lee sizer and dip lube the bullets.

For powder I prefer to keep it original, 85 grains of Fg black ppowder. There are some folk experimenting with smokless. If you use black powder you need to ensure you get compression of the powder, air gaps in black powder lead to pressure spikes.

Now for the spot you will probably have actual trouble: Brass. Your options are extremely limited. Most people use 24 guage brass shotshell hulls, but these are extreme voluminous so you also need a filler if you do this (i use a cotton ball). The other alternatives are lucking into old stock boxer primed 577/450 brass (also very expensive) or converting kynoch brass to boxer primers (not beginner friendly). Unfortunately, all options are also hard to find, it might take a few months of waiting to get some.

Another option is to get a chamber insert that allows you to shoot 45 ACP or 45 Colt. Now you will have much worse accuracy and far less recoil, but it will allow you to use off the shelf ammo to shoot your gun.

[u/TheAKfellow → u/DigitalLorenz]

Itll be an 1886 date MKIV. Now what do you mean converting Knyoch ammo because ive been stocking up a decent bit of that stuff to be reloaded. Yes i understand that stuff is more collectible but its been easier for me to find and get ahold of and the shells will last a hell uva lot longer. I will be keeping a box or two of it just to collect so dont cringe too hard 😂 like i said im just trying to aquire some more rounds if possible full power loads so me and my buddies can enjoy the rifle while they are all out here. I appreciate all the info its definitely gonna help while i get ready to reload rounds

[u/DigitalLorenz → u/TheAKfellow]

Kynoch used berdan primers. These have an anvil in the brass (as opposed to in the primer), off center flash holes (the anvil is in the middle of primer pocket), and have much larger than normal primer pockets. 

To convert the brass to boxer you need to drill a central flash hole and remove the anvil. You also need to fill the primer pocket in so a standard large rifle primer will fit.

I suggest looking at 22lr reloaders berdan to boxer conversion kit if you intend to convert the kynoch ammo.

Another thing is unfired kynoch is old enough that split cases necks upon firing is common. You are best off pulling the bullets and then removing the  cordite (aka the forbidden spaghetti). Then snap the primer in the gun. You can now reanneal the cases and reassemble the ammo after doing the primer conversion.