Smokeless Loads for Martini-Henry .450/577 and Snider-Enfield .577 Calibers!?

[Metman2]

Here's what I said:

Perhaps for the sake of neophytes one might add that the total case capacity is given in grains of water as a benchmark for comparing different cases. 'Grains' in this instance means actual weight, which for water is readily converted into units of volume. (divide by ~15 to get c.c.'s) It is not the same as 'useable' volume which is less and which depends on the seating depth of the projectile.Because that can vary, a better benchmark standard for comparison is total case capacity.

 

[Andy]

Perhaps for the sake of neophytes one might add that the total case capacity is given in grains of water as a benchmark for comparing different cases. 'Grains' in this instance means actual weight, which for water is readily converted into units of volume. (divide by ~15 to get c.c.'s) It is not the same as 'useable' volume which is less and which depends on the seating depth of the projectile.Because that can vary, a better benchmark standard for comparison is total case capacity.

That's a good way to explain it - thanks.

I have found too that generally a cartridge with 60% more total case capacity (full to the top of the neck) will have greater than 60% more usable capacity (generally full to the bottom of the neck).

 

[woodchopper]

Found this:

.577-.450 Smokeless Load Data

From Handloader Magazine (Nov-Dec 1978) by Jim Jukes on this subject, and it gives the following data (I apologize for the formatting, but I lost the war with the rudimentary editor used here):


Powder Charge Bullet Weight Velocity Remarks

IMR-4759 27 400 1,172 Mild load
Blue Dot 27 400 1,422 Good load - Max
Unique 16 400 1,124 Light recoil
Green Dot 16 400 1,094 Nice-shooting
Red Dot 16 400 1,136 Nice-shooting
Herco 20 400 1,272 Efficient load
IMR-3031 45 400 1,424 Powder left in bore - wadding essential
Blue Dot 19 475 1,075 Nice load. Accurate
Blue Dot 22 475 1,220 Very uniform, with wadding
Blue Dot 25 475 1,374 Powerful, but OK pressure and very uniform velocity
IMR-4759 23 475 990 Very accurate, mild
IMR-4759 25 475 1,109 Very accurate, mild
2400 20 475 1,132 Wadding a great help
IMR-4756 20 475 1,082 Very accurate load
Herco 20 475 1,213 Good Ignition
IMR-4227 30 475 1,144 Wadding a must
IMR-3031 45 500 1,582 Plenty of recoil. Some powder kernels in bore
IMR-4064 50 500 1,529 Unreliable ignition. Wide velocity spreads
Reloder 7 37 500 1,416 Unreliable Ignition
IMR-4759 27 500 1,170 Good-shooting load

somewhere I have a slightly different list that includes some duplex loads.

I did a fair bit of research and work up of my load for the MH 577-450

I am using IMR4227, I tried several slower powders and found that they were not burning. I am also using magnum primers.

bullets I use a 405grn RNFPGC (round nosed flatpoint gas check) I think they were bullet barn and are lubed cast bullets (I need to find some more)

I think I started with 32grn and worked up to 42grn of powder with 2 sheets of cheap toilet paper for wadding. I settled on 38 grn as a sane load giving me a Mv around 1650fps.

 

[Andy]

The funny thing for me is that the only cartridges for which I liked H4227, were 351 WSL and 401 WSL. Now that I've gotten out of them, I doubt I'll ever use the last few ounces of it that I have.