I’m wanting to load for a nitro-proofed 577 2-3/4” martini that’s slightly less than 9-1/4 lbs. I thought that I would start with something on the lighter side given the weight. I considered using a nitro-for-black load. Since this is a single, no regulation worries. Are there other recommendations people may have? I thought a load using 5744 may also be a good place to start. Any 5744 data that someone has used? I understand the 40% rule of 5744 for starters (if 40% is the start, what’s the upper end?). Thanks in advance.

I have been using N550 and N540 in my 577 NE 3 inch with filler, for reduced loads. It has a good low pressure curve I am told.

My 577 2.75 NFB load is a 525 grain cast paper patched bullet with 69.5 gr IMR 4198 and case filled with backer rod. Velocity 1775 FPS.may be all you want in that light gun.
Larry

A 700 grain .577 NE cast bullet kills buffalo right now at 1700 MV.

PS. My point being that I think any hard/solid .577 Bullet will be excellent at around 1700 MV on everything up to cape buffalo. I think that is close to the velocity that the old timers achieved. ( The few experts that I know of today, like to get above 2000fps with 600-650 grain bullets, and "hair on 'em" but I have found that a more moderate velocity still gives a good, sometimes sudden, one shot kill with a good shoulder shot.)

Also, I too use backer rod for filler and with this big calibre, expansion is not require so I go for penetration with a hard cast bullet or a solid.

Thanks guys. I may give cast a try. It has certainly worked well since the BPE version came out. I even found paper patched pure lead bullets ready to patch. May be fun for hogs or deer. Thanks again.

Knotch, You will be well set up for good hunting. And don't let anyone tell you that you bullet is going too slow. The trajectory issue not an issue at all. It's easy to learn your bullet drop out to, say, 200 yds. The handgunners do it all the time. Good hunting, Brian.

I built a single shot 577 Nitro 3” for slightly reduced loads on a break-open Mossberg SSI-One rifle. I shoots great using RL-15 powder. I proofed the build with two rounds at full 577 3” 750 grain load and have shot 650s at 2100fps from the shoulder. It have shot 650 grain hawk, woodleigh, and cast and obtained velocities with a buddy’s Labradar. My rifle weighs 11.8lbs unloaded. I would recommend using some of the 5744 load data generated by the B&M guys at the following link. They provide pressure data. I would recommend using 550-650 gr projectiles and keep velocity down around 1500 FPS. That rifle of yours would be murder with my standard load of 650gr/1950fps/5500fpe.

https://m.b-mriflesandcartridg...Nitro%2010162013.pdf

If you are in the US and you need help with cast bullets, send me a PM.

Thanks,

RC

Wildcatter, Good advice, as far as I am concerned. That is exactly what I did with a H&R 10ga, Handi Rifle single shot. And I got lots of help from Michael and Sam at B-M rifles & cartridges and Ed Hubel. I ended up with Peregrine 700 grain BushMaster bullets. and CEB 600 gr and 650 gr. bullets. And I killed a few cape buffalo with it. My rifle weighs 12.5 lbs and I use VV N450 powder. 1800 fps kills cape buffalo D.R.T. Brian

Here is some info on using Trail Boss and H4895 for reduced loads
https://www.hodgdonreloading.c...cks/low-recoil-loads

This is cut and pasted from another site abiout IMR 5744 nad reduced loads
Terry Wieland wrote an article titled “Against the Stream†in the HandLoading column of the January/February 2006 issue of Petersen’s RifleShooter. In his article Wieland discusses both IMR Trail Boss and Accurate Arms 5744. The Trail Boss discussion is mostly about black-powder-equivalent loads for the old cartridges used in cowboy action competitions.

The AA 5744 portion is about reduced loads. Wieland needed a reduced load to get some trigger time with his .500 Nitro Express before a Cape Buffalo hunt in Africa. You can’t go plinking with a rifle that shoots that kind of cartridge, but it’s important to be well practiced before a hunt for dangerous game.

The formula from a Western Powders ballistician for reduced loads is

1) Fill the case to the base of the bullet with AA 5744 and weigh the charge.
2) Multiply the charge weight by .4 to get a 40% load. So 100gr. x .4 = 40gr.
3) Tinker as necessary to find an accurate load.

Wieland used AA 5744 reduced loads for the .500 NE, .416 Rigby, .32 Special, and .22 K-Hornet, so it works across the spectrum of case capacities.

I have used all three powders with success in various Large Bore Rifles
Have fun

Zepher, Good info, Thanks!