H777 in milsurp black powder cartridges .43 Mauser .41 Swiss

[hpbear101]

I shoot a lot of smokeless in these old BP military cartridges as most of my molds produce bullets that don't hold enough grease for effective black powder shooting. I had watched a video on FortuneCookie45lc channel on using Hodgon 777 as an alternative powder during the current reloading component shortage. I thought I would share my results and I do think this powder will work for me in a variety of obsolete cartridges and a few current ones for that matter. I have tried Pyrodex in the past but find it to be very corrosive and a pain in the neck to deal with, I much prefer real black powder when I have a good mold to work with it.

I bought a couple pounds of H777 FFG to experiment with. I loaded some up in both .41 Swiss and .43 Mauser, as soon as I empty some of my 50-95 brass I am going to try it in the 76 Winchester. H777 is pretty dense so you get quite a few more loads per pound. In the .43 I used 80 grains by volume which came out to 56 grains by weight with a Accurate 45-370Y heeled bullet, in the .41 it was 50 grains by volume and 36.5 for a weighed charge with a Accurate 43-335B bullet (100% load density is called for). I used CCI large pistol magnum primers (as I have a surplus of them) both had a milk carton wad between the bullet and powder.

The .43 was fired through a 1871 Mauser (single shot), and the .41 was through a 1869/71 Vetterli carbine (cut down rifle). Distance was 50 yards, the .41 plate was 9 shots the first 2 of which were just under the plate with a 6 o'clock hold. Both shot pretty well and I will continue to work with them. By recoil the H777 rounds felt "hotter" than any of my smokeless rounds and per the Hogdon site H777 has about 15% more energy than BP. The H777 does leave fouling in the bore but the bullet lube seemed sufficient to deal with it. Clean up was pretty easy, hot water is recommended I used 10:1 Ballistol:water.


.41 Swiss


.43 Mauser

Tom

[358429]

That's really cool.

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[Gtek]

Have you played with a boolit with a grease cookie, or with a lubed felt with disc on top of powder column?

[hpbear101]

Have you played with a boolit with a grease cookie, or with a lubed felt with disc on top of powder column?

I have, it would work fine in a cartridge like the .43 Mauser, I don't think the neck on my version of the .41 Swiss is long enough for a lube cookie.

[Gobeyond]

I used 77 gr of t-7 in my 1871 and it almost came out of my hands. I think it might be too much pressure for that old metal.
18000 or more. I’d like to use mine up. It grouped ok for me. The gun handled it, but it’s just the unknown possibility that has so far stopped me. I was using a 400 gr from maple wood bullets with 9 bhn alloy about 30:1. Powerful bullet.

[hpbear101]

I used 77 gr of t-7 in my 1871 and it almost came out of my hands. I think it might be too much pressure for that old metal.
18000 or more. I’d like to use mine up. It grouped ok for me. The gun handled it, but it’s just the unknown possibility that has so far stopped me. I was using a 400 gr from maple wood bullets with 9 bhn alloy about 30:1. Powerful bullet.

Was that by weight or volume, and ffg or fffg? If you want to load it down you could always cut it back and fill the case with COW.

I shot a bunch up in my 71 carbine this week it kicks like a mule whether BP or 777. I also tried 1 round through the Chassepot and pretty certain that's too much for the Chassepot and I will stick to BP on that.

Hodgdon does have load data published for some cartridges, bottom of page 2.

https://hodgdon.com/wp-content/uploa...anual_2008.pdf

Tom

[Gtek]

I have these in collection and just to confirm, you said you were loading 80 grains by volume of T7? I think about a 70 grain ballpark of BP 2F is where that now 140ish year old single lug rifle was meant to play. 80 buy volume of T7 = 92 grains ballpark with 2F, please understand not preaching here but if that is indeed the case you may be pushing the envelope a weeeeee bit. The COW is some good advise, you can change sights, hard to change hands, cheeks, eyes and a really nice 71' is a G or more.

[Gobeyond]

Was that by weight or volume, and ffg or fffg? If you want to load it down you could always cut it back and fill the case with COW.

I shot a bunch up in my 71 carbine this week it kicks like a mule whether BP or 777. I also tried 1 round through the Chassepot and pretty certain that's too much for the Chassepot and I will stick to BP on that.

Hodgdon does have load data published for some cartridges, bottom of page 2.

https://hodgdon.com/wp-content/uploa...anual_2008.pdf

Tom

That was by volume of ffg If you are doing that I think I could get away with fffg of the black powder like in other threads. What’s your feeling about the t-7 in the 1871 and the 15% increase in pressure? I thought the vetterli was a weak action!

[hpbear101]

My thinking on the 15% for my use is modern cases don't seem to hold as much powder as the old balloon head cases of the BP era, and my 45-90 converted to 11mm are also little less in case capacity so I think its kind of a wash. The Vetterli isn't an overly strong action with rear locking lugs but for the same reasons I think I am fine with 77, I use mostly A2400 in the Vetterli's.