Plain Base cast bullet in 45-70 Part II

[Win 38-55]

Today I went back to the range to try a few more loads to see if I could get a little closer to a good load for these new plain base cast bullets I have. The rifle was the same Winchester 1886 45-70, which was shipped from the factory in 1904 and spent its life in the interior of Northern British Columbia (I wonder if it has an grizzlies in its century of history?). The rifle has a 26" octagon barrel, and I was resting the forearm on a block of wood with a folded up gunsock as padding. All shots were at 100 yards. Here's another photo of the old timer.

First target:
25 grains of IMR 4198, 1 sheet of 1-ply toilet paper (TP), 405 PB bullet .457", 1,279 fps/50/14 (the two numbers after the slashes are E.S. and S.D. respectively). Out of the 10 shots, 5 of them went into a cluster measuring 1 & 3/4", but the other 5 were all over the place. This load is not a keeper.

Second target:
25 grains of IMR 4198, 1 sheet of 1-ply TP, 405 PB bullet .457, 1,268 fps/30/12. This load was no great shakes either. Five shots. Stroke it off the list.

Third target:
28 grains of IMR 4198, 1 sheet of 1-ply TP, 405 PB bullet .458, 1,415 fps/22/10. This load was so bad I didn't bother to fire the last 5 shots. I'll pull the bullets and reload them.

Fourth target:
By now I figured I'd better try some of my gas check loads just to reassure myself that this gun could still shoot. This load was 29 grains of IMR 4198, 1/2 sheet of 1-ply TP, 405 GC bullet .457, 1,400 fps/54/18. The five shots grouped at 3 & 3/16" at 100 yards. I find it hard to get tighter groups than that due to the wide notch of the ladder sight. Here's the target:

Fifth target:
Now it was time to switch to Accurate 5744, which is faster than IMR 4198, so it would give a higher peak pressure for the same velocity, perhaps bumping up the bullet to seal off the bore a bit better. The load was 25 grains of 5744, 1 sheet of 1-ply TP, 405 PB .458, 1,285 fps/42/21. I had only loaded three rounds for this load and they formed a 2 & 3/4" group at 100 yards. This looks promising. More samples next time.

Sixth target:
28 grains of 5744, NO TP, 405 PB .457, 1,320 fps/19/7
This was one of Mike Venturino's loads, except he used a larger diameter bullet, which may be a significant factor here. Although I got a 4 & 3/4" five-shot group at 100 yards, this load is promising. Next time I'll use a .458 bullet, as load #5 did very well with that. Furthermore, I got this group with NO TP! TP may also tighten up the group .... don't know until you try.

Conclusions:
Scrap IMR 4198 for this bullet. 5744 looks very promising. I figure the higher peak pressure is bumping up the bullet better to seal off the bore, resulting in better accuracy. I might even take a look at 2400, but not before I play around a bit more with 5744 in the 25 to 28 grain range with the .458 bullet, with and without TP.

 

[wade]

very nice gun , looks like fun, i am useing a 45/70 guide gun with similiar loads for low power loads i use 10 grs unique pinch of dacron 350 gr d.g. bullet cuts 1 inch hole at 50 yds, 405 rcbs shoots about the same , i use the rcbs bullet with and without gas checks , the full power stuff gets the gas check, 56 grs 3031, goes 1850 , kicks a bit but shoots good,

 

[Salty]

Looking much better Win'. Thanks for posting all this. I like you get way more of a kick getting old rifles to shoot well with traditional tecniques I bet you'll have her doing as well as can be done with those sites real soon..

 

[stocker]

Win 38-55: What does your barrel slug at for diameter? I use .459-.460 in my ELR. I think a larger bullet may help you a lot. Groups are usually around 2" from my rifle which is as good as I can see the front sight. I don't use filler with 5744 at all although I do use PSB with other bulkier load powders. Tried a lot of fillers and finally decided PSB was worth the price. A pound goes a long way when you are only using 4 to 10 grains of PSB at a time depending on load/cartridge etc.

 

[Win 38-55]

The reason I tried a .457 bullet is because with the gas check bullets I found that .457 gave tighter groups than the .458 bullets did. That is not the case here. My bore slugs at .457.

 

[John Y Cannuck]

I'm also thinking that .457 is too small for a cast load. I am also quite surprised at the 4198's poor showing. I use H4198, but when I have used IMR, it has been fine.

 

[Win 38-55]

John, IMR 4198 seems to do very well with my Gas Check bullets. I suspect that these plain base bullets may be a little on the hard side and need a bit more peak pressure to expand them up to seal the bore. That is why I'm thinking of trying 2400 in addition to 5744.

 

[Sharps '63]

Varget and 5744 in 45-70

Win 38-55

I have good results with 36 grs 3031 and 350/405 grain lead bullets of various types in my Browning '86 45-70. I've taken two moose with that load, both one shot kills. This load is a BP equivalent load and will not stress even a Trapdoor.

I recently switched to the same weight of Varget and the rifle loves it. I upped the charge to 40 grs and will use that for hunting anything up to moose.

In my 50-70 Sharps I use 28 grs 5744 and couldn't be happier. I think the Sharps could digest a heavier charge of it. I've yet to try it in my 45-70s, but I will as I hear good things from friends about it.

Todd

 

[stocker]

Win 38-55: Your bore slugs the same as mine more or less a few ten thou. Mine was .4574 as near as I can tell. I have come to the conclusion that a gas check obturates better than a plain base bullet if the bullet is a bit small. I think (specify think) that the check despite being crimped probably seats very firmly on the bullet base on ignition and gains a bit of diameter back from the prior sizing. The end result is I try to go .002 oversize on everything for that riflle and it seems to work.

 

[BigUglyMan]

Have you measured the twist of the barrel? That might give you another variable to chase down. Maybe you need a bullet with a longer shank, or shorter?

 

[Win 38-55]

Stocker, I tend to think the same.

BigUgly, I've not measured the twist. That might be something to check if I can't find a good load, but this is only my second time out and I've already learned that this bullet likes faster powders, so I'm optimistic the next time out will be just about there.