Lead Alloy for Fast Twist Rate .45-70

[iplaywithnoshoes]

I'm expecting a .45-70 Barrel from Match Grade Machine this week for my TC Encore. It's a 27" tube with ladder sights I modded myself (hoping to build a poor man's BPCR/silhouette rifle). They essentially take Shilen blanks and machine them to fit the Encore frame. I feel like I am taking a risk however; the common twist rate for 300, 405 and 500gr loads is 1:20, with 1:18 being preferred for 500gr and higher. This barrel is in a 1:14 and I plan to shoot cast bullets in it.

Are there any alloys that work with this unusually fast twist without leading? Do I use a particular lube? Could the twist simply be too fast for practical alloys?

Any help is appreciated.

shoe

[runfiverun]

what's gonna happen?
your boolits are gonna go around faster?
not like your gonna push them 4,000 fps.

[Outpost75]

Years ago I used to shoot cast in a Ruger No.1 .458 Win. using black powder. It had a 14" twist also. I never used anything harder than wheelweights or backstop scrap, because that was the most plentiful and cheapest alloy I had. 1:25 tin/lead also shot well. This was pre SPG lube, so I used Confederate Army Lube [equal parts by melted volume of Goya manteca and beeswax].

[iplaywithnoshoes]

Years ago I used to shoot cast in a Ruger No.1 .458 Win. using black powder. It had a 14" twist also. I never used anything harder than wheelweights or backstop scrap, because that was the most plentiful and cheapest alloy I had. 1:25 tin/lead also shot well. This was pre SPG lube, so I used Confederate Army Lube [equal parts by melted volume of Goya manteca and beeswax].

What was accuracy like and what kind of bullet weights were your molds dropping?


what's gonna happen?
your boolits are gonna go around faster?
not like your gonna push them 4,000 fps.

I was worried about excessive lead deposits in the barrel due to faster-than-usual twist if the lead was too soft. And yes, I was thinking 500-550gr at around 1050-1200fps. I don't mind more spin, but i do mind lead scraping off...

[.22-10-45]

I cast the Ideal 245498 from range scrap and am shooting it in an original Winchester-Lee .236 (6mm) 1895 straight-pull sporting rifle with a 7 1/2" twist. No leading found.

[Outpost75]

I was using Hoch nose-pour 370-grain mold .462" diameter, 100 grs. of Goex 2Fg, card wad and Cream of Wheat to get compression. Expected grouping 4-6"" for ten shots at 200 yards or meters.

[Toymaker]

187031 187032 Pure up to 20:1 should do you fine. Initially you probably will get slivers of lead in the first 6 inches of the bore. The bullet is stripping trying to engage the rifling. They don't seem to build up and remove easily. I didn't try PC or jacketed bullets to stop the stripping but I did try LaserCast (BHN 35). It didn't work. But accuracy remained good. Eventually it wore in enough and it stopped.

[iplaywithnoshoes]

Perhaps I'm approaching this incorrectly. A lot of forum members cast for .308, 30-06 with 1-10 twists without reporting any severe leading. Since the heavier/longer/fatter (depending on the math you use) bullet has greater rotational inertia, lead is more likely to be stripped away tangentially going down the barrel. Could I be overthinking this and should just size the bullets correctly? Cleaning the lead slivers sounds labor intensive for something that can form after just 10 rounds.

shoe (new to casting)

[runfiverun]

some of us use 1-7 twist barrels at about the same speed they push their 1-10 twists.
fitment and launch is the key to good success.
don't get too worked up about having to push a brush down a barrel a few times.