Seeking mold advice

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Last Post 12 April 2022
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David R. posted this 11 April 2022

I have a new (to me) Henry Big Boy in .357 Magnum. I want a good bullet mold for it. I'm thinking 158 grain give or take a little. I have taken a chamber casting and I would like to send it to someone to make sure I get a mold that is the optimal size for my bore. I've been on a few websites and it seems that some folks are now out of business. I have a Saeco #358 back ordered, but who knows when it will come or if it will necessarily be the best size for my rifle. I will be doing mostly informal target shooting at 100 meters, but I'm curious about shooting lever gun silhouette with it also. I've always gotten excellent advice on this forum, so I'm eager to learn what folks have to say.

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David R. posted this 12 April 2022

I want to thank everyone for their responses. I just got off the phone with Buffalo Arms. I am sending my impression to them and they will be making me a 158 grain RNFP Hollow base mold. We canceled the order for the Saeco.

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David R. posted this 11 April 2022

I am early in my development with this rifle. First of all, I have struggled with sights. It came with a Skinner rear sight, but that shoots 6" high at 50 yards. I have a new front blade and some alternate apertures ordered. In the mean time I punched a pinhole in card stock and taped it on my glasses. I can see the original sight fairly well that way. I could beat on a 10" steel plate off hand at 50 yards all day. Fun, but not serious precision shooting. I made a chamber casting and it measures ever so slightly over .356 by my measurement. Candidly, I don't completely trust my measurements. Perhaps I'm fussing over this too much and a half thou here or there isn't a big deal. I have very little experience with this process.

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Aaron posted this 11 April 2022

I do. Here is the 38 SPL. The 357 is a Pietta SAA

With rifle in hand, I confidently go forth into the darkness.

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Aaron posted this 11 April 2022

I would suggest simply slugging the bore and determine the groove-to-groove diameter of the barrel. Size to .001" over that measurement. For example: if the barrel slugs out to .357 G2G, then plan to have your bullets fall from the mold at .358" with your alloy of choice like 20:1 or whatever you choose. For the 357 Mag, you may get more use out of Lyman #2 alloy and respectable velocities. You can use White's 50/50 for smokeless loads and SPG lube if you decide to play with Holy Black. The world is your oyster right now and you have a ton of options with this cartridge.

With rifle in hand, I confidently go forth into the darkness.

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David R. posted this 11 April 2022

I haven't thought much of shooting black powder in this gun. Do people shoot BP in .357s?

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Little Debbie posted this 11 April 2022

I’ve had good luck with the Lee 158-RF bullet in two Marlin 1894s. They feed well and are accurate past 100 yards. They work well in revolvers too. It’s one of the bullets that will feed in the Marlins in .38 Special cases too. The cost of a six cavity Lee is a plus too. I have a Saeco 180 gr RNFP I like better in the rifle, but not so much in .38 Special loading.

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David R. posted this 11 April 2022

This looks like what I have in mind. I was just on their site. I was looking at the 35-155P. I'm not sure what the difference are. I don't have strong opinions. I would just feel more confident if I sent them my chamber casting and they determine the exact diameter.

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Aaron posted this 11 April 2022

I agree with Eutectic. Tom at accurate makes wonderful molds. For your rifle I would favor the 36-155C for a variety of reasons. It has a substantial lube payload both for smokeless and black powder which you may use in future. Its rounded nose profile will feed well in just about anything - particularly lever action rifles. You can cast it in whatever alloy your wish but should specify for Tom the alloy you will be using the most. This bullet makes my lever action rifles run butter smooth.