Dual Diameter Mold for Shiloh 50-70

[PhilRich]

I recently bought a Shiloh Business rifle in 50-70. The bore dia is .500 and the groove dia is .510 with 1-22 twist. The chamber is cut for grease groove bullets, The chamber appears to be the 45 degree type with no free bore. I have to seat the paper patch bullet I'm currently using quite deep and losing significant powder capacity (Accurate 50-525T).

I do not want a bullet that exceeds 550 grains. A dual diameter design would enable loading upward to 70 grains of powder. So far I'm not aware of a bullet mold that fits this goal. To keep the bullet weight down the length would probably not exceed 1.25 inches.

What would be the best bullet design when using a paper patch that adds .006 to the diameter, with an elliptical nose?

[PhilRich]

BACO JIM492500 looks like a good start for a ddpp design. I'd like advise on how this should be modified to a ddpp.

[Luke]

Are you sure about the bore diameter? My shiloh will lightly engrave a .498 bullet nose, I went to a slight taper for easy chambering when fouled. Mine is a grease groove, but you get the idea. The bullet you're using should work I would think.

[Bulseyetom]

Million dollar question, what is the inside diameter of the neck of a fired case? I would think that might be the patched diameter of the base of the ddpp bullet so as to allow a slip fit finger seating. Not an expert by any means but having asked dozens of questions about patched bullets in the last year or so I have learned that a chamber cast is a must and then start figuring out how long the base of the bullet needs to be and if possible, patch to the fired case. Remember, I am dumb but happy! Tom

[Bulseyetom]

Looking at the Accurate 50-525T, what does the bullet measure after patching at the 0.493 end of taper? Does it easily fit the bore at that point? That would give you a good idea of what the nose diameter should be on your new bullet. I have no experience with a tapered bullet at all but in this situation it should allow you to see at what diameter the nose snugly fits the bore. Also, Tom at Accurate will modify any bullet design to meet your specific need so you could modify 50-527P by changing the nose diameter, base diameter and base length to suit your rifle.

http://www.accuratemolds.com/img/bullet ... 527P-D.png

50-527P-D.png

[John Boy]

Standard 50-70 bullets for 2x cavity mold ...
Bullet mass/type Velocity Energy
425 gr (28 g) lead SP 1,448 ft/s (441 m/s) 1,979 ft⋅lbf (2,683 J)
550 gr (36 g) lead FN 1,375 ft/s (419 m/s) 2,310 ft⋅lbf (3,130 J)

[PhilRich]

Bulseyetom » Sat Mar 27, 2021 10:53 am

Looking at the Accurate 50-525T, what does the bullet measure after patching at the 0.493 end of taper? Does it easily fit the bore at that point? That would give you a good idea of what the nose diameter should be on your new bullet. I have no experience with a tapered bullet at all but in this situation it should allow you to see at what diameter the nose snugly fits the bore. Also, Tom at Accurate will modify any bullet design to meet your specific need so you could modify 50-527P by changing the nose diameter, base diameter and base length to suit your rifle.

http://www.accuratemolds.com/img/bullet ... 527P-D.png

In response to your question: The bullets I have molded in the 50-527T Accurate mold have a body diameter of .497 instead of the .494 shown on the drawing. The stated tolerance on the Accurate molds allow up to .002 tolerance. Because of this the bullet must be seated deeper than I want, losing powder capacity. This bullet actually weighs in at 550 grains.

I also have the 50-527P. Those bullets are also larger than the diagram shows. They will not work with the paper I wanted to use (Seth Cole 55W). I tried a 1 wrap patch with a 25 pound translucent tracing paper from Office Depot. This produced significant leading. Hence, I'm looking for a better designed BACO ddpp mold. The one wrap of the heavier paper produced a .500 dia for the bore riding section with snug fit.

For 45 ddpp I have a Brooks Mold that uses the same dimensions as the BACO JIM455546E. This bullet dimensions are spot on and is working great in both my 45-70 and 45-90. I'm asking for advise concerning the design for a 550 gr ddpp for the 50-70.

[Luke]

What kind of alloy are you using? I have several of Toms molds and they have all been dead on with the specified alloy. Your .497 is outside of the .002 tolerance quoted, you might want to email tom and ask about that. He'll help you out.