Dual Diameter mould from BACO

[ian45662]

It is a beautiful thing. I am going to take the plunge and order a DD mould

[Distant Thunder]

Because the length should be determined by the RPM that the bullet will be shot at you need to figure in the twist rate of your barrel and the velocity at which your rifle(s) will launch the bullet. That velocity will be a product of the amount of powder you can get behind the bullet. That powder capacity will depend some on how deep you seat the bullet. With the 2-diameter design the bullet should seated so that the base band is up against the rifling leade angle, so your C.O.A.L. (cartridge overall length) is limited by the based length. You could seat deeper but not longer than the base length will allow.

Deeper seating may or may not work with a 2-diameter design. I plan to test that this summer. It should be ok, but perhaps not as good as seating out to the leade.

My experience is limited to the .45-2.1 and the .45-2.4 cases. My long range bullet is not a 2-D design but length still matters, it began at 1.460" long and that worked great in my .45-2.4 Shiloh with a 1 in 18 twist. When I switched to my 2.1 Hepburn, also a 1 in 18, I had to do two things to get the same excellent accuracy I now get with my Hepburn. That bullet is a straight bore diameter bullet and I had to increase the bullet diameter to fit the larger bore diameter of my Hepburn, from .450" patched diameter to .4505" patched diameter. I also had to shorten it to 1.440" long. Only after I did those two things did I get that bullet to the same level of accuracy in my Hepburn that it had give in my Shiloh. Those are small numbers and many will say they are not enough to affect performance, but I say they did. Those two changes gave me the consistent performance I now have, nothing else was changed when I went to the shorter case.

The fit is easy to understand. The length change is all about velocity and powder charge. In the 2.4" case I loaded 102 grains of 1 1/2 Swiss and I was getting just over 1400 fps so the 1.460 length was good. In my 2.1" case I load 83 grains of 1 1/2 Swiss and I get 1290 fps and the 1.440" length proved to be much better for holding up out to 1000 yards especially in the quartering head winds we often have at Lodi.

If you are selecting a bullet length for the .45-2.1 and will also shoot it in any of the longer .45s you may be best served by a bullet designed for the 2.1" case.

The whole length/twist/stability thing depends also on how far you to plan to shoot. A bullet that is on the long side for the velocity and twist may shoot well out to 300 yards or 600 yards, maybe even 800 yards, but to reach 1000 yards with good stability I have found that a bullet just a bit under the maximum length the twist will stabilize at a given velocity is superior in difficult conditions.

With paper patch bullets you have to get a few things right with the bullet design, fit and length, but after that it's really very simple.

[Orville]

When it comes to what your calling dual diameter bullet is nothing new, instead of the abrupt change from the larger diameter to the smaller diameter, if the change was lengthen so as not to be so visible you would basically have an original Sharps bullet. Been shooting them for years.

[jackrabbit]

Shooting them, and shooting them accurately are two very different things...

[beltfed]

The long tapered Sharps design will fit nicely in a classic Sharps chamber.
But I believe the Dual Diameter bullet will fit a GG chamber better than a long tapered Sharps design.
The major/base band diameter and length is designed to seat nicely into a given FF case and freebore if any.
The change in diameter in many of the DDEPP bullets was set at 3.5 degrees, so as to seat in the leade.( perhaps arbitrary)
Not that abrupt. ( It could be set at a different smaller angle such as 1.5 degrees per side, particularly if matching
the angle of the leade)
AND the longer, parallel patch to bore body of the DD will center itself nicely on the lands.
beltfed/arnie

[Orville]

The original Sharps bullets are not one long taper, any where from a 1/4 to 1/3 of the bullet is straight no taper. They shoot just as accurately. I’ve seen a very early Sharps mould for the 50 2 1/2 it was made with the abrupt change too, but for some reason they apparently didn’t like it never seen another in any caliber.

[Coltsmoke]

What is the standard or most of the leade angles in these BP rifles?

[Kurt]

Orville,

Here is an original Sharps bullet mould made by the Sharps Rifle Company and it has a slight taper full length, very slight .003".
It could have been from a tool grinding problem. Hard to say.

IMG_0205.JPG

[Coltsmoke]

I was looking at some of Dan's post back on the BPCR forum and he was shooting a DD PP bullet back then.

[jackrabbit]

The original Sharps bullets are not one long taper, any where from a 1/4 to 1/3 of the bullet is straight no taper. They shoot just as accurately. I’ve seen a very early Sharps mould for the 50 2 1/2 it was made with the abrupt change too, but for some reason they apparently didn’t like it never seen another in any caliber.

Let's see some pictures of some groups, Orville.

[bruce m]

orville,
good to see you still around.
bruce.

[bruce m]

there were sharps bullets and sharps bullets.
they seem to have had hunting types and long range target types.
and they seemed to change with time.
this based on pictures seen, and older writings, as such things are rare in the flesh here in the great land up over.
we should not compare the swaged hard later long range bullets with earlier/flat meplat possibly hunting ones.
bruce.

[martinibelgian]

Once had tapered bullet mould from Steve brooks. PP bullet, patched from groove to bore. Never could get that bullet to deliver consistent accuracy, it now has become a groove dia. Bullet mould...

[Orville]

Bruce you got it there were bullets and then there were bullets. Jackrabbit deleted photo bucket if you can’t take my word then that’s your loss

[jackrabbit]

Orville, you ever heard of Walter Mitty?

Just in case you hadn't, I looked it up for you:

The American Heritage Dictionary defines a Walter Mitty as "an ordinary often ineffectual person who indulges in fantastic daydreams of personal triumphs".