I've tried various conical bullets over the past 30-plus years. Never found a design nearly as accurate as a proper-sized lead ball (.454 or .457 in the .44s and .380 in the .36s).
I've tried:
Lyman 37583 - Too long to fit under most rammers and hard to ram straight. Dismal accuracy. I think this bullet was originally meant as a short-range bullet for the .38/55 but is now mostly mentioned as a bullet for the .36 revolver.
Lee conical bullet --- Made to fit under rammer and has a heel to help it enter the chamber. I've tried both the .375 and .380 diameter versions in my .36 calibers. At 25 yards from a benchrest, they usually give 5 or 6-inch groups. From the same benchrest, the round ball will cluster six into 2 inches.
The .380 version of this bullet --- no longer offered by Lee --- will only fit in my Colt 2nd generation 1851 Navy's chambers. My Pietta-made Remington Navy and Armi San Marcos copy of the Colt 1862 pocket have chambers that are too small to allow its larger heel to enter.
Lee only makes the .375 diameter of its conical bullet now. If you absolutely must shoot a conical, it's probably the most consistently accurate I've found.
Buffalo Bullet --- Fits under the rammer easily. Lousy accuracy. Don't know why, but in my .36 calibers this bullet was producing groups (or patterns) or 12 inches or more at 25 yards from a benchrest.
Oddly enough, it began to leave a ring of lead at the forcing cone of my Colt 2nd generation when I used the Buffalo bullet. Didn't do it on my two other 36s. Have no idea why. This is the only projectile this revolver has ever leaded with, except the time I cast some balls of wheelweights instead of pure lead, out of curiosity. The harder alloy left leading in the bore, but no ring of lead at the forcing cone. Weird.
Dixie Gun Works --- Duplicate of the conical bullet issued with the 1851 Navy in the Civil War. Base not cut fla. Sprue is nipped off with pliers leaving a slight projection on the base.
This projection doesn't seem to affect the bullet's stability. All holes on the paper target are round and show no evidence of yawing.
Accuracy was typically 5 or 6 inches at 25 yards from a benchrest. Ho-hum. Often, a flier opened the group to 10 inches or more. Interesting historically, but not interesting accuristically (I know it's not a word, but sounds good .. heh).
And I'm not so sure that the conical bullets are more powerful than a lead ball, because of their greater weight. To load a conical, you have to reduce the powder charge to make room for the longer conical bullet.
For example, I regularly shoot 24 grains of Goex FFFG black powder in my 1851 Navy, with greased felt wad between powder and ball.
This gives me about 1,000 feet per second from the Navy's 7-1/2 barrel.
If I use a conical, I usually forsake the greased felt wad and use 18 to 20 grains of powder. I get about 800 to 850 fps, depending on the conical and how much powder has to be sacrificed to make it fit.
I recently picked up a 6-cavity bullet mould on Ebay that casts a short, heeled conical bullet for the .36 caliber. Not one mark on the mould or wooden handles to indicate who made it. Wonderful craftsmanship, though.
Probably made in the 40s or 50s, possibly as late as the early 70s. Hope to cast some conical bullets with it and try it out. It may hold promise. Bullet almost looks like a round ball with a heel. Very short nose on it.
Preliminary measurements of the cavities with my calipers indicate the heel is about .373 diameter and the ball is about .380. Should be a good fit. Of course, a real bullet will be smaller than these rough measurements because of the lead shrinking when cooling in the mold.
Lead balls are easier to buy or make, more accurate, easier to load, more accurate and --- if you want to shoot at a little extra range --- have a higher velocity. Hard to beat these good points.