In hand guns, softer is generally better than harder, right up to the point where big, nasty, heavy beasts need deep holes poked in them, at which point copper and brands solids probably become a better choice than hard lead.
Rifles are a bit different. As velocities get up above 1800 fps, bullet elasticity becomes a negative due to nose deformation, but there are ways to address that beyond just making bullets harder.
Yes and no DocRock,
I've already showed this 30cal rifle bullet.
It's an excellent design for hv in rifles with high pressure loads. Long body and short strong nose with minimal/shallow lube grooves. With the 14bhn alloy that I use (91/4.5/4.5) it failed in the 137,000+rpm range. This bullet I could cast with a harder alloy getting it into the 2800fps range. When you start getting into this territory you better bring your A-game. Careful casting and extreme culling along with excessive care in sizing and putting on gas checks all will play huge roles in performance/accuracy.
I made that 14bhn alloy for the more "common" cast rifle bullets out there/in use today. This is more along the lines of what common cast rifle bullets look like/are designed.
It has a long bore riding nose (.300" in diameter) that ends at the wiper groove. The wiper groove is the is that groove just in front of the top drive band. It's a design from an era long gone where lubes flat out sucked and left a lot of crud in the bore. The "wiper" groove gave the crud somewhere to go. But it is also a weak point in the bullet design. The large grease groove is also another weak point but was necessary for the older lubes. I've showed this target before, typical groups/results from those bullets pictured above. They are cast from the same 2-cavity mold. A cramer 2-cavity with 1 cavity a sp and the other a hp. This type of mold is excellent for head to head testing.
Most people look at that target and say big deal. The reality of it is that's a 186gr sp/180gr hp bullet being shot out of a 308w doing 2450+fps. When I hit the loud button that long bore riding nose that's sitting in the leade of the throat starts forward into the lands and starts twisting. The back of the bullet is going forward and expanding from the pressure of the load at the same time. The back of the bullet expands sealing/grabbing the ball throat (you should always size your cast bullet to the size of the ball throat for this reason). Now the back 1/2 of the bullet is being pushed strait forward expanding /sealing/grabbing the ball throat then the throat and lead of the chamber. The front of the bullet is still locked into the lands and twisting. This is why the wiper groove is a weak point as is the skinny shaft of the lube groove. Rotational torque affects those area's and you need an alloy that has elasticity to have is survive this type torque's/pressures everted on the bullet. The bad of that bullet has to go a long way before the bullet can stabilize having equal pressure on it the whole length of it's body. It has to travel past the ball throat that the length of the throat to get to stability in the bbl
In that target above you will see I used reloader 19, look up 308w data for reloader 19. You won't find much there, I used it because it's a slow burning powder that has a soft push for a short start pressure. I typically use H335 for that lee bullet in the top picture because it can withstand the rotational torques better. The trade off is nose slump. The cramer sp bullet starts to fail in the 2400fps range while the sp hp bullet can go up to 2500fps+.
So yes the nose does slum/fail but it's way beyond 1800fps. Too soft of an alloy and I got skidding, the nose couldn't take the rotational torque while the back of the bullet was expanding/grabbing/locking into the freebore and throat. To hard of an alloy and the wiper groove and skinny shaft of the lube grooves failed.
1800fps is child's play with cast bullets in rifles or pistols. 2000fps and it's starts to get tricky. 2400fps and up you better start pairing your bullet designs with an alloy that's elastic enough to mask the flaws in the bullets design for the extreme pressure/torques your trying to apply to it.
2 different bullets, bullet designs. The cramer needs an elastic alloy the lee could use strait mono-type. Smarter people then me figured this out decades ago. Eagan molds/designs are an excellent place to study/learn about bullet design. I have 5 of them along with a 30T tapered non- lubing die that fits lyman sizers to uniform the noses of conventional bullet designs. It's tapered .300/.301/.302.
Why Eagan molds??? Because they have a common theme, blunt noses and shallow lube grove/grooves. The deeped lube grooved 30cal has a .26" shaft and the lube groove is round, typical are .28". Eagan molds were designed to use strait linotype. One of Eagan's stronger designs
His bullets were designed for extreme accuracy in the +/- 1800fps range. Cast them out of linotype and bad things start to happen at 2000fps depending on the bullet design.
Anyway a bullets elasticity is a double edged sword, You need it to get a poor bullet design to go fast but then nose slump starts to become an issue at those higher velocities. At the end of the day using 1 alloy is like having a jack of all trades/master of none. But on the other hand 2400fps+ from 186gr bullet that's poorly designed or 2600fps+ for a good bullet design isn't too bad for the same alloy.
Perhaps you can post some pictures of what your testing with your cast rifle/pistol bullets. I'm always trying to learn more and I'm sure others would be interested also.
