Some of my most accurate cast bullets are tumble lube. The .38 TL wadcutter, in particular, will shoot groups half as large as my K-38 gets from any commercial Match ammo I've tried in it. So I don't know where other's problems with them are coming from, but I don't have them.
The 16" twist standard in most .45 ACP chamberings is more than fast enough to stabilize anything in the size range of the Lee bullets. However, I note that you are firing just about right at the speed of sound. This is the so-called "sound barrier" and bullets experience a jump in drag coefficient due to shock wave formation at that velocity that causes potential stability issues. I've watched 168 grain .308 MatchKing bullets fired with a 10" twist fly beautifully until they drop too near the speed of sound and suddenly start to tumble (about 700 yards in .308 Win). It's caused by a dynamic instability resulting from the geometry of the bullet, and you could have a situation where the round nose sees some of that, while the truncated cone shape does not.
However, it's also possible the round nose is getting more cocked in the chamber and shaving lead at the front end of the chamber, distorting the bullet. For the pistol, try seating the bullets out as far as you can without introducing a feed and chambering problem. The more of the nose you can get into the throat, the less freedom it has to turn sideways.
In the Revolver you would probably benefit from checking all the usual suspects: Use a pure lead bullet or a sinker to slug the bore to look for a constriction where the barrel screws into the frame. Check the size of your chamber throats in the cylinder. These days a lot of 45 Colt revolvers still have throats cut for the old 0.454" bullets, but have modern 0.451" groove diameter barrels. They almost never shoot their best with lead bullets until the bullet diameter is within 0.001" of the throat diameter. It is typical of production revolvers that the throats are not all the same diameter, either. Reaming them to the same maximum size is a standard step to take in accurizing a revolver. Jacketed bullets mostly seem unaffected by these issues, but cast bullets are frequently upset badly by them.