I've often read PP allows us to push cast bullets at jacketed velocities... but another theory says the rotational rate of the rifling, when it causes the bullet to spin above 140,000 rpm causes shotgun like patterns.
So who's right?
Or are both right? Does a PP somehow allow us to get past the rpm problem?
I'll admit, I can't see how, but I'm no expert, and haven't tried it yet.
Well first off, there is no rpm problem, never has been. There is an alloy problem when one wants to go jacketed speeds in standard gun barrels and fails to get accuracy with a cast lead alloy
bullet. That rpm number someone yanked out of their rear only signifies the neighborhood of where things go from easy to a bit more difficult, that's it, that's all, nothing more.
Standard squeeze and grease cast bullets beat that rpm hypothesis bull excrement all the time. Some people just cannot get past cast bulletology 101 and then move on to cast bulletology 111, so they invent reasons/excuses for their failures instead of learning why they failed. The "big secret" to beating the rpm theory bs is nothing more than choosing the proper alloy for the requirements needed. THAT'S IT
What paper patching does is allow you to use an inferior alloy at higher speeds/pressures without going to a TOUGHER alloy. Notice I did not say softer/harder alloy in that sentence.
You can have a hard and weak alloy and you can have a relatively soft yet tough alloy. The trick is knowing when to use what, and how to make said alloy, that's basically all there is to it.