The biggest problem is finding someone with the resources to perform a controlled experiment that provides repeatable results. That "repeatable" result is a blown up gun.
Firearm and component manufacturers have no incentive to prove that low charges of slow or fast powder reloaded ammunition blows up guns because neither will ever encourage using "out of recommended range" reloads in any gun and no powder manufacturer would ever want the public to know that their powder can cause a kaboom even without being an extreme overload.
Charles J. Sharp's "A RELOADING DEBACLE" is an excellent detailed first-person account of a kaboom describing what was likely done to cause it.
It's interesting that he doesn't state that the one variable that he changed from the prior 3 shots was first pointing the barrel straight down, then lifting it back up to shoot. Reading several other posts about low charge kabooms with slow powder really points out (to me) that piling the powder away from the primer causes a delayed burn usually preceded by the bullet being driven into the rifling from the primer alone.
If I were given a dozen free rifles and a good solid tree to tie it to, a cord to pull the trigger and a steel shield to stand behind, I bet I could repeatedly cause kabooms. With a low charge of powder with a burn rate between super slow pistol (2400, H110, W296) or maybe relatively fast rifle powder, If you tip the barrel down and get the powder away from the primer, you will have a higher chance of an "SEE or kaboom" than if the barrel were first tipped up before pulling the trigger. Each powder has it's own burn characteristic and maybe even slower rifle powders would do this if they can get to that ignition point with enough space in the case, but enough powder to get the pressure high enough to blow up the gun. I say that because sometimes powders are so slow or a bad primer is so weak that the powder does not completely "go off" and disassembly of the cartridge shows a mess of partly burned powder in a case.
My takeaway from all this is not to use slow pistol powders in reduced large case loads. Small charges of fast pistol powder do work reliably and safely. I've done the barrel tilting thing (both up and down) with Unique, Red Dot, Bullseye, Clays, Titewad. The gun held up fine and the MV's don't change by much. Fillers don't make much of a difference other than seeing bits of pillow fluff float around after each shot.
Firearm and component manufacturers have no incentive to prove that low charges of slow or fast powder reloaded ammunition blows up guns because neither will ever encourage using "out of recommended range" reloads in any gun and no powder manufacturer would ever want the public to know that their powder can cause a kaboom even without being an extreme overload.
Charles J. Sharp's "A RELOADING DEBACLE" is an excellent detailed first-person account of a kaboom describing what was likely done to cause it.
Examing the cases I was pleased to see my first three shots yielded three perfect cases. Just as I was set to fire my fourth round Jack hollered asking a question. Pointing the barrel straight down while releasing the hammer I turned to answer. I then raised my Contender and just knew that this time I was going to bust the pigeon.
Pulling the trigger my Contender exploded. Reeling and dazed by the violent explosion, I just stood there stupidly looking at what was left.
It's interesting that he doesn't state that the one variable that he changed from the prior 3 shots was first pointing the barrel straight down, then lifting it back up to shoot. Reading several other posts about low charge kabooms with slow powder really points out (to me) that piling the powder away from the primer causes a delayed burn usually preceded by the bullet being driven into the rifling from the primer alone.
If I were given a dozen free rifles and a good solid tree to tie it to, a cord to pull the trigger and a steel shield to stand behind, I bet I could repeatedly cause kabooms. With a low charge of powder with a burn rate between super slow pistol (2400, H110, W296) or maybe relatively fast rifle powder, If you tip the barrel down and get the powder away from the primer, you will have a higher chance of an "SEE or kaboom" than if the barrel were first tipped up before pulling the trigger. Each powder has it's own burn characteristic and maybe even slower rifle powders would do this if they can get to that ignition point with enough space in the case, but enough powder to get the pressure high enough to blow up the gun. I say that because sometimes powders are so slow or a bad primer is so weak that the powder does not completely "go off" and disassembly of the cartridge shows a mess of partly burned powder in a case.
My takeaway from all this is not to use slow pistol powders in reduced large case loads. Small charges of fast pistol powder do work reliably and safely. I've done the barrel tilting thing (both up and down) with Unique, Red Dot, Bullseye, Clays, Titewad. The gun held up fine and the MV's don't change by much. Fillers don't make much of a difference other than seeing bits of pillow fluff float around after each shot.