So has anyone studied the amount of bullet movement
results from the standard LR primer vs. the Magnum LR primer without any powder.?

I'd guess more if the projectile is fixed vs. breech seated. Assuming the cast bullet is at least .001 larger than groove.

RJ-35-40 wrote on Jan 20^th, 2023 at 10:44am:


Not sure what you're asking really? How much bullet movement, as in maybe firing a primed case with no powder to see how far it traveled down the bore?
I have done velocity tests on duplicate loads using standard primers vs. magnum primers to see what difference there was in velocity, or accuracy for my loads. I found small increases in velocity, but no discernable differences in accuracy. So I use up my magnum primers for my loads, but just keep them separate from my loads using standard primers.

In a pre-WW2 American Rifleman there was an article describing a crude test.  They fired primer-only loads in a rifle mounted vertically, with a dowel down the bore. They eyeballed how high the dowel was propelled, using a yardstick.  Just though you'd like to know that.    

Driving a lead bullet out isn't any different than slugging a bore. For a decade or more my SOP for slugging has been to fire an oversize plain lead bullet with primer only, or just a grain or two of Bullseye,  so that it stops in the bore.  Tapping it back out is trivial.   With a little fine tuning I can even control whether it stops in the throat or near the muzzle.

magnum primer were never about adding anything to the power of a load- at least not directly. What the purpose was is to provide a longer, heat-generating source of ignition so that the typically slow (harder to ignite) powders would burn consistently. If, for instance, you had a load with slow powder shooting quite well with standard priming, adding a mag primer is most likely to upset that good combination and be poorer performing- accuracy, velocity or both may suffer. My own shooting with magnum rifles. 7mm, .300 and ,375 for the most part have shown this since I am always getting great results with standard priming. Depending on yer own loads you may get the same results.

If one looks at the Rem. 91/2 primer flash and a non magnum primer one might tend to have a different different opinion. 
In German's testing he found that the smallest primer flash provided him with the most consistent powder burn / accuracy. 
He had also found that a primer such as the 91/2 would start a bullet moving prior to the powder achieving a full burn. 
This he found added to the inconsistent powder burning and effecting his accuracy.
But on the other hand for my own use I have found finding the right primer to use with a given powder and cartridge design does indeed make a very big difference in accuracy. 
Damn near impossible to do now due to the limited availability if any for any type of primers for the sole purpose of testing. 

Just to muddy the waters a bit can I bring in the cases with the smaller primer hole.
With the smaller flash hole the theory is that the primer flash will go through the powder further and quicker?
Of claims of better accuracy with cases like this, is it the case  that is giving it as like the 222 does.

Reply to Nero on flash hole size being a factor. In the 32/40 using BP and a RMC Everlast case with a small flash hole, the accuracy I get is much improved over using a case with a standard flash hole. But am using Rem 71/2 primers.

RJ-35-40 wrote on Jan 20^th, 2023 at 4:21pm:

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a parallel question was answered by an article of the MINIMUM load for a snub-nosed revolver (cast bullets).