Winchester .401 action proving box



I think this is a rarity being both 250 grain and action proving. Never have see one before. Were these live rounds or dummy rounds? If they were dummies, how are they different from the live rounds?



Those should be dummy cartridges but I’m not sure what would be the way they were distinguishable from regular loads. Perhaps a blackened case and a pierced primer?



Many of the early factory dummies were not altered by drilling holes etc, but I was once told that when the primer was placed it was just the cup with no anvil. The article then explained the anvil was iron so if there was a anvil it would be weakly magnetic if it was just the cup no attraction?? can this be true?


Dave and Vic,

I appreciate the replies. The few rounds that came in this box do not look different from any other Winchester brand .401 rounds. Of course they might be replacements from when the previous owner or owners consolidated boxes, etc. Thanks again.



Action Proving would seem to indicate proofing or proving it’s integrity to me, if so then these should perhaps be a proof round. If it stated Action Functioning then I might think inert rounds.

That said, I can’t say recall ever seeing this stamp on a Winchester box before.

Not seen iron anvils in Winchester production (ruling out experimental) products before either, inert rounds just used just a cup, or pierced/drilled the cup allowing the anvil to be seen but sometimes the anvil was tinned. Being of iron & not rust proofed (an extra production step or two) doesn’t make sense plus if you were all ready making brass anvils why go to the trouble of making iron anvils for inert rounds?

edited once to correct spelling


WRACo Vol 2 tells us that Functioning Dummy ctgs have blackened cases and dummy primers. I think that the box held proof rounds. Back in the 1930s or earlier, when Hercules made pressure data available, the standard load for the .401 generated almost 50,000 psi. What would an “action proving” ctg do that a regular ctg would not?

From experience, if you overload this case and fire it, the blowback breechblock returns so rapidly that the ejected case is caught before it clears the action port, jamming things. For those who play with such things, if you expand the neck of a 7.62x39 Russian case to 10 mm, you have a functioning .401 WSL.


While obviously of a more recent vintage, these images found on the internet show dummy cartridges identified as both “Action Proving” and “Action Proofing”.




Great Dave, guess that answers it.



So “Action Proving or Proofing” is newspeak for “Functioning Dummies”.


It would be Winchester or perhaps Olin usage only. Nothing generalized / new-speak about it.


Somewhere I have some Winchester (functioning cartridges? display cartridges?) 5.56mm/223, having empty primer pockets without flash holes. I got them direct from Winchester so they are the real thing.


As to the question about what action-proving dummies would
do that a regular round would not, the answer is that they allow
an individual gun owner, or more often a gunsmith, to check the
feeding function of repeating firearms and in some instances the
actual chambering of them, without the possibility of an accidental
discharge. Checking this function in a home or a shop is not
recommended. Accidental discharges do occur.

In what is probably a scarcer function of action-proving dummy rounds,
is there use by Firearms Safety instructors teaching general gun safety
or hunter safety courses to do the same thing; that is, instruct in the loading
of firearms or their feeding mechanisms, and the cycling of rounds from
the feeding mechanism to the chamber, with no chance of an AD.

John Moss


I remember a vist to the FN plant in the seventies where this sort of dummies was used to test Browning self-loading shotguns. The worker placed the muzzle on a rest on the floor. Pressing the butt forcefully downward, he cycled the action several times and the dummies were ejected as expected.
So it was cycling the action without actually shooting. The dummies had empty primer pockets,


Here is the cartridge that was in the box.




Good pictures, verifying that the rounds are dummies.
I think I have some similar dummies in early US Auto pistol
calibers, that is, looking like a loaded round except for one
or more small holes in the case. They are often tinned, also.

Early on, at least in the 20th Century, American dummy rounds
were with tinned case, and high-pressure proof loads were
with blackened cartridge cases. (Some dummies didn’t have
the tinning - probably depended on customer’s order and the
quantity made). Late on, they reversed that ID, with dummies
in blackened cases and proof loads in tinned ones, the latter often
with a red bullet, red bullet tip (looking almost like tracers) or a combination
of red bullet and all red case-head.

John Moss