30-40 Krag Flash Powder Blanks


Hi, All…
Anybody have any idea who made and loaded this box…(Quantity 50)
Headstamp: REM-UMC 30 USA, Flat nickeled primer, red wad at case mouth…(and they got sloppy…red sealant runs down the case body on most of the cartridges…Box is dated April 4, 1941…

Stembridge ??..Although there must have been other blank makers…I am assuming this was for the motion picture industry…



Looks like Stembridge packaging. No idea if they did the loading in house or bought from elsewhere.


Questions on this for the movie blank experts out there:

Is “High Grade” refering to the powder composition or the “Flash Blanks” in general and is it aluminum used to make the flash?

If refering to the powder composition, is that in reference to the duration of the flash?

I think I recall reading that a feature of movie blanks where the muzzle flash is desired to be seen is that the flash has to last long enough to be picked up by at least one frame of the film. If the duration is too short, it could happen during the short time between frames and not be seen. Is that how it works?



I don’t know whether or not the “High Grade Flash” is another way of saying “Long Duration Flash,” which was on some movie blank boxes, but you have the concept correct, Dave. There were lots of different movie blanks for different purposes. Quarter loads, half loads, long duration blanks, etc. Often the sound of the shot is actually dubbed in later, even if the sound was audible at the time the blank was fired. In some instances, models of guns were made that when you pressed the trigger, had some sort of fuel ignited and leaving the muzzle, sort of a mini-flamethrower, but just enough to look like muzzle flash. They were silent, for filming in places like hospitals and the like, where it was simply out of the question to use “noise blanks” of any kind. The noise was dubbed in later. A great subject. Our friend from Australia, Doc Av, is the Forum’s expert on these, and in the past, has given us all some really expert views of the use of blank ammunition in the Cinema.

John Moss



Thank you for that information. I can recall seeing some older war movie where the muzzle flash looked like what you describe with the ignited fuel. Wing mounted machineguns firing from a plane (or part of one!) on a sound stage. Dubbing in the report makes a lot of sense as it never seems an audio recording can quite capture the sound of gunfire as heard by our ears. Gotta love that movie magic! Now if I can just figure out how they get those blank rounds to make a cool sounding ricochet so often…



Here is a Stembridge box…sealed so don’t know what the cartridges look like…Interesting that it states “30-40 BREN M.G.”



OK, Guys…I know…the box is sealed…and, I agree with John M. and Lew C. and others about the “value” of opening it to see what is inside…but…I always hoped I would find a nasty, “run over by a Kenworth truck” box that still had a few cartridges with it…to see what the cartridges look like…haven’t yet…and I’ve had the Stembridge box for years…SOOO…anyone have any comments on why the box states…30-40 BREN M.G…Did they “rechamber” a Bren MG for a movie…or what ???




Would think there would’ve been ample supply of .303 brass in 1953 to make chambering a BREN barrel to .30-40 far from practical for ammuniton reasons. On the other hand, rim size is not far off and the barrels come right off for easy access!

Very interesting…



Firstly, we do not know that the cases inside the box are .30-40 Krag. They may be .303 with a labeling error. Not likely, and I would bet they are .30-40, but we do not know that. Secondly, the actual measurements of the .30-40 Krag and .303 British are quite similar. The .303 is longer in OACL and in Head to bottom of the shoulder length, but both cartridges headspace on the rim, so this, of itself, would be no impediment to firing .30-40-cased blanks in a .303 chamber. Rim diameter of both rounds is similar (0.545" for .30-40, 0.540" for .303) and rim thickness is the same (0.064"). It looks to me like there would be no problem or danger in firing .30-40 blanks in a .303. It may be, and I don’t know this so it is pure conjecture, that in a Bren gun altered for full automatic fire with blanks, the .30-40 perhaps doesn’t jam as much due to its shorter head to shoulder and OACL. If that is. in fact true, than the availability of brass in the .303 caliber would not be an issue. I am not at all sure that in 1953, with the British involved in the Korean War (even if the truce had been completed), that there would be so much brass available anyway. That is a little before the huge amount of British rifles started to be imported into the USA, if my memory serves me. The .30-40 case may have been chosen simply on the question of availability of brass suitable to make a blank that would funtion in a Bren Gun.

Randy - you must be a mind leader. I almost chirped in on the “sealed box” issue in my answer to Dave, and didn’t as I figured I was beating a dead horse with that issue. : )

John Moss


OK OK…If anyone here has a prob with me gettin’ the razor blade out, SPEAK NOW !!!..Dang !!!..My hand is shaking…BUT…it is JUST a Stembridge box…not like a 100 YO Winchester…SOOO…maybe tomorrow, I’ll carefully cut into her and see what we have inside…and…seein’s how there are others interested, it’ll make it more “educational”…







Don’t feel any pressure to open your box. Just be sure to tell us what’s inside when you do…


Now that’s thinking in the box! In the world of blanks there must be a whole bunch of safe combinations you would never think of if using the case to launch a projectile. Great stuff! I can only imagine the efforts that go into making some guns work right with blanks just for a couple seconds of screen time.



Dave - Thanks! As long as you relaize that is all conjecture on my part. I have no documentation on it. In the case of belted and rimmed cartridges, though, I can say there are a lot of combinations where firing one caliber in a gun chambered for another, even with ball ammo, is not especially dangerous, because of how the cases headspace. I don’t recommend the practice except in a couple of instances, and probably wouldn’t do it myself in any instance, though. IAA MOST CERTAINLY DOES NOT RECOMMEND THE PRACTICE. THE ABOVE IS MY OPINION ONLY!

John Moss


Ok, Guys…I carefully slit the wrap around label on the Stembridge box…cartridges inside are definitely .30-40 Krag with headstamp PETERS .30 U.S.G…also, a mouth configuration and wad color (yellow) that I did not have in the singles collection. I wonder, also…did Stembridge have the capability to produce the cannelure on the case neck…or did they buy the cases with the cannelure , and then crimp the mouth after loading and insertion of the wad ? I’m betting on the latter scenario…



I got some cases once that came out of stembridge - a little assortment, including a couple fit for my auto pistol collection. They were all basic primed cases - no cannelures, crimps, etc. I think Stembridge probably had a pretty sophisticated setup for producing blanks. Don’t really know about the cannelure, but it wouldn’t surprise me if they were able to do that.

John Moss


Hi, All…I knocked the wad out of one of the blanks from the box first pictured in this topic. Dave E, asked about the composition of the powder. About 20 grains of what appears to be “sweepings” of black powder. This stuff ranges in size from FFg to dust. Some of it appears to be “regular” kernels of black powder, irregular, shiny, etc. The biggest pieces look like once upon a time they got wet, and are irregular conglomerates of powder and what looks like some sort of oxidation. No evidence of anything added, like aluminum, etc.




Bad enough you were nudged into opening the box…

I don’t know anything about the composition of blank flash powder but perhaps the odd conglomerated stuff is the flash component and the “oxidation” is finely divided metal?



Looking back at the box that started this discussion, that 1941 date is interesting. Is it possible this box had a military purpose and was not made for the movies?

Also, I would have expected the wads on the flash powder blanks from Randy’s sealed Stembridge box to have been red, not yellow. In my experience, the wads are the same color as the labels, the flash powder labeled loads being red and black powder labeled loads being yellow.

Usually, Stembridge was also kind enough to date their boxes, very often in straight forward fashion as the two boxes pictured on this thread illustrate, and occasionally with a less obvious three or four digit code, such as 260 (Feb 1960) or 1058 (Oct 1958).


I just googled “War Movies made in 1941” and found a list on Wikapedia of war films. In 1941 and 1942 there were a number of American-made war films that could have featured Bren guns.
One in 1942 was about Commando raids in Norway - a possible candidate. Just a thought.

John Moss


John M…The Stembridge box which states “FOR BREN M.G.” dates from 1953…The 1941 box does not contain any info on usage in a particular firearm…but was very likely made for a movie or movies made in that year or shortly thereafter…

Guy H… The wads from 1941 box are red…and, as you say, from 1953 box are yellow…but notice that in the photo, where the word “LOAD” is located, there is no info stamped there, like 1/2 or FULL …(relating back to the fact that, in some cases, wad color indicates blank “stength”)…Also…the Stembridge label is orange (y) colored…maybe yellow was close enough ???

I had thought about collecting these as a sideline…perhaps, if I find enough boxes, we can learn something by matching wad colors to label colors, etc…