.45 Calibration Bullets from Frankford Arsenal

In another forum I frequent, a question was asked yesterday about .45 ACP “Calibration Bullets” and no one knew what they were. The subject came up from a member who had come into a full box of them dated 1945 from Frankford Arsenal which contained a quantity of 49 “calibration” bullets (I suppose because they would fit in a 7x7 square box). They were marked on the box label as having a diameter tolerance from 0.4498" to 0.4502" and look like FMJ GI Ball bullets. So what calibration purpose would these have been used for? Possibly for setting up loading or bullet forming equipment or performing ballistic testing? I did a forum search here, but didn’t find anything mentioned which was specific to the purpose of such bullets.

These were used as standards to compare with production.
found in Cal. .30 M-1906, 5.56 / .,223 & other U.S. case types.
This box has steel cased, primed cases headstamped “F A 45”.

Below is a picture of a 49-bullet box from Franford Arsenal. This particular box seems to be for standard cartridges, and is not marked with any specifications, date, or as “calibration components.” I only show it to give an idea of the shape of the box, and for general interest.

Beneath it, in the same photo, are two different and later boxes than the one Pete showed, for caliber component primed cases, again, just for interest although they certainly relate to the calibration component bullets.

The bullet box is sealed, and I don’t wish to open it in this case (usually I do with cartridge boxes), but I am sure they are 230 grain FMJ bullets. Just for fun, I put a strong magnet to the box, and found that the bullets must be GMCS (Gilding-Metal-clad steel jackets), as the contents were heavily magnetic.

The cases in the 1948 box are steel, and Headstamped F A 47. The primer is copper, and uncrimped.

The second box, dated 9 May 1951, have the same cases, steel with copper primer, but headstamp is F A 51.

John Moss

1 Like

This is a picture of the box of .45 calibration bullets, but is labeled differently from the one shown above. I still have no good idea as to exactly what was supposed to be calibrated with them or how.they were intended to be used. Obviously there was some reason that they needed to be exactly 0.450" +/- 0.0002" in diameter. As there are clearly also calibration cases, I’m wondering if the calibration bullets were intended to be loaded into calibration cases to make calibration cartridges? If so, then what were the calibration cartridges used for? I see that Ordnance drawing 6136799 specifies a .45 bullet diameter tolerance of 0.4495" to 0.4505", so the calibration bullet diameter tolerance is much tighter than of the typical .45 Ball production bullet (0.0004" vs 0.001").

1 Like

Hi Dennis
These were used as a standard to compare to / with production lots. These could be loaded / completed and then tested to compare with production lots, to see of production was up to standard. Or perhaps used in other tests.

Dennis - the label you show is different from the one I posted because, as I mentioned, I showed my box only to show the size format (square), and mentioned it was NOT a calibration components box, just ordinary bullets.

Great label you posted. I have the calibration cases with two different box labels, as shown below the “ordinary” bullet box, but I had not seen a bullet calibration components label before. Thanks for posting it.

I have other FA bullet boxes, but they don’t relate in any way to this subject, so did not shown them.

John Moss

I weighed 3 bullets from an opened box of Frankford Arsenal M1911 .45 Calibration bullets. I expected them to all be very, very close to 230 grains. I got the following weights:

228.5 grains
229.1 grains
230.7 grains

Just in three bullets that is a weight spread of 2.2 grains. That seems excessive to me for “calibration components.” I would not expect a much greater spread in bullet weights if weighing projectiles from ordinary issue service ball ammunition of the same caliber and bullet weight.

John Moss

Interesting, but maybe not too consequential if their purpose was more for dimensional than ballistic consistency. Have you miked their diameters?

Geeze, where do you guys find these gems? Here’s my only measly box… I wanna be like you guys when I grow up, seriously lol

I can’t believe how much I’ve learned since returning home, I wish my father was still alive so he could see how much I’ve learned this far, thanks to you all!

hfhubbard - don’t be discouraged. I have about 170 different US military boxes for the .45 auto cartridge, but then, I specialize in auto pistol ammunition. If I was a general collector on the average budget, even after 57 or so years of collecting, that number for one caliber and one country would be almost impossible, and in fact, in my view, near insanity, to accumulate, if similar numbers in all other cartridge categories were similar.

That Twin Cities box you show is a beautiful example of a standard, post WWII .45 M1911 cartridge box! The condition of it could hardly be better.

I should add, that I will save a box in any condition that I can get, if I don’t have it, and most boxes, if full, I empty down to one or two rounds to reduce weight and possible damage if the box is accidentally dropped while handling. I do not require full boxes or mint condition, although all of us would rather have a nice box than a rumpled one! I also will save a box that comes to me empty, if that is the only way I can get it. Boxes are more than just something nice (in our view, as cartridge collectors) to look at. They have varying degrees of good information as well, especially proper nomenclatures and spelling of the manufacturer, etc.

John Moss

Dennis - no, I did not, but should have. Have to get off this computer now, but will do that later, leaving it to the three specimens I weight just for continuity.


Henry the S sufix lot number from your box should indicate steel cases. What it the date ?
Yes nice minty box.

And what about the length of each bullet?

Not yet. I just got back from Dan Nolan’s funeral in San Diego (Miramar National Cemetery). I drove down Tuesday, went to funeral Wednesday, and came back today. Am a little tired at the moment (1,000 + miles of driving in three days), so might not get to it for a few days. I came back to 27 emails.

I will measure Diameter near the base of the three bullets and over-all bullet length of each of them.


1 Like

Badger Jack - Decided to get this done first. The measurements are below. These bullets were pulled at random from a previously-open box, but still appearing to be full.

The First figure is bullet diameter spread, from measuring the diameter in three different places on the same bullet. The second figure is overall bullet length:

Bullet 1 - 0.4485" to 0.4495" 0.6655" OABL
Bullet 2 - 0.4490" to 0.4990" 0.6665" OABL The bullet appears to be perfectly round.
Bullet 3 - 0.4490" to 0.4495" 0.6700" OABL

I am really not into this tech stuff to accurately analyze this type of measurments as to whether or not they are “good specs” or sloppy ones. I can only say that like with the bullet weights, I am not terribly impressed considering this a calibration-component projectiles. I would image that these, the cases and the primers are simply hand-picked out of large standard lots for their uniformity in all measurements, rather than actually manufactured specifically as calibration components. I could, of course, but totally incorrect as to that assumption. I only know that for their purpose, it seems to me that despite the tiny increments involved with these three bullets, they could have done better.
Again, may I am wrong because for their purposes, these filled the bill. I simply don’t know.

John Moss

1 Like

By the way, my comments are simply my own evaluation of the bullets. It has nothing to do with their interest, both the bullets and the box, for the Collector or student of ammunition. It is a great box.

I should have re-read Dennis K.'s analysis on this thread also. It seems from the measurements indicated on the box are where they should be, but on my electronic digital caliper, the three I measured do not seem to meet that measurement. They are within the tolerances by the amount of the difference in them, but all seem to be undersized, which I cannot explain.

There is no question about their originality to the box, however, and again, it is an interesting box and a great addition to any .45 box collection.

I wish I was more up on the technical points regarding items like this. I am much more into the historical aspects of cartridges than the analysis of such things as their measurements being suited to the intended use, and the like.

If anyone has any comments regarding the measurements I came up with from three original samples from a 1945 box, I would love to hear them. I am fairly confident that them measurements are right - that was the purpose of the measuring them at three different points on the bullet, but maybe I did not measure them at the position on the bullet that determined those shown on the box label.

John M

1 Like

Sorry for late reply guys. The box I showed is empty. I picked up a few rounds last month and it was given to me for free. As you guys already stated it is just a very minty box and I couldn’t bear it if it ended up in the trash bin just for being empty.

Pete, I opened the box and checked the flaps and I can’t see any dates or make out any cartouches so I have no idea the date. If I’m looking in the wrong place let me know. Yes, box is in great shape and am glad to have it!

Hi Henry
I was hoping for a dated headstamp on the steel cased rounds originally in it. but…

Pete - I can’t help with that exact lot number, but I have boxes for the following lots:

TW S 18065 Steel Case, T W 5 3
TW 18077 Brass Case, T W 5 3
TW S 18495 Steel Case, T W 5 6

The date spread for TW .45s is pretty short.

The above are for box specimens from boxes I collected for slight variations in the label (I don’t save them by every lot number) that I left specimens in for the information needed on them. All of these have silver-color primers (don’t know if nickel or zinc washed or what) and GMCS bullets.

Maybe someone else has lot numbers that can fill in some of the gaps, or a good list of TW lots numbers and what they appeared on. I am guessing 1954 or 1955 for the lot number S 18444 shown on this thread, but in truth, with that number, it could be any year from 1953 - 1956.

The three boxes are shown below. The box label for Lot S18065 has a stick-on top label. The box for Lot 18077 (brass case) does not, of course, have the preprinted “S” on the label and the label is printed directly onto the box top. The box label for Lot S18495 also is printed directly on the box top, and has the preprinted “S” with the rubber-stamped lot number.

There is also a tracer box and a couple of unimportant ball boxes differing only in one having the “S” rubber-stamped along with the number, and one with a little bit of print-spacing variation. I did not bother to take space up to picture these.

John Moss

1 Like

Thank you John