Sub-caliber cartridges

i was looking thru my box of boxes an found this one. it reads:
172 gr. 9 o boat-tail bullet
20 sub-caliber cartridges
caliber .30
sub-caliber cartridges
manufactured by frankfort arsenal
drawing B -6146 cartridge loy no.29
172 gr. 9 degree boat-tail bullet

top of the box reads:
loaded mar. 18, 1926 // loading machine 27 // loader sl 21 //gauger sb 39 // inspectors sb 37 18 // packers sb 36 ss 16

what do i have?? the box is sealed and wrapped in plastic and i dont reall want to open it. a hand written sticky says .30 ? 30-40 krag ??


Wouldn’t that be the standard M1925 Cal 30 Subcaliber cartridge (30-40 Krag)? Prior to standardization it used the BT Match bullet instead of the M1.

See IAA JOURNAL #408, page 30.

I guess Randy Hedeen hasn’t read this or he would answer. Send him a PM.


Hello, Khege…What you have is the Model 1925 Sub-Caliber cartridge box, exactly as Ray M. described. The cartridges within use a standard .30-40 Krag case, most likely with headstamp F A 26 . The cartridges in the box will have a ring crimped Monel Primer, which is a silvery color. (Monel is a metal alloy of approx. 70% nickel and 30% copper) (Some of these will be found with a primer cup made of steel, plated with Monel) The bullet is the National Match bullet that was being used at the time, 172 grain spitzer with a 9 degree boat-tail at the base. About 1924 or so, Frankford Arsenal had used up all of the 220 grain Cole bullets normally used for this cartridge, and so began loading bullets designed for the .30-06 cartridge in the Krag sub-caliber cartridges. Cartridges of this type were loaded by FA up to and including 1928. The cartridges were used for training and spotting purposes in artillery weapons, most commonly the 3 inch seacoast gun, thereby not having to use the much more expensive artillery rounds for practice. The sub-caliber cartridges were fired in a barrel and action installed within the barrel of the big gun, and the sub-caliber cartridge primer was struck by the firing pin of the big gun, necessitating the Monel primer, which would not be pierced by the relatively heavy blow of the firing pin of the artillery piece. The nomenclature on the box about Loader, Packer, etc., was pretty standard on FA boxes of the period…Randy

Randy - How did this sub-caliber system work? If the bullet has no tracer or explosive component to see either where it went or where it landed, what was the point? If I shoot on the range I use a paper target so I can see where the bullet went and how much I missed by. Did the Navy have massive paper targets to shoot at? I have seen that some other sub-caliber cartridges also have ball type loadings with tracers being an alternative.


Hi, Will…Predominantly, sub-caliber cartridges were used, back in the days of the Krag, for artillery piece practice firing, although somewhat for spotting, as bullet strike could be observed if conditions were right, such as a dusty environment. Once upon a time, I had a photo of the apparatus used within an artillery piece breech to fire the Krag cartridge, but cannot think where it is now. Some of the small artillery pieces, such as 37mm, used a composite wood and metal “cartridge” that contained a chamber and barrel within for the sub-caliber round, including .30 Army and .45-70. So, no, the Navy did not use massive paper targets, although, when stationed on a salvage tug, we pulled many a tow target for the REALLY big guns…

Bill Brophy’s Krag book shows a subcaliber unit reconstructed, as I think I recall, from a ruined original recovered from Bannerman’s Island. It resembled a stockless krag barreled action in a suitable fitting. JG

Re: the subcaliber devices: I believe that there wre two different styles of devices, which used separate types of ammunition.
(a) Brophy’s Krag book shows a sub caliber device which was inserted into the threads where the breech block normally closed. It apparently was fired by lanyard, The conventional Krag rifle bolt mechanism stuck out to the rear of the breech of the gun (as the breechblock could not close with the rifle and adaptor stuck in it). Conventional rifle ball ammunition could be used in these.
(b) I believe there was also (but have not seen an example) a subcaliber insert contructed of a conventional cartridge case for the large gun, with a .30-40 caiber barrel mounted (centered) in the axis of the case. The base of the case was exposed in these and would rest against the face of the closed breech, or perhaps had some sort of intermediate piece which transmitted the artillery firing pin strike to the rifle caliber cartridge primer. For this subcaliber use, the actual firing of the gun was done using the regular (artillery) firing pin, necessitating the monel or steel type primers instead of standard soft rifle primers.

Although it does not use a .30-40 Krag, I have a 90mm AAA and Tank Auxilliary Cartridge for Sub-Caliber practice and spotting that uses the .50 BAT round. It is a one piece brass cartridge and projectile made with about 1/2 in thick brass. The head screws off and there is a barrel that runs the length of the case and projectile.(was actually–mine has been de-milled by having the barrel cut off about 6 inches from the base). The base has a spring clip to hold the .50 BAT in place. The weight is the same as a loaded round of the 90mm. It was used for loading and firing practice. This would have been about the same as the 2nd type John S. described.