Experimental heavy machine gun and autocannon cartridges

Thanks to Brian (BDgreen) showing the great photos of Amron ammunition, I thought about taking a photo of my few Amron cartridges I had. However I think it would be more interesting to see a more varied selection of experimental cartridges from 12.7 to 50mm. Descriptions are from left to right, and I will try my best to include the company / country of origin along with the cartridge type.

Pic #1: ARES .50 TARG, US .50BMG Type 10 SALVO, US .50BMG hypervelocity test, US .50BMG hypervelocity test (same project), US .60 aluminum case Ball, Belgian FN BRG-15 15.5x115mm TP-T

Pic#2: 3x South African 20x42 variants (2 TP 1 dummy), US 20x87mm caseless replica, US 20x125mm Davy Crockett Spotter, US 20x135mm TP (for T74 cannon) US .90 T4 TP, Soviet 23x105 HE, Amron 23x132mm, Soviet 23x260mm TP (I know, not experimental but too cool to leave out!)

Pic#3: Brunswick 25x155mm caseless TP, Amron 25x160, Colt 26x130mm TP, US 27x70b HE-dummy (?), US 27x142 TP, Amron 27.4x160 TP & APDS

Pic#3: US 30x86b TP, US 30x100 WECOM dummy, US 30x113b dummy, 30x126rb TP, 4x US 30x126b dummy (with T64E2 link), TP, steel case dummy & HEI, US 30x136rb HEI

Pic#4: AAI 30x160 half plastic, 3x Philip-Ford 30x165mm non-durable dummy, durable dummy and enamel case TP, 3x US 30x173mm GAU-9 dummy, aluminum case TP and steel case TP, Amron 30x185mm case

Pic#5: Rheinmetall 35x185, US 37x219sr dummy, US 40x180mm Super 40 dummy, 40mm Hughes Lockless display, Rheinmetall 50x330 Supershot APFSDS proof

Hope everyone enjoys! :grin:


Excellent collection !!!

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Simply fantastic! @pict#3: those are what I mean as an extreme rebated cases!
I need to have one :yum:

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Amazing selection, this is exactly my blood type :slightly_smiling_face:

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very nice rounds

the 30x173 steel case is not very common

i think the 15x115 has the wrong bullet ,never see a load with belted bullet ,only with “normal” bullet like .50 cal BMG

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30x173 steel cases are the today’s standard.
Aluminum is basically limited to GAU-8 and GAU-9 and the CIWS system the Dutch are (were?) using.
As the 30x173 is a NATO caliber (who has the STANAG on it?) now and standardized for ground use the cases observed are all steel.

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yes i know it but this case would be from 70’s to 80’s

i don’t talk about “modern” ones

Actually they existed back then as the case is an Oerlikon design. Aluminum it became in the US for airborne use.
Just that back in the 70s to 80s the caliber was not as popular in ground use as it is today.
When you will chase all 30x173 steel cases of those days you will find some. Means they are not such a big surprise.

I think you are correct, I think the bullet is for the shorter x106mm case type. This projectile has a plastic drive band, it’s been painted over blue with the rest of the projectile.

Until I can find the correct matching case / projectiles, it’s my only example for my collection.

ah ok
effectively i preferely get this combination than nothing

your 23x260 soviet is a real one ? if yes very desirable piece

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Nice bunch of very interesting rounds.
The Colt .50/.30 Salvo Squeeze Bore is not exactly experimental as it was used in Vietnam in the AC-47 gun ships.

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That’s very interesting! I did not know that, do you have any more information?

Haha exactly, it looks nice on the shelf until then! :grin:

And yes, 23x260 is a real TP cartridge, I believe I have a separate post on the IAA about it:

No I can’t find anything on the web in looking at the AC 47, or the AC 130 equipped with a Cal. 50/30 perhaps Lew or Mel or Keith P. or someone who knows more than I, & I could well be wrong for the 1st time (this morning).
But I may just have the wrong aircraft? But perhaps I have the wrong case type.

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I’m wondering how the cases in picture 4 with the teensie-weensie base actually work, is the bolt face rebated to fit, or otherwise how is the extreme tapered part of the case supported in the gun ?

It looks like an unneccesary complication both for the gun mechanism and for case fabrication.


Peter, they work in the way where a revolver drum is loaded from the front.

A side root in the design of the Mauser MG213.

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From the front ? … I can see that it might make the action shorter but does it eject the fired case to the front also ?

Is the rim there to drag the cartridge into the chamber, an injector rather than an extractor function … and if it is, how is the case extracted from the chamber ?

Questions, questions !


I know from the Soviet R-23 that they are using pneumatics (gas from the bore).
Means ramming the cartridge into the drum and also “blowing it out” + driving the drum and belt feed.
I am not expert enough for the US designs as I unfortunately do not have the gun manuals.

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.30/.50 SSB were on Navy boats. Riverine Warfare, Viet Nam. Mow down the jungle vegetation on the shoreline when the boats were ambushed

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Great, thanks Keith