ID’s wanted for US 30x173mm cartridges

Hello Everyone,

I recently added 3 more 30x173mm cartridges to go with the other 3 I had already, which I believe are all American. I am trying to ID what guns these went to and am confused if they are early GAU-8 with copper drive bands or GAU-9 rounds (or a mix of both). With the lack of percussion or electric primers, different drive bands and no others to compare with in my collection I cannot ID any of them exactly.

I will list them from left to right, #1-#6 with details, hopefully some members here can ID them.

#1: Definitely a GAU-9 dummy and is marked as such on the projectile, pictured for details and comparison.

#2: HEI projectile with dummy fuze, copper drive band and aluminum case made by IVI in 1974 (3 years prior to the GAU-8’s introduction). Percussion primer fitted.

#3: TP projectile (made by MM, unknown manufacturer to me) with copper drive band and an orange anodized aluminum case. Made by MMT (Martin Marietta Aluminum division?). Also made in 1974, no primer. Same crimp grooves as the HEI.

#4: TP projectile with aluminum nose, copper drive band, no markings. Crimped to an aluminum casing with no markings and no primer. Looks very similar to the previous 2.

#5: Heavy steel TP projectile with no markings or paint, possible sintered iron drive band and crimped to a steel casing with no headstamp and only marked “DUMMY” on the side. Possibly made by Amron?

#6: Heavy steel TP projectile with sintered iron drive band, no paint and no markings. Paired with an equally heavy green lacquered steel casing. No headstamp and no primer.

Please let me know if you have any questions or need any further details! Thank you in advance and hope you enjoy!


nice group. Sorry I cant help ID these. remeber whern a large number of inert rounds sdhowed up on surplus market years ago, Lived in St Louis area thren and Emerson was the subcontractor on the feed system for the weapon that went in the A10! or sdould I say around which the A10was built! will have to unpack the rounds I picked up back thern all inert vartous case finishes and projectiles but nothing exotic. think all were TP with vaying colors!

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After doing some searching I am fairly certain that #2, #3 and #4 are all related due to the identical crimping grooves and projectile design. I would guess they are either for the early GAU-8 prior to switching to plastic drive bands or for the US 30x173mm CPIC gun but I cannot find identical cartridges to compare. I have found similar examples of ammunition for both so the jury is still out on a concrete ID.

The last 2 on the far right are still un-identified.