Off the wall hypothesis, but these raggedy, oblong flans make me wonder if they were made by some sort of rolling machine or rolling pin before striking. @dougsmit , do you know? Does anyone know? Let's see your oblong coins! Post anything you feel is relevant.
Interesting theory! The shape does appear to have happened prior to striking, as you would think if made by striking it would emanate equally from the center. From my perspective, this phenomenon seems to appear less (or not at all) earlier on in the life of the antoninianus denomination, and then starts up around Gordian III—perhaps a new technology and technique was introduced? Here are some of my examples... And is this an example?? I personally don't think so... though oblong, it doesn't seem uniformly oblong, like the others. I'm uncertain.
I think they were flattened under a roller, indeed! Also looks like this was done in a limited period of time as for the various emperors featuring: Trebonianus Gallus up to Gallienus (at least amongst my coins).
I like that theory!! Antoniniani often have that rolled flan shape. I wonder if anything resembling rolling bars have been found in archaeological sites.
This one seems to fit the pattern. Otacilia Severa (wife of Philip I) AR Antoninianus, 246-248 AD, Rome Mint. Obv. Diademed and draped bust right, on crescent, M OTACIL SEVERA AVG/ Rev. Concordia seated left holding patera and double cornucopiae, CONCORDIA AVGG. RIC IV-3 125(c), RSC IV 4, Sear RCV III 9147 (ill. p. 173). 22x25 mm., 4.5 g.
Don't miss out the New Style of Athens! Athens New Style Tetradrachm 146/5 BC Obs : Athena Parthenos right in tri-form helmet 34 mm Thompson issue 18 Thompson catalogue:Obs Gaziantep 146?:Rev NEW? Rev : ΑΘΕ ethnic Owl standing on overturned panathenaic amphora below control mark ME 2 magistrates : XAPΙ ΗPA RF symbol : Cock with Palm All within a surrounding olive wreath
We can find oval coins in many times and places if we look at enough coins. Maximinus II - Rome Mark Antony Septimius Severus - 'Emesa' Kyzikos (thanks, PeteB) Of course, for some like this Persian siglos of Darius I, oval is normal.
Very interesting!... Philip II... AR Antoninianus 247-249AD(23mm, 4.29g, 1h). Rome, AD 247. Obverse..IMP PHILIPPUS AVG...Radiate, draped and cuirassed bust right. Reverse..PAX AETERNA...Pax standing left, holding olive branch and short sceptre. RIC IV 231c; RSC 23
Philip I, AD 244-249, AR Antoninianus, Antioch mint Obv: IMP M IVL PHILIPPVS AVG, radiate, draped and cuirassed bust right Rev: AEQVITAS AVGG Aequitas standing left, holding scales and cornucopiae
ELONGATED / ERRATIC FLANS Oops... RR AR Denarius ERROR BROCKAGE Q Fabius Labeo 124 BCE - ROMA X LABEO - Incuse and reverse of obverse Cr 273-1 Syd 532 Sear 148 BAMM! Samnium Aesernia AE21 263-240 BCE HN Italy 430 Vulcan Left - Biga Eh, 3rd Century, they were all messed up... RI Claudius II Gothicus 268-270 BI Ant Fortuna Etruria Populonia 3rd C BCE AR 20 As 8.1g Metus Blank HN 152 RR Plaetorius Cest 67 BC AR Den Helmtd Diety quiv cornuc S-C Eagle tbolt S 349 Cr 409-1 VF RImp Marc Antony & Octavian AR Quinarius 1.58g Military Mint Gaul 39BCE Concordia r Hands clasped caduceus Cr-529-4b Sear 1575 Syd-1195 LYCIA Dynast Perikles 380-360 BCE AR 1-3 Stater 20x14mm 2.8g Facing lion's scalp Triskeles BMC 157
Interesting, ants in the Decius to Claudius II range do often seem have this sort of shape. Here's a later one, Diocletian (Antioch mint - these early issues are noted in RIC to be poor quality):
