From left to right:
12.7 x 74 mm prototype, low shoulder (neck lenght 17.9 mm), unfinished mouth, unprimed, headstamp FLB 78 12,7 x 99;
12.7 x 74 mm prototype, low shoulder (neck lenght 17.6 mm), unfinished mouth, primed, headstamp FLB 78 12,7 x 99;
12.7 x 76 mm finished case (75.4 mm long), unprimed, headstamp FLB 12,7 x 76;
12.7 x 76 mm draw stage (84.4 mm long), headstamp FLB 12,7 x 76.
Fede, did they experiment with case types rather than just copying the known 12.7x76 case?
Alex, I don’t know why they made two different case profiles. This was a local development inspired in the well known .50 Spotter round but FLB wasn’t trying to duplicate the US M48A1 Spotter cartridge, or at least not in the beggining. No spotter bullet or flash tube for the primer was developed and it is reported that these cases were loaded with tracer bullets only.
No loaded specimen is know to exist, except for two different mock up dummies: one with a red painted ball bullet imitating a tracer and another with a flat tip bullet imitating the spotter (as I remember it was painted too and the colors were not red/yellow, but can’t remember which ones). Both were made from fired cases with a purple annulus and headstamped FLB 12,7x76.
By the way, these were not made for a coaxial spotting rifle like the M8C but for a subcaliber unit designed for the 105 mm Czekalski recoiless gun.
Fede, great info! Thanks a lot!
Though they did not intend to copy the US 12.7x76 they went very close for some reason.
Do you happen to know what spotting weapon Argentina intended to use with the 105mm?
The spotting “weapon” was a 105 mm recoilless shell fitted with a .50 caliber tube and firing system.
Oh, that sounds like a lengthy procedure for spotting, unloading, loading a life round and finally attacking the target.
To me it looks more like a subcaliber training device rather than a spotter system for combat then. That would also explain the simple tracers.
Alex, I call these “12.7 mm Spotter” because of the parent case, but as I said above, these were not made for a coaxial spotting rifle but for a subcaliber unit designed for the 105 mm Czekalski recoiless gun. In fact, the only spotter device ever adopted was a top mounted FAP (FALo) rifle loaded with a mix of spotter and tracer 7.62 x 51 rounds. It was briefly used and the spotter rounds are quite rare.
Here is the spotting rifle in unlocked position:
Ah, intreresting! So they tried to make a 12.7 spotter round rather than using the common and available 7.62mm?
Any details available on those 7.62 spotter rounds and their inner construction?
This is the 7.62 x 51 “Reglaje” (Spotter) round designated FMK 5 Mod. 0. Headstamp is F.M.“F.L.B.” - 7,62 - 71 - and the bullet weighs 9,020 g (139 gr), has a steel core and is filled with an undetermined “chemical substance”. No drawing or sectioned specimen is known.
Fede, thanks!