Just what is this ".50 Spotter Round" they're talking about over at Biggerhammer? Looks like a shortened .50 BMG cartridge to me. What's it's purpose?

I don't know but You and I both need some!I have a few tracer rounds that a very,very cool to watch.I've heard of Spotter/Tracer rounds which I think trace to the target and then a small flash when it hits?Thus Spotter.If I'm correct I need some of those too!

M48A1 and M48A2 Spotter tracer rounds were originally developed to work with the 106mm recoiless rifle. a Coaxially mounted 50 caliber single shot barrel was mounted next to the 106mm barrel. this was done back before the days of fancy range finding weapon and laser sights.

 The problem was when you fire a 106mm rifle at a tank and miss. The tankers are goanna get mighty aggitated, angry, and fearful of that 'big boom' that barely missed them and they are goanna put some hurt on your position.

 The idea was to develope a little marker round that had similar ballistics to the slow 106mm low pressure round. It didnt need much powder, but needed a good hard trace with a nice flash and smoke mark to be visable in all kinds of conditions. Needeing less powder and to prevent regular 50 cal rounds from being used the case was made shorter, much shorter.

 Do not attempt to fire these 'short cases' in anything that wasnt already specifically made for this specific round. for those of us with full sized 50's, tons of ammo suppliers are selling them the same way that they are selling us our other talon ammo, by getting them loaded from components in bulk.

Since the marker round wouldn't need to be exposed to the rigors of  being fired at high velocity (only designed for velocities of 1750 fps) or be pushed very hard from gas pressures, the makers of the actual bullet made its copper jacket kind of thin, and packed it with a variety of pyrotechnics. It is longer than other 50 cal projectiles and weighs an estonishing 828 to 833 grains. According to Army 'TM 43-0001-27' these included tracer igniter compound (which looks white'ish when fired in darker conditions), and a binary tracer compound (which then turns to a yellow'ish color and finally a red). Thats why the tracer looks white, yellow, red when fired (similar to the paint mark on the tip). The center area of the round is around the canilure is the "slug" mild steel Im guessing just like ball ammo but this is simply a barrel shaped slug of metal that barely extnds beyond each side of the canilure. I suppose this is to give it some unexpended weight and to give the round some integrity against the rifling of the barrel. The M48A1 had a primer in the nose to ignite the incediary charge. Later the primer was deleted (M48A2), because testing showed that the round stored better, had better balistics, was more safe and more stable for handling, and could be packed with additional incendiary material when the primer was deleted. This was also done in early mods of the Mk211 raufoss rounds too. Why not our blue tip incendiary ammo has no primer and those were made for years.

When a 106mm recoiless rifle is fired properly there was an obvious techniques, fire the marker and based on where it hit, fix aim and pull the louder trigger.

www.watsonsweapons.com/ is selling these rounds along with many other suppliers. Watsons also sells the bullets alone. Remember! This round is only designed to fly at 1750 fps so dont over load or it could self destruct in front of your barrel or worse in your gun!

OK. Thanks for that explanation.

Seems Mark Serbu has done something with this round as well - something along the lines of a replacement barrel and brake in this shorter caliber that retro-fits the Ferret-50.

I wonder if it would be a worthwhile investment - just in case the ".50 BMG Ban" passes into law since this is not a ".50 BMG" round???

...OR IS IT???

Quoted: M48A1 and M48A2 Spotter tracer rounds were originally developed to work with the 106mm recoiless rifle. a Coaxially mounted 50 caliber single shot barrel was mounted next to the 106mm barrel. this was done back before the days of fancy range finding weapon and laser sights.  The problem was when you fire a 106mm rifle at a tank and miss. The tankers are goanna get mighty aggitated, angry, and fearful of that 'big boom' that barely missed them and they are goanna put some hurt on your position.  The idea was to develope a little marker round that had similar ballistics to the slow 106mm low pressure round. It didnt need much powder, but needed a good hard trace with a nice flash and smoke mark to be visable in all kinds of conditions. Needeing less powder and to prevent regular 50 cal rounds from being used the case was made shorter, much shorter.  Do not attempt to fire these 'short cases' in anything that wasnt already specifically made for this specific round. for those of us with full sized 50's, tons of ammo suppliers are selling them the same way that they are selling us our other talon ammo, by getting them loaded from components in bulk. Since the marker round wouldn't need to be exposed to the rigors of  being fired at high velocity (only designed for velocities of 1750 fps) or be pushed very hard from gas pressures, the makers of the actual bullet made its copper jacket kind of thin, and packed it with a variety of pyrotechnics. It is longer than other 50 cal projectiles and weighs an estonishing 828 to 833 grains. According to Army 'TM 43-0001-27' these included tracer igniter compound (which looks white'ish when fired in darker conditions), and a binary tracer compound (which then turns to a yellow'ish color and finally a red). Thats why the tracer looks white, yellow, red when fired (similar to the paint mark on the tip). The center area of the round is around the canilure is the "slug" mild steel Im guessing just like ball ammo but this is simply a barrel shaped slug of metal that barely extnds beyond each side of the canilure. I suppose this is to give it some unexpended weight and to give the round some integrity against the rifling of the barrel. The M48A1 had a primer in the nose to ignite the incediary charge. Later the primer was deleted (M48A2), because testing showed that the round stored better, had better balistics, was more safe and more stable for handling, and could be packed with additional incendiary material when the primer was deleted. This was also done in early mods of the Mk211 raufoss rounds too. Why not our blue tip incendiary ammo has no primer and those were made for years. When a 106mm recoiless rifle is fired properly there was an obvious techniques, fire the marker and based on where it hit, fix aim and pull the louder trigger. www.watsonsweapons.com/ is selling these rounds along with many other suppliers. Watsons also sells the bullets alone. Remember! This round is only designed to fly at 1750 fps so dont over load or it could self destruct in front of your barrel or worse in your gun!

This post gets an A+!

Does anyone commercially load this round with something other than "pyrotechnic" projos???

I found the designation is 12.7 x 77mm in stead of the 12.7 x 99mm of our 50 BMG. the two recoiless rifles used were M27 105mm and the M40 106mm. I guess there was some limited use by the navy in some form or another with thier artillery.

 I dont know if anyone else is loading them, but I think it would be interesting to see how hot regular projo's could be loaded in it. But one other doesnt need to be loaded hotter. For instance, I have no doubt considering the small powder charged used in the "SLAP" or 'sabot' round would be ideal, since the oversized case of the regular huge 50 BMG case hinders proper flame propogation from the primer causing erratic burn rates of the small powder charge depending on the angle the weapon is being discharged at. This is caused from the small amount of poweder either being close to or far away from the primer inside the casing.

 The SLAP has a small recoil and is not to be used with a muzzle brake to avoid getting it ripped off from the sudden separation of the Sabot inside the brake. Yet it is powerful enough to penitrate over 2" thick colled rolled homogenious armor steel plating at engagable distances (at over 4000 feet per second).

 The regular 50 BMG SLAP is actually shorter than regular 50 BMG rounds by virtue that the projectile package is shorter on the shell the way it is loaded. What this means is it would be very compact indeed when loaded on this "50 short" spotter marker shelll.

 Imagine what a field soldier with an AR15 that looks fairly normal (only slightly extended in the reciever area) and a slighly larger magazine.  it would look like that USAS-12 gauge, 24 shot full automatic shotgun or like the SPAS-15 semi Auto.

USAS-12


SPAS-15  




Imagine the kind of havoc a few guys armed with these could have on an enemy light armored brigade.

 it would also give the squad level, a way to deal with snipers even though the SLAP round lacks a little accuracy it could effectively be employed by the average foot soldier even with pop shots at great distances. Snipers would definitely have to rethink the type of cover they take. The SLAP projectile with its 30 caliper solid tungsten projectile form would not be in violation of the geneva when used against enemy soldiers.

Quoted: Quoted: M48A1 and M48A2 Spotter tracer rounds were originally developed to work with the 106mm recoiless rifle. a Coaxially mounted 50 caliber single shot barrel was mounted next to the 106mm barrel. this was done back before the days of fancy range finding weapon and laser sights.  The problem was when you fire a 106mm rifle at a tank and miss. The tankers are goanna get mighty aggitated, angry, and fearful of that 'big boom' that barely missed them and they are goanna put some hurt on your position.  The idea was to develope a little marker round that had similar ballistics to the slow 106mm low pressure round. It didnt need much powder, but needed a good hard trace with a nice flash and smoke mark to be visable in all kinds of conditions. Needeing less powder and to prevent regular 50 cal rounds from being used the case was made shorter, much shorter.  Do not attempt to fire these 'short cases' in anything that wasnt already specifically made for this specific round. for those of us with full sized 50's, tons of ammo suppliers are selling them the same way that they are selling us our other talon ammo, by getting them loaded from components in bulk. Since the marker round wouldn't need to be exposed to the rigors of  being fired at high velocity (only designed for velocities of 1750 fps) or be pushed very hard from gas pressures, the makers of the actual bullet made its copper jacket kind of thin, and packed it with a variety of pyrotechnics. It is longer than other 50 cal projectiles and weighs an estonishing 828 to 833 grains. According to Army 'TM 43-0001-27' these included tracer igniter compound (which looks white'ish when fired in darker conditions), and a binary tracer compound (which then turns to a yellow'ish color and finally a red). Thats why the tracer looks white, yellow, red when fired (similar to the paint mark on the tip). The center area of the round is around the canilure is the "slug" mild steel Im guessing just like ball ammo but this is simply a barrel shaped slug of metal that barely extnds beyond each side of the canilure. I suppose this is to give it some unexpended weight and to give the round some integrity against the rifling of the barrel. The M48A1 had a primer in the nose to ignite the incediary charge. Later the primer was deleted (M48A2), because testing showed that the round stored better, had better balistics, was more safe and more stable for handling, and could be packed with additional incendiary material when the primer was deleted. This was also done in early mods of the Mk211 raufoss rounds too. Why not our blue tip incendiary ammo has no primer and those were made for years. When a 106mm recoiless rifle is fired properly there was an obvious techniques, fire the marker and based on where it hit, fix aim and pull the louder trigger. www.watsonsweapons.com/ is selling these rounds along with many other suppliers. Watsons also sells the bullets alone. Remember! This round is only designed to fly at 1750 fps so dont over load or it could self destruct in front of your barrel or worse in your gun! This post gets an A+!

A-. Wouldn't "coaxial" mean that the center of the .50 bore was in the center of the 106mm bore?

Also, the spotter-tracer gun was not a single shot. I don't know what type mechanism it had, but know it did employ a magazine.

Quoted: A-. Wouldn't "coaxial" mean that the center of the .50 bore was in the center of the 106mm bore? Also, the spotter-tracer gun was not a single shot. I don't know what type mechanism it had, but know it did employ a magazine.

it may mean that in the literal form but not in the military nomenclature. The military likes to call any assisting gun in lesser or greater caliber used next to or traversing with (sometimes traversing independantly) as "coaxial". We see this often, A P-38's 20mm was considered coaxial to the 50 cals around it but it basically was near the center of them so it is a poor example. The commanders 7.62 machinegun on a M-1 abrams is considered a coaxial gun as well. I don't know why. As those of us have served know; its the "military way" that counts here. The military does it thier way regardless of whether it is correct or not. In this case. misuse of the name "coaxial"?

...cool pic - thanks!