I went to the gunshow last night and was talking to someone about this option and it sounded kind of interesting.  Any thoughts?

I have shot a 50BMG tracer round through a Barrett. Is there a specific weapon made to shoot tracers?

MT

Mark Serbu will build a BFG in S/T (I think) and so will Dave of Spider Firearms (Ferret50). All you have to do is have the barrel made and then put on the rifle of your choice.

Quoted: I went to the gunshow last night and was talking to someone about this option and it sounded kind of interesting.  Any thoughts?

Lack of affordable ammo.....loaded 50 bmg ammo with the same projectile being readily available......Blech.

Huh?  Tracers don't light up until it's a down range well clear of the barrel.  Maybe they have new tracers that light up in the barrel?  

No need for a different barrel, now if your rifle is chambered for Match ammo and you shoot milsurp ammo off the delinker.

You need to make sure that the round is configured for your chamber, do not believe for one minute that you need a different barrel just because you are shooting tracers.

I think a lot of folks here are confussing S/T with normal 50bmg rounds. The Spotter/Tracer is a different animal than the 50bmg being conciderably shorter and firing at much lower velocities. Yes, you do find the S/T projo reloaded in 50bmg brass but it was never delivered that way to the military.

The S/T does light almost right out of the barrel. Velocities are loaded down around 1700 fps to keep the round from detonating in the barrel. Very fun round.

www.gibrass.com sells S/T brass but when it is all gone it will be pretty hard to find so twenty years from now it might be hard to feed a rifle chambered for it.

Yep.  S/T is not .50 BMG.

Here's a good link to look at Spotter-Tracer also gives you a little warning if you plan on reloading them in a full size .50 BMG case.

Information from here
50 Caliber M8 API
The M8 API (armor piercing incendiary) was put into service in 1943 to replace the M1 Incendiary, and is still in service today. The M8 is built nearly identical to the M2 Armor Piercing except the M8 has 12 grains of incendiary mix (IM#11) in the nose instead of a lead filler, and a lead caulking disc in the base acting as a seal. Having the same hardened steel core as the M2, the M8 matches the armor piercing capability of the M2 with the added  advantage of incendiary effect. While it has considerably less incendiary mix than the M1, the performance of the M8 was greatly superior to the M1 because of it's ability to penetrate the target and ignite the material inside rather than just flash on the surface like the M1 often did, making for a greater first shot effect.  Bullet weight is about 649 grains, and identified by silver tip paint.

These M8 bullets have been pulled from US GI W.W.II dated ammunition on the "old style" bullet pullers. This machine splits the case neck and then gently removes the projectile. As a result of this operation, there is 1 small line on the projectile from a point just slightly ahead of the cannelure down to the beginning of the boattail, leaving only a negligible mark sticking out of a loaded case. These projectiles have all been run through a set of draw dies to insure proper diameter, and eliminate the high spot caused by the split line.

Pyrotechnic performance of these projectiles is only slightly less than the M1 Incendiary. The flash varies exponentially with the amount of fuel, so while the M1 contains 3 times the incendiary mix of the M8, the flash is only about 30% larger. These M8 are also safer ( we have fired 20,000 plus rounds and not yet had a muzzle flash,) but they are less sensitive. When shooting through steel drums, they flash on the second surface creating a flash inside the drum. Similarly, when shooting vehicles, the projectile generally penetrates the skin and detonates inside on another sheet metal surface. High speed photos show the tip breaking off with the first penetration, exposing the incendiary mix which then detonates on the second impact. Plywood targets are merely penetrated with no flash. They will flash on a dirt backstop, but unless they strike a rock the projectile will more than likely penetrate about 6" into the surface before flashing, making only a small visible flash.

From the Marine Corps Ammo information center
M8
Cartridge, 50 Caliber. Armor Piercing Incendiary (API). Identified by gray bullet tip.

U.S. Designation: M8

Synonyms: M8

Interoperable: Machine Guns, .50 Caliber—M2, M85, and other compatible systems.

NSN
1305000286603 (4 API/API-T Linked)
The ammunition can be used in all standard 12,7 mm (.50 cal) weapons like Browning M2 and M3, M3P, sniper rifles similar to Barrett M82A1 and can also be with changed cartridge case used in 12,7 x 107 weapons.

Standard .50-caliber ammunition types used in the M2 machine gun are the M33 ball, M17 tracer, M8 armor-piercing incendiary (API) and the M20 API tracer. Within the past 10 years, new rounds have been type-classified by the Army: the M903 sabot light armor penetrator (SLAP), the M962 SLAP tracer and the Mk211 multipurpose.

Quoted: Information from here 50 Caliber M8 API The M8 API (armor piercing incendiary) was put into service in 1943 to replace the M1 Incendiary, and is still in service today. The M8 is built nearly identical to the M2 Armor Piercing except the M8 has 12 grains of incendiary mix (IM#11) in the nose instead of a lead filler, and a lead caulking disc in the base acting as a seal. Having the same hardened steel core as the M2, the M8 matches the armor piercing capability of the M2 with the added  advantage of incendiary effect. While it has considerably less incendiary mix than the M1, the performance of the M8 was greatly superior to the M1 because of it's ability to penetrate the target and ignite the material inside rather than just flash on the surface like the M1 often did, making for a greater first shot effect.  Bullet weight is about 649 grains, and identified by silver tip paint. These M8 bullets have been pulled from US GI W.W.II dated ammunition on the "old style" bullet pullers. This machine splits the case neck and then gently removes the projectile. As a result of this operation, there is 1 small line on the projectile from a point just slightly ahead of the cannelure down to the beginning of the boattail, leaving only a negligible mark sticking out of a loaded case. These projectiles have all been run through a set of draw dies to insure proper diameter, and eliminate the high spot caused by the split line. Pyrotechnic performance of these projectiles is only slightly less than the M1 Incendiary. The flash varies exponentially with the amount of fuel, so while the M1 contains 3 times the incendiary mix of the M8, the flash is only about 30% larger. These M8 are also safer ( we have fired 20,000 plus rounds and not yet had a muzzle flash,) but they are less sensitive. When shooting through steel drums, they flash on the second surface creating a flash inside the drum. Similarly, when shooting vehicles, the projectile generally penetrates the skin and detonates inside on another sheet metal surface. High speed photos show the tip breaking off with the first penetration, exposing the incendiary mix which then detonates on the second impact. Plywood targets are merely penetrated with no flash. They will flash on a dirt backstop, but unless they strike a rock the projectile will more than likely penetrate about 6" into the surface before flashing, making only a small visible flash. From the Marine Corps Ammo information center M8 Cartridge, 50 Caliber. Armor Piercing Incendiary (API). Identified by gray bullet tip. U.S. Designation: M8 Synonyms: M8 Interoperable: Machine Guns, .50 Caliber—M2, M85, and other compatible systems. NSN 1305000286603 (4 API/API-T Linked) The ammunition can be used in all standard 12,7 mm (.50 cal) weapons like Browning M2 and M3, M3P, sniper rifles similar to Barrett M82A1 and can also be with changed cartridge case used in 12,7 x 107 weapons. Standard .50-caliber ammunition types used in the M2 machine gun are the M33 ball, M17 tracer, M8 armor-piercing incendiary (API) and the M20 API tracer. Within the past 10 years, new rounds have been type-classified by the Army: the M903 sabot light armor penetrator (SLAP), the M962 SLAP tracer and the Mk211 multipurpose.

OK, that's all correct but it mentions nothing about Spotter/Tracer. S/T is M48. M48 was never used as an weapons system ammunition by the military. It was, however, used as a targeting round for the 106mm rifle.  

Quoted: OK, that's all correct but it mentions nothing about Spotter/Tracer. S/T is M48. M48 was never used as an weapons system ammunition by the military. It was, however, used as a targeting round for the 106mm rifle.

I'm still 99.999999999% that this M48 doens't light up in the barrel.  Barrels wouldn't last but a few hundred rounds if that.  Why you could need a different barrel is if the projectiles are really long and needs a different twist rate (just like in ARs).

I've shot approximately 150 rounds of ST BMG in my Barret. They don't trace until well out of the barrel, sometimes not starting till 500m or so.

I know where the munition came from, and have never had a round detonate in the the barrel loaded at bmg specs........

Quoted: I The S/T does light almost right out of the barrel. Velocities are loaded down around 1700 fps to keep the round from detonating in the barrel. Very fun round. www.gibrass.com sells S/T brass but when it is all gone it will be pretty hard to find so twenty years from now it might be hard to feed a rifle chambered for it.

I said it lights ALMOST right out of the barrel. I've shot plenty of Talon's and Ammunitionstore.com S/Ts loaded in 50bmg brass and they all light up within the 50 yard mark at the range.

Additionally, the Spotter Tracer is a TOTALLY DIFFERENT round than the 50bmg, being about an inch shorter, and a different barrel is needed to fire it.

Finally, anyone loading S/T projos up to 50bmg velocities should read 50_Shooter's link above. I went through two and a half cans of Blue Tips before finally getting an air burst out of one. Probably just a matter of time until somebody has an interesting story about  an S/T popping in the tube.

Matter of time indeed, as anything is possible... What do you think is gonna cause the ST round to detonate? Velocity? Heat?

Quoted: Matter of time indeed, as anything is possible... What do you think is gonna cause the ST round to detonate? Velocity? Heat?

From Ammoman.com:

[bold]These bullets were intended only for low pressure applications. Spotter ammunition was loaded to 1745 feet per second, at 38,000 PSI. While the bullet fits a standard 50 BMG case just fine, it was not designed to handle the 50 BMG pressures. If loading these in a 50 BMG case, drop your load down to approach the original velocity and pressure. This is important. This warning is not like the ones on the toaster where it says "Do not make toast while standing in a tub of water."  This one's important!  

Earlier in life, I loaded a few of these for my 50 caliber rifle. Not knowing too much about loading 50 caliber stuff, I decided it might be safest to use the original GI loading. So I pulled the 650 grain bullets from the 50 BMG ammo and placed these bullets right on top of the original powder load, not giving a second thought to the fact that these spotter bullets weigh 813 grains! Oddly enough, most of them worked just fine. Very spectacular trace and huge flash. However, I had a few explode in flight, some almost right in front of the gun! Fortunately, I was there by myself so nobody got hurt, and more importantly nobody saw my dumb trick! What happens, is occasionally the high pressure gas seeps past the tracing compound, past the lead slug, and into the explosive mix. This stuff is all in there tight enough to seal against the 38,000 PSI, but possibly not against the higher pressures of the 50 BMG. [/bold]


Also, about three or four years ago there was a thread on Biggerhammer discussing accelleration forces on the primer at higher velocities having the potential to cause the round to pop.

I can't say for sure that the info isn't pure BS, but you never know.

I'll add this, a friend loaded some S/T with 220 grs of 5010. I don't where he got this, other then thinking it was okay because that's what he was using for regular AP. The S/T round weighs 800+ grs and with 220 grs. of powder behind it.... Let's just say that seeing that round shoot flat and feeling the difference in pressure as it left the barrel will make you step back a few steps.

I don't recommend anyone loading them this high, the max that I've seen for S/T in a fullsize .50 BMG is 190 grs. of 5010. As to the detonation of blue tip or S/T, I think the consenus was that when the bullets were pulled and then resized, it caused a gap between the jacket and the core. When fired, the hot gases from ignition would find it's way through and cause it to go off. Just remember to be safe, it's all fun until someone get's hurt.

50shooter,
But it looked beautiful going down range at sunset!

I just hope he tore down the other ones, if not he's shooting by himself.