Guns and Ammo Thread

[almostgone]

This sheds some light on a discussion were were having several posts ago about suppressors on machine guns.

Video of the Army testing its new "smuzzle" (suppressor-muzzle brake) on (7.62) M-240:



By my reckoning they run about 670 rounds through it non-stop in about 62 seconds, which would be consistent with the 240's gas setting #1, which by the book is 650-750 rpm.

And nothing fails. There's nothing even glowing (in this light) except the can. My G**gle-fu is faltering and I can't discover what it's made from, but I'll keep looking.

IMHO they squandered an opportunity by not testing it to failure. Seems to me that any engineer worth his salt would want to know when that happens and how (mean time between failures/mean rounds between stoppages). But in typical military fashion, they probably only tested it to meet a minimum standard.

It would have to be one of the superalloys to overcome thermal creep. Surefire favors stainless steel and Inconel on most of their stuff as far as I know

Other than welds, I wonder if tungsten/Wolfram is in the mix as it has the highest mp of any metal @ 3,422°C.

I'd be interested to know myself.

[Beetlegeuse]

It would have to be one of the superalloys to overcome thermal creep. Surefire favors stainless steel and Inconel on most of their stuff as far as I know

Other than welds, I wonder if tungsten/Wolfram is in the mix as it has the highest mp of any metal @ 3,422°C.

I'd be interested to know myself.

The magic ingredient in turbine engine impellers is rhenium, which melts at close to 5800 °F and is rarer than hobby horse turds. And if you've gone that far you've got yourself into a bidding war with the like of GE, Pratt & Whitney and Rolls Royce. The stuff is like $3 a gram. Which is chicken feed to a military budget, especially as crazy high-tech and astronomically expensive as military hardware has become.

OT but did you know some of the latest Apache helicopters have their own reconnaissance drone? And not only that, they're developing autonomous tanks to fight along side a manned tank. They're calling it the "wing man" tank. Because we can build a new "wing man" faster than we can train up a new tank crew.

Ike Eisenhower tried to warn against the military-industrial complex taking control of the military, and I have to wonder if we're not close to (if not beyond) that point. But there's no doubt we've fallen down the hi-tech rabbit hole. Our new order of battle is full of "force multipliers" that promise to improve our warfighting but at the same time reduce the potential casualties on our side. But the risk is it's only an effective strategery for so long as we can maintain our technological lead. And for as long as the batteries don't run out. And nobody introduces EMP into the battlefield.

Speaking of turbines, the temperature inside the combustion section is high enough to melt the walls of the burner can but they prevent the flame from touching the walls by using laminar air flow as a barrier. That's why the start procedure for all turbine engines includes energizing the starter motor until the gas producer section is at a minimum RPM before introducing fuel. That establishes the laminar flow before you light the fire. I remember that in the Army's OH-58/Bell Jet Ranger -- which had a completely manual start procedure -- you motored until the N1 gauge (compressor section) was at 12% RPM before opening the throttle to flight idle. If you're ever around a turbine when it's starting you can usually make out the two phases. You can even tell whether the sound of the starting engine you hear on TV or in a film is for real by listening for this. When cranking starts you can hear a sort of a low roar with a faint whistle not unlike turbocharger noise. And sometimes you can hear the rapid clicking of the igniter, which only needs to run until the flame is lit because the flame is self-sustaining. This might only take a couple of seconds until they introduce the fuel. But you can't mistake that because in an instant the low roar becomes very pronounced, drowning out the whistle, and the clicking stops. You might see flames shooting outs its ass when that happens.

Anyway, all that to get to this. I can't recall the source but I seem to recall scanning an article in the last few weeks about some new suppressor that uses (or at least attempts to use) laminar flow to insulate the suppressor body. Some of the suppressors now use voodoo to redirect all the pressure forward to prevent overgassing the action or the blowback of vaporized copper. This one tried to engineer that forward flow to create that laminar barrier and give the suppressor body some temperature relief. But I didn't pay the article much mind because at best it seems such a tiny volume of air in comparison, and I can't imagine it would be very much return on the investment. But hey, from tiny acorns, might oak trees grow.

[charger69]

The magic ingredient in turbine engine impellers is rhenium, which melts at close to 5800 °F and is rarer than hobby horse turds. And if you've gone that far you've got yourself into a bidding war with the like of GE, Pratt & Whitney and Rolls Royce. The stuff is like $3 a gram. Which is chicken feed to a military budget, especially as crazy high-tech and astronomically expensive as military hardware has become.

OT but did you know some of the latest Apache helicopters have their own reconnaissance drone? And not only that, they're developing autonomous tanks to fight along side a manned tank. They're calling it the "wing man" tank. Because we can build a new "wing man" faster than we can train up a new tank crew.

Ike Eisenhower tried to warn against the military-industrial complex taking control of the military, and I have to wonder if we're not close to (if not beyond) that point. But there's no doubt we've fallen down the hi-tech rabbit hole. Our new order of battle is full of "force multipliers" that promise to improve our warfighting but at the same time reduce the potential casualties on our side. But the risk is it's only an effective strategery for so long as we can maintain our technological lead. And for as long as the batteries don't run out. And nobody introduces EMP into the battlefield.

Speaking of turbines, the temperature inside the combustion section is high enough to melt the walls of the burner can but they prevent the flame from touching the walls by using laminar air flow as a barrier. That's why the start procedure for all turbine engines includes energizing the starter motor until the gas producer section is at a minimum RPM before introducing fuel. That establishes the laminar flow before you light the fire. I remember that in the Army's OH-58/Bell Jet Ranger -- which had a completely manual start procedure -- you motored until the N1 gauge (compressor section) was at 12% RPM before opening the throttle to flight idle. If you're ever around a turbine when it's starting you can usually make out the two phases. You can even tell whether the sound of the starting engine you hear on TV or in a film is for real by listening for this. When cranking starts you can hear a sort of a low roar with a faint whistle not unlike turbocharger noise. And sometimes you can hear the rapid clicking of the igniter, which only needs to run until the flame is lit because the flame is self-sustaining. This might only take a couple of seconds until they introduce the fuel. But you can't mistake that because in an instant the low roar becomes very pronounced, drowning out the whistle, and the clicking stops. You might see flames shooting outs its ass when that happens.

Anyway, all that to get to this. I can't recall the source but I seem to recall scanning an article in the last few weeks about some new suppressor that uses (or at least attempts to use) laminar flow to insulate the suppressor body. Some of the suppressors now use voodoo to redirect all the pressure forward to prevent overgassing the action or the blowback of vaporized copper. This one tried to engineer that forward flow to create that laminar barrier and give the suppressor body some temperature relief. But I didn't pay the article much mind because at best it seems such a tiny volume of air in comparison, and I can't imagine it would be very much return on the investment. But hey, from tiny acorns, might oak trees grow.

There are actually a number of magic ingredients in turbine components. I can’t remember the % of Rhelium but it is very minute. However the main ingredients are either cobalt based or nickel based. The cobalt base is used right outside the burner can on the T1 vanes. The nickel based usually start after that. The matrix formation also plays an important role with the introduction of the single crystal ( probably in the 1990’s.
Most of the materials technology that they are using is from the 50’s and 60’s on commercial jets. Yes there have been minor changes, but other than single crystal it’s essentially the same.
There are so many factors, but Above 2100 F ( I am referring to time based exposure) you start to see structure changes in the metal matrix which results in an “over temp” condition and deems the part non usuable.
You are never going to have perfect flow in a turbine engine. There are no requirements for profiles on the turbine blades and vanes once they go through the repair cycle.
The V2500 has this whistling even while operating. You can tell right off the bat that it is a V2500.


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[Beetlegeuse]

... There are so many factors, but Above 2100 F ( I am referring to time based exposure) you start to see structure changes in the metal matrix which results in an “over temp” condition and deems the part non usuable. ..

In a previous life I ran tech control and QC on a carburizing and carbo-nitriding operation in a manufacturing plant so I grok Spock ...



... and metal matrices.


Which is why I have arguments without end with reloaders who insist that what they're doing to their brass is "annealing" it.

[almostgone]

In a previous life I ran tech control and QC on a carburizing and carbo-nitriding operation in a manufacturing plant so I grok Spock ...



... and metal matrices.


Which is why I have arguments without end with reloaders who insist that what they're doing to their brass is "annealing" it.

...more like work hardening it they way some of them overcrimp.