BWA 10x100

[coldboreAU]

@Eostech
I am aware that 615 powder was used.
I am only surprised that there were no serious pressure issues.

@badassgunworks
It doesn't matter if the barrel was 50"+, it is still impressive. As long as it is only to achieve high muzzle velocities, any barrel length is acceptable. ( I am talking about the .60/50, also known as .50 HV)

@NightStash
Why don't you just tell us the fps number?
500 grain at XXXX fps...

 

[coldboreAU]

Anyone can claim that their car is the fastest. But claiming and proving is not the same thing.

 

[Eostech]

I am aware that 615 powder was used.
I am only surprised that there were no serious pressure issues.

Why is that surprising though?
To get more velocity you either burn more powder or increase pressure. There is no magical powder formulas, no great efficiency and no secret super low friction barrels or bullets.
You simply use a light of calibre projectile and burn 600 odd grains of powder in a barrel long enough to make use of it.
4-4500 fps at 57K psi is not impressive when you look at these factors, it's mundane.

 

[badassgunworks]

Why is that surprising though?
To get more velocity you either burn more powder or increase pressure. There is no magical powder formulas, no great efficiency and no secret super low friction barrels or bullets.
You simply use a light of calibre projectile and burn 600 odd grains of powder in a barrel long enough to make use of it.
4-4500 fps at 57K psi is not impressive when you look at these factors, it's mundane.

You are mostly correct...

 

[Sandow the Heretic]

Why is that surprising though?
To get more velocity you either burn more powder or increase pressure. There is no magical powder formulas, no great efficiency and no secret super low friction barrels or bullets.
You simply use a light of calibre projectile and burn 600 odd grains of powder in a barrel long enough to make use of it.
4-4500 fps at 57K psi is not impressive when you look at these factors, it's mundane.

You can get higher velocities by having higher sustained pressures rather than simply a peak pressure that falls off. Powder burn rates can thus be optimal or suboptimal vs other powders for that barrel/bullet/cartridge combination. This is why you see big velocity swings with the same reported pressures in load data.

-Alex

 

[brianf]

then you get into the guy who think they can just run the slowest powder available and it will work...until they get secondary burn shock waves half way down the barrel.

 

[Northman623]

I know somebody like this.

 

[brianf]

I know somebody like this.

sorry lolol...i bet he shoots .5 all day too

 

[Taylorbok]

then you get into the guy who think they can just run the slowest powder available and it will work...until they get secondary burn shock waves half way down the barrel.

can you explain this for me? never heard of it.

 

[brianf]

there are several trains of thought on how it actually happens

but they increased the pressure to bolt locking pressures, and they all agree 90%

very slow powder, less than optimized case fill

initial primer strike ignites portion of the powder yet because its not "full" some of the powder gets left behind and smolders

it smolders because of the coatings on the very slow burning powders

then 50-150 milliseconds later the powder ignites and causes another shockwave

usually destroying the case, case head, or locking up the action

originally it was thought that a double charge or over charge was not caught during loading but then they did some tests in the 70's or 80's and they were blowing piezo sensors with a max of 150k psi, under those conditions

...so when guys start playing with these large case capacity necked down cartridges and just toss powder they think should work and shit goes wrong

dont automatically blame the brass case or action for a bad heat treat

 

[Baron23]

Absolutely not a topic on which I have any experience or informed opinions.

But I wonder....why do some of you fellas think this Murica chap...a BR champ, yeah?...is lying?

 

[Sandow the Heretic]

there are several trains of thought on how it actually happens

but they increased the pressure to bolt locking pressures, and they all agree 90%

very slow powder, less than optimized case fill

initial primer strike ignites portion of the powder yet because its not "full" some of the powder gets left behind and smolders

it smolders because of the coatings on the very slow burning powders

then 50-150 milliseconds later the powder ignites and causes another shockwave

usually destroying the case, case head, or locking up the action

originally it was thought that a double charge or over charge was not caught during loading but then they did some tests in the 70's or 80's and they were blowing piezo sensors with a max of 150k psi, under those conditions

...so when guys start playing with these large case capacity necked down cartridges and just toss powder they think should work and shit goes wrong

dont automatically blame the brass case or action for a bad heat treat

I've seen a lot of attempts to explain the phenomenon and while there are a number of reasonable theories, I don't know that anyone has ever measured an event. There was a DoD project trying to replicate it years ago and I think they fired 50% filled 308 cases using a slow powder about 18,000 times and couldn't get one to detonate. They openly acknowledged that it was a potential though. You will see it called "flash over" or simply detonation.

Detonation might be a better technical description of what is happening even if it doesn't explain why. Detonation essentially requires the shockwave to exceed mach 1 (pressure corrected) and when that happens the forces involved are quite a lot higher that a conflagration. Brian can correct me if I'm wrong but my understanding is that the propagation of the flame front from burning powder (not the primer) never exceeds mach 1 since the pressure rise pushes the speed of sound up too high. Perhaps in the detonations the pressure rise is too slow to push the mach value up fast enough. Just a SWAG though.

-Alex

 

[brianf]

I’ll try and find the info and post the link.

I read the 308 sized case trials as well

From what I remember, they got it to happen with larger cases only. Along the lines of 50 bmg powder weight. Not a 300wm sized size case.

 

[coldboreAU]

@Eostech,
615 grains of slow powder is not surprising in itself. 615 grains of powder coming through a 510 bore without too much pressure was a bit surprising.
But it seems to work...

Many cartridges were necked down between 1930-1970.
Even 1.1"/75 cal to 20mm lol.

@badassgunworks

You are mostly correct...

Explain your point of view, if you want.

Absolutely not a topic on which I have any experience or opinions on.

But I wonder....why do some of you fellas think this Murica chap...a BR champ, yeah?...is lying?

I never said he is lying but no matter which person states 4000 fps with regard to big bore calibers 408, 416, 460 etc. I would like to see the numbers on lapradar.

 

[Eostech]

You are mostly correct...

I try to be , what'd I miss? case design efficiency?

You can get higher velocities by having higher sustained pressures rather than simply a peak pressure that falls off. Powder burn rates can thus be optimal or suboptimal vs other powders for that barrel/bullet/cartridge combination. This is why you see big velocity swings with the same reported pressures in load data.

-Alex

Indeed and obviously most the bigger stuff is not in loading manuals let alone variants or wildcats and of course most powder manufactures either didn't predict the current state or won't bother to fill a tiny niche. Put simply if you are in the ballpark with right burn rate, there will not be a new magical powder released that will give you an extra couple hundred fps at the same pressure, same way as I'm deeply suspicious that removing a bit of case taper and changing the shoulder angle will result in magical efficiency that gives you a heap of extra speed for the same pressure by burning some more powder, aka 7SS.

 

[Baron23]

@Eostech,
615 grains of slow powder is not surprising in itself. 615 grains of powder coming through a 510 bore without too much pressure was a bit surprising.
But it seems to work...

Many cartridges were necked down between 1930-1970.
Even 1.1"/75 cal to 20mm lol.

@badassgunworks

Explain your point of view, if you want.


I never said he is lying but no matter which person states 4000 fps with regard to big bore calibers 408, 416, 460 etc. I would like to see the numbers on lapradar.

Hello friend - yes, nobody used the L word but his statement as posted is unambiguous and some here have expressed that they don’t believe it.

Wrt detonation, I’m not an high explosive or firearm propellant expert but I did do some reading on the subject some time ago.

My understanding is that actual detonation, i.e. HE explosion from a shockwave propagating thru the material breaking molecular bonds thus releasing releasing energy, does not happen w smokeless powders.

Smokeless powders do burn very quickly (and yes…the proper term, deflagrate, was referenced above). So, rapid oxidation and breaking of molecular bonds are two very different mechanisms and ner’ the twain will meet.

I looked but at the time I could not find any reference to proof of smokeless powders detonating but this was some time ago. At the time, it was in relation handicap trap shooters firing small mortar shells from 27 yd line and claiming Krieghoff K-80 receivers/Monoblocks were failing due to “detonation”. Meanwhile, while the concept of accumulated metal fatigue from constant high pressure shells seems to have never entered their minds.

At the same time, in over 30 years of shooting tournament skeet I have never heard of a K-80 receiver failing…incl some guns shot in comp for decades.

I’m more than willing to be corrected on any of this as some of you gents seem to know far more on this subject than I.

Oh…and I’ll stop hijacking this thread now! Haha.

 

[Nik H]

I’m more than willing to be corrected on any of this as some of you gents seem to know far more on this subject than I.

Oh…and I’ll stop hijacking this thread now! Haha.

I'll be glad to correct you in September

 

[brianf]

Don’t fight…this is one of the only threads that I’m on which didn’t turn into a shit show lolol

 

[Sandow the Heretic]

My understanding is that actual detonation, i.e. HE explosion from a shockwave propagating thru the material breaking molecular bonds thus releasing releasing energy, does not happen w smokeless powders.

What Brian an I are referring to is a phenomenon in which a low charge of a slow powder is used. Often this is an attempt to get a reduced recoil load for whatever reason. Under normal circumstances, smokeless powder simple burns (quickly) but under these circumstances there is a rare situation in which the result is the gun blowing up.

For black powder, zero free space in the cartridge is reloading 101. You leave a void in a black powder cartridge and the results are more reliably bad. What makes it a vexing problem in smokeless is that it is hard to make it happen and that means the ability to really figure out why it is going boom is much harder.

What makes it stranger from the outside is that the detonations are attributed to very slow powders which is a bit counter intuitive. A few grains of red dot in a 308 is a reliable subsonic load. A mere 100 grains of 20N29 in a 50 BMG is a roll of the dice...

-Alex

 

[badassgunworks]

What Brian an I are referring to is a phenomenon in which a low charge of a slow powder is used. Often this is an attempt to get a reduced recoil load for whatever reason. Under normal circumstances, smokeless powder simple burns (quickly) but under these circumstances there is a rare situation in which the result is the gun blowing up.

For black powder, zero free space in the cartridge is reloading 101. You leave a void in a black powder cartridge and the results are more reliably bad. What makes it a vexing problem in smokeless is that it is hard to make it happen and that means the ability to really figure out why it is going boom is much harder.

What makes it stranger from the outside is that the detonations are attributed to very slow powders which is a bit counter intuitive. A few grains of red dot in a 308 is a reliable subsonic load. A mere 100 grains of 20N29 in a 50 BMG is a roll of the dice...

-Alex

The big issue is low case fill not so much the slow powder there has been many of sub sonic loads that have blown up guns using fast powder as well. Low load density is just not safe ever. Your better off with high case fill with low energy powder for sub sonic. You should never make low case fill ammo its just asking for issues . It is my personal beliefs that too much powder gets ignited at once and to rapid if expansion happens before bullet has
chance to conform . This happens in larger cases more often due to larger powder surfaces and the smaller the bore diamiter the worse like in over bore cases. This issue next to never happens in straight wall cases or shotguns cause its very difficult for them to build pressure. Due to being under bore. Think of it this way if. As powder is subjected to heat and pressure the rate in what it burns is greatly increased if it can get a head start by igniting a larger volume and can expand to fill the void before the bullet moves giving a release it exploads .

 

[Nik H]

Don’t fight…this is one of the only threads that I’m on which didn’t turn into a shit show lolol

No fight...I see @Baron23 every September at a Hide class and he is a constant source of amusement

 

[Baron23]

No fight...I see @Baron23 every September at a Hide class and he is a constant source of amusement

As are you, Nikky! Lol

And I refreshed my 20 year old memory on this subject and my recollection was indeed in error.

Cheers.

 

[stefan73]

What Brian an I are referring to is a phenomenon in which a low charge of a slow powder is used. Often this is an attempt to get a reduced recoil load for whatever reason. Under normal circumstances, smokeless powder simple burns (quickly) but under these circumstances there is a rare situation in which the result is the gun blowing up.

For black powder, zero free space in the cartridge is reloading 101. You leave a void in a black powder cartridge and the results are more reliably bad. What makes it a vexing problem in smokeless is that it is hard to make it happen and that means the ability to really figure out why it is going boom is much harder.

What makes it stranger from the outside is that the detonations are attributed to very slow powders which is a bit counter intuitive. A few grains of red dot in a 308 is a reliable subsonic load. A mere 100 grains of 20N29 in a 50 BMG is a roll of the dice...

-Alex

That's interesting about black powder. I always associated closing the void with BP as being associated to helping to build pressure and get a better/bigger bang versus the sound I make after eating a bunch of street tacos at the local eatery.

 

[coldboreAU]

@brianf, @Sandow the Heretic,
The phenomenon you describe. I have only heard of such problems in connection with less than 90% case fill.
And I have heard, it can happen with all cartridges, not only with large volume cartridges.

The U.S. Air Force had developed and tested numerous cartridges during the 20th century. 1.1 inch shell necked to 20mm. The 20x110 to 50 cal. The 25x137 (currently in service) to 20mm.

With said calibers I can not find a case where this has ever happened.

My opinion, as long as the primer is the right size to properly ignite the powder at 95+% case fill, this phenomenon will not happen.
No matter what cartridge size...

 

[oneshot.onehit]

@oneshot.onehit was running the 416 Warner. That’s close to a 50 down to a 416. Can’t remember the speeds he was getting though

Geno

Sorry a little late here,
As a 50 shortened up and a 375 Warner it was a dang laser beam
361s were easy to run close to 3500
400s did the KO2M finale at 3460

Necked up to a 416 Warner
I only worked with the 550s
doing the 550s and trying to make the brass last forever - still same brass used in the 375 variant just necks expanded
Its nothing to do 3200 with a 550s, Dave and I ran 3110 with back in 2020 then last year we dropped the charge down to float in the 3060 range just because we have concluded there are no gains pushing the 550s faster and aging the brass. 192 grains of 20N29 gets you there even with a bunch of jump. It used to be all about crazy speed but at the end of the day its about being smart and conserving all your resources yet still be a threat in the game of ELR. Some can hot rod all they want they may have deep pockets or belong to a certain click. I’m not about being owned by anyone anymore I did that back in the day with pro archery.

Cheers
osoh

 

[badassgunworks]

@brianf, @Sandow the Heretic,
The phenomenon you describe. I have only heard of such problems in connection with less than 90% case fill.
And I have heard, it can happen with all cartridges, not only with large volume cartridges.

The U.S. Air Force had developed and tested numerous cartridges during the 20th century. 1.1 inch shell necked to 20mm. The 20x110 to 50 cal. The 25x137 (currently in service) to 20mm.

With said calibers I can not find a case where this has ever happened.

My opinion, as long as the primer is the right size to properly ignite the powder at 95+% case fill, this phenomenon will not happen.
No matter what cartridge size...

even small primers will properly ignite large volumes of powder is case fill is high its low case fill that causes the problem
we have been running magnum primers for 250 plus grains for years now and never see delaid ignitions even at very low temps. But the key is fuse timming and case fill.

 

[badassgunworks]

Geno

Sorry a little late here,
As a 50 shortened up and a 375 Warner it was a dang laser beam
361s were easy to run close to 3500
400s did the KO2M finale at 3460

Necked up to a 416 Warner
I only worked with the 550s
doing the 550s and trying to make the brass last forever - still same brass used in the 375 variant just necks expanded
Its nothing to do 3200 with a 550s, Dave and I ran 3110 with back in 2020 then last year we dropped the charge down to float in the 3060 range just because we have concluded there are no gains pushing the 550s faster and aging the brass. 192 grains of 20N29 gets you there even with a bunch of jump. It used to be all about crazy speed but at the end of the day its about being smart and conserving all your resources yet still be a threat in the game of ELR. Some can hot rod all they want they may have deep pockets or belong to a certain click. I’m not about being owned by anyone anymore I did that back in the day with pro archery.

Cheers
osoh

Its about consistancy and accuracy and letting the high bc bullets do there job. You dont need blistering performance . But having the ability to run insane velocities and not means long case life.

 

[Taylorbok]

It used to be all about crazy speed but at the end of the day its about being smart and conserving all your resources yet still be a threat in the game of ELR.

Its about consistancy and accuracy and letting the high bc bullets do there job. You dont need blistering performance . But having the ability to run insane velocities and not means long case life.

How slow do you guys think a person can run a .375cal projectile and still be some what competitive?

I'm hoping to run the 390gr A-tips at around 2900fps out of a 375 RUM improved.

 

[NightStash]

How slow do you guys think a person can run a .375cal projectile and still be some what competitive?

I'm hoping to run the 390gr A-tips at around 2900fps out of a 375 RUM improved.

I’ve won a match with them at 2950.

 

[coldboreAU]

@oneshot.onehit
I never said insanely high muzzle velocity is smart or recommended for ELR competitions. Regarding competitions such as ko2m, you and badassgunworks are right. Yes, accuracy and consistency are more important than something crazy like a 4000 fps desire with heavy bullets.

But for example, nobody needs a 1000 hp muscle car for everyday use, but it's still nice to have one...
And something like a 60 cal was not designed for sports competitions. It was designed to punch holes through steel.
But what needs to be said, that 1200 grain high bc bullets at 3500 fps would outperform any other cartridge currently available.

 

[timintx]

Is it possible that this secondary explosion effect is caused by granules breaking up and exposing the raw untreated powder as they are compressed forward in that particular case design? I remember a P.O. Ackley book I had read that as he went to different shapes to improve the case designs some showed improvements and other did not but one particular design the gun just blew up for no apparent reason so needless to say he did not try improve with that case design any more.

 

[Sandow the Heretic]

Is it possible that this secondary explosion effect is caused by granules breaking up and exposing the raw untreated powder as they are compressed forward in that particular case design? I remember a P.O. Ackley book I had read that as he went to different shapes to improve the case designs some showed improvements and other did not but one particular design the gun just blew up for no apparent reason so needless to say he did not try improve with that case design any more.

The flame front will pass through the space between grains rather fast exposing all surfaces to hot gas. There aren't huge torsional forces inside a case. As pressure rises there will be differentials within the case but not big ones. Pressure force is normal (orthogonal) to all surfaces so the shear forces are pretty limited. If you ever tried to cut a stick powder grain in half you'll remember that propellent grains are pretty strong so I'd be surprised if there was any breaking apart of powder grains rather than them just burning.

Solids only actually burn in vapor phase so heat increases the burn rate and pressure decreases it at any given temp. I'll go back to my previous swag that it is an actual detonation with a supersonic wave inside the combustion volume. If pressure isn't going up fast enough to push back against the heat rise... BOOM! Maybe... Hard to really know in a rare phenomenon trapped within the fiery hellscape of a cartridge.

-Alex

 

[coldboreAU]

The flame front will pass through the space between grains rather fast exposing all surfaces to hot gas. There aren't huge torsional forces inside a case. As pressure rises there will be differentials within the case but not big ones. Pressure force is normal (orthogonal) to all surfaces so the shear forces are pretty limited. If you ever tried to cut a stick powder grain in half you'll remember that propellent grains are pretty strong so I'd be surprised if there was any breaking apart of powder grains rather than them just burning.

Solids only actually burn in vapor phase so heat increases the burn rate and pressure decreases it at any given temp. I'll go back to my previous swag that it is an actual detonation with a supersonic wave inside the combustion volume. If pressure isn't going up fast enough to push back against the heat rise... BOOM! Maybe... Hard to really know in a rare phenomenon trapped within the fiery hellscape of a cartridge.

-Alex

If so, too bad no one is capable of doing a 100k shot study to check exactly when and under what conditions it happens.

Nothing happens only randomly.

 

[badassgunworks]

The cause is low case fill and over bore makes it worse primer fires across top of column and ignites too muck powder at once. A spike happens and doom bolt in the head

 

[Eostech]

If so, too bad no one is capable of doing a 100k shot study to check exactly when and under what conditions it happens.

Nothing happens only randomly.

With any sort of troubleshooting an intermittent fault is a pain in the ass so while something might not be completely random that doesn't make it any easier to diagnose. Worse still is people generally have the aftermath of a catastrophic failure to shift through in order to find a cause.

 

[Sandow the Heretic]

The cause is low case fill and over bore makes it worse primer fires across top of column and ignites too muck powder at once. A spike happens and doom bolt in the head

I've heard this theory a number of times and I believe that it is wrong. If you are thinking that powder burns in a full case from the rear forward, and that the "flash over" increases the amount of powder ignited I think that is based on some assumptions about how ignition really works. A flash tube starts the ignition in the middle of a case and doesn't double your pressures. It may lend towards higher velocity consistency though. This essentially means that regardless of how it gets going, the majority of the case volume is flooded with hot gas from the primer which ignites a significant fraction of the powder at once.

In really big cases with undersized primers, that doesn't hold up. 700 Nitro loaders often end up with a few grains of red dot at the bottom of a compressed load of a 50BMG powder to help get complete ignition. That is the same powder volume as 50BMG with a large magnum primer though so lets call that a special case...

-Alex

 

[LeftyJason]

I've heard this theory a number of times and I believe that it is wrong. If you are thinking that powder burns in a full case from the rear forward, and that the "flash over" increases the amount of powder ignited I think that is based on some assumptions about how ignition really works. A flash tube starts the ignition in the middle of a case and doesn't double your pressures. It may lend towards higher velocity consistency though. This essentially means that regardless of how it gets going, the majority of the case volume is flooded with hot gas from the primer which ignites a significant fraction of the powder at once.

In really big cases with undersized primers, that doesn't hold up. 700 Nitro loaders often end up with a few grains of red dot at the bottom of a compressed load of a 50BMG powder to help get complete ignition. That is the same powder volume as 50BMG with a large magnum primer though so lets call that a special case...

-Alex

Not sure if this is relevant or not at all. My brain jumped to it reading this post.

 

[badassgunworks]

I've heard this theory a number of times and I believe that it is wrong. If you are thinking that powder burns in a full case from the rear forward, and that the "flash over" increases the amount of powder ignited I think that is based on some assumptions about how ignition really works. A flash tube starts the ignition in the middle of a case and doesn't double your pressures. It may lend towards higher velocity consistency though. This essentially means that regardless of how it gets going, the majority of the case volume is flooded with hot gas from the primer which ignites a significant fraction of the powder at once.

In really big cases with undersized primers, that doesn't hold up. 700 Nitro loaders often end up with a few grains of red dot at the bottom of a compressed load of a 50BMG powder to help get complete ignition. That is the same powder volume as 50BMG with a large magnum primer though so lets call that a special case...

-Alex

Sorry Alex you are mistaken I have several cartridges but my design that are not based on any parent case that I run well over 250 grains of BMG powder with a magnum primer with absolutely no issues whatsoever have been doing it for years. It is all about fuse timing. The reason why the 700 Nitro has issues it's because it's a straight wall case and does not build the pressure that is needed

 

[Sandow the Heretic]

Sorry Alex you are mistaken I have several cartridges but my design that are not based on any parent case that I run well over 250 grains of BMG powder with a magnum primer with absolutely no issues whatsoever have been doing it for years.

How are you determining powder ignition and burn characteristics? Sonic sensors on the chamber and barrel? A bit surprising if true since even with 50BMG primers in a 50BMG cartridge, the hotter IMI and RWS primers perform more consistently than the CCIs which implies the primer which is around 5 times as potent as a magnum primer is potentially still underpowered.

-Alex

 

[badassgunworks]

Changing the fuse timing by changing the flash hole diameter in length. Even the BMG case can be properly ignited with a standard Magnum primer. Those who have tested it unsuccessfully we're using bushings that did not change the flash hole only the pocket

 

[badassgunworks]

Flash tubes create cold spots one of the reasons why they are not dangerous biggest problem is they're not consistent a standard primer igniting from the back of the case only has cold spots around the base of the case head you're also not running lower Caseville with a Foward ignition system. The standard primer system only initially ignites a very small percentage of the powder it is it's hot expanding gases that filters itself throughout the entire column. What a primer fires across the top of an empty void too much of the powder is ignited and and the problem is exaggerated and made worse with a larger Supply of oxygen and expansion area this does create a spike. One of the reasons why it is not always consistent from a negative aspect or results is that the powder is never displaced inside the case evenly. There are a lot of factors like for example burn characteristics of a specific powder. The combination of volume versus bore diameter versus bearing Surface versus projectile weight my guess would be that in the right scenario the problem could be duplicated often quite easily

 

[badassgunworks]

Forward ignition systems only seem to be advantageous when you have a surplus of powder in very long barrels with extremely heavy projectiles where slower powder is needed that does not exist

 

[coldboreAU]

@badassgunworks
I absolutely agree with everything you have said so far.

@Eostech
Searching and finding errors has never been easy. But I think as long as there are things we don't know about powder, primer and firearms, we should test until we know. Even when it comes to something that can cause catastrophic failure.

But please note, i'm talking about doing it safe. I'm not talking about testing it until the gun blows up right in our face.

However, I doubt that the error described by brian and alex shows up at 95+% case fill, or the primer used must be the last garbage.

Not to mention that there are some very slow burning powders where there is not even much space between the kernels.
Slower burn rate does not always mean bulkier powder.

With something stupid like 100 grain in a 50 bmg case, yes I agree with everyone, it's like rolling dice...

 

[coldboreAU]

Brian, before I'm out, I want to make something clear here.
I have nothing against you and Alex.
But your start post is indirectly the point that confuses me totally.

Alex said this Quote
"You can get higher velocities by having higher sustained pressures rather than simply a peak pressure that falls off. Powder burn rates can thus be optimal or suboptimal vs other powders for that barrel/bullet/cartridge combination. This is why you see big velocity swings with the same reported pressures in load data."

I completely agree with this post.

Your next 2 posts were Qute
"then you get into the guy who think they can just run the slowest powder available and it will work...until they get secondary burn shock waves half way down the barrel."
AND
"there are several trains of thought on how it actually happens

but they increased the pressure to bolt locking pressures, and they all agree 90%

very slow powder, less than optimized case fill

initial primer strike ignites portion of the powder yet because its not "full" some of the powder gets left behind and smolders

it smolders because of the coatings on the very slow burning powders

then 50-150 milliseconds later the powder ignites and causes another shockwave

usually destroying the case, case head, or locking up the action

originally it was thought that a double charge or over charge was not caught during loading but then they did some tests in the 70's or 80's and they were blowing piezo sensors with a max of 150k psi, under those conditions

...so when guys start playing with these large case capacity necked down cartridges and just toss powder they think should work and shit goes wrong

dont automatically blame the brass case or action for a bad heat treat"

Do you realize what this would theoretically mean, if true?
That would mean overbore wildcats (375/50 , 50/20 , 14.9mm etc..) with very slow powder would be unsafe.

It could happen (partly random)
that the primer ignites only a small portion of the powder. The rest of the powder is left to smolder until it ignites a 1/4 second later and the second shock wave detonates the gun. (In my humble words...)
Or at least it will lock up the action.

I have heard of such a phenomenon, such a chain reaction but never with reference to high case filling.

Don't take it too bad, I don't want to attack you.

Just my last 2 pennies...

 

[brianf]

Never personal…especially when you have a good argument/question.

I’ll find the info when back at work on Tuesday, hopefully I can find the link in history.

I do agree that a proper case fill is most likely 90% of the issue when talking wolf cats/necked down big volume cases.

I think one study tried it in a 308 and after 18,000 rounds it only happened a few times which is insignificant statistically.

 

[KasuganoKanade]

any updates on this round? or is this round dead already?

 

[deadontheX]

any updates on this round? or is this round dead already?

It's a dead horse and loui murdica's wild claims are bullshit, in my opinion. First he claimed 415 grain bullet at 4000 fps and few weeks or months ago on facebook he wrote 4200 fps. But he refuses to answer any questions about the rifle, caliber and how he achieves this performance. He does not show up at ELR competitions with his 4000 fps super rifle. So logical conclusion it's all BS.

 

[lash]

It's a dead horse and loui murdica's wild claims are bullshit, in my opinion. First he claimed 415 grain bullet with 4000 fps and few weeks or months ago on facebook he wrote 4200 fps. But he refuses to answer any questions about the rifle, caliber and how he achieves this performance. He does not show up at ELR competitions with his 4000 fps super rifle. So logical conclusion it's all BS.

Exactly. Believe none of what you hear and half of what you see.

 

[KasuganoKanade]

It's a dead horse and loui murdica's wild claims are bullshit, in my opinion. First he claimed 415 grain bullet at 4000 fps and few weeks or months ago on facebook he wrote 4200 fps. But he refuses to answer any questions about the rifle, caliber and how he achieves this performance. He does not show up at ELR competitions with his 4000 fps super rifle. So logical conclusion it's all BS.

Ah I see, was kinda excited since Cadex up here is actually trying to make it a factory production for this caliber. Yeah I was kinda skeptical when I heard those numbers too, in order for a 415gr bullet reaching 4000fps using any magnum powders would blow the chamber up in my opinion, let alone 4200fps. But hey im not an expert so what do I know lol. However, leaving out the numbers, is this round actually achievable and practical?

 

[badassgunworks]

Ah I see, was kinda excited since Cadex up here is actually trying to make it a factory production for this caliber. Yeah I was kinda skeptical when I heard those numbers too, in order for a 415gr bullet reaching 4000fps using any magnum powders would blow the chamber up in my opinion, let alone 4200fps. But hey im not an expert so what do I know lol. However, leaving out the numbers, is this round actually achievable and practical?

Here is the issue blackwater was claiming and hoping for 3500 fps with a light per csliber .408 bullet please note a light per caliber 408 bullet would have a shitty bc. So end results would perhaps be no better past 2500 yards then a high bc 375 cheytac going 3000 fps. Second issue claims of some one shooting the round at 4200 fps with a heavier bullet is way beyond that of the projected velocity that blackwater was hoping for and has produced nothing to the public as to ever exceeding it. So if they had trust me we all would of heard about them bragging about it by now. The cartridge case used by lou was a lathe turned Rcc case. And trust me if any one knows about limits of lathe turned cases in 272 alloy your speaking to him. In short. Its not going to happen by that design. His barrel was not long enough . Even If the case was beefed up to handle the pressures there are many other issues like the action not being designed to handle pressures needed to have his claimed results he also claimed special extra slow powder that would have a negative out come with his barrel length. There is no free lunch when it comes to performance based results and designs