The World of Cartridges and Compromises........

Others refer to this a powder bridging, it mostly (from what I've read ) happens in overbore cartridges.
best solution (again from what Ive read) is to use ball powders.
Not the first time this has happened IF thats what happened.
 
todbartell said:
Boomer, do you think this situation could happen in other cartridges, such as a 270, 7mm or 300mag. Or is it unique to a 375 ultra sized cartridge and its large diameter bullet creating more potential force on the charge weight .
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I believe it is only possible with large volume cases and unusually heavy bullets. A .300 mag with 230s or 240s don't have the capacity, but a .30-378 or .300 Ultra might produce the correct conditions if my assumptions are correct. I don't think there are bullets sufficiently heavy for bore size in the .416 Rigby or Weatherby, which would require 468 grs but a 600 gr slug in a .450 Rigby or .460 Weatherby would qualify, but the big .458s capacity isn't so overbore that you'd consider a slow powder like Retumbo.
 
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marshman said:
Others refer to this a powder bridging, it mostly (from what I've read ) happens in overbore cartridges.
best solution (again from what Ive read) is to use ball powders.
Not the first time this has happened IF thats what happened.
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That's interesting, and I believe brings us closer to the cause of the incident, remind me not to build a 6.5-378. Your post led me to find this, which answers the question of whether powder hanging up in a funnel or thrower is related . . .

NoRobbor,

Powder Bridging is basically the same thing you discribed but in the opposite direction under alot more pressure!!

Basically, when X amount of powder is trying to pass through a certain diameter hole, it has a limit in how fast the powder can flow through this opening.

With a very large case capacity round with a modern, sharp shoulder angle, this becomes a problem with smaller caliber cases. Now this depends on the caliber as well as the diameter of the case powder column and the total powder volume.

What happens is when a round is ignited by the primer, the blast from the primer forces the powder in the case foward until it is stopped by the shoulder and seated bullet. Then it begins to ignite.

As the pressure inside the case increases from the rear of the case forward, it increases the pressure on the powder. Powder bridging occurs when the pressure actually locks the powder granuals together because they simply can not pass though the neck of the case and pressure increases dramatically.

In the case of my Allen Mags, the 257 and 6.5mm are the only two that so far have had this problem. The simple cure is to use Ball powder. This solves the problem simply because this powder shape can flow at MUCH higher rates through even smaller neck diameters then any stick powder.

In the 270 and larger Allen Magnums, this has not been a problem at all but I still generally use the real slow burning ball powders simply because of their lower burn temps and they are much easier on the throat of the chamber as the powder is forced through.

Hope this helps some.

Kirby Allen(50)
 
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Boomer said:
So you are suggesting that a balance beam scale that is zeroed to the exact charge weight, that must produce 2 consecutive, identical reading has hung up. I don't think so. I disagree with your loading technique. There is no need to visually inspect a load that fills the case, although it is beneficial when loading reduced rifle loads with pistol powder. Having a cartridge block on the bench that is full of charged cartridges is just asking for contamination if you get called away before finishing, to say nothing of what is going to happen to you if the light bulb above your bench explodes. For a smart guy, you take some unnecessary chances, but it doesn't matter, your loading career is over once you shoot that safe load you just got from QL.
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You have become defensive, probably for good reason. I do not run incandescent 'lamps' over my bench, its 2016btw.

You have no room to crow about handloading techniques, Boom-Boomer-Kafukenboomfka

QL is not a faith based program, its pure science and works very well given the proper inputs and understanding.

As you worked up that load were you getting expected incremental increases in velocity?
Did you shoot a broad enough sample at each charge weight to discern an ES trend?
Do you know what a wide ES means in-spite of meticulous charge weight control?

The beauty of the LabRadar is every shot can be recorded as you work up your load, and its accurate to 0.1%, you look for ES changes.
An personal example is ,years ago I had a 35 Whelen with a lot of freebore with a 250gr FXB and a max suggested load of 55gr Varget it ran ~2300 ft/s, should be up around 2500 ft/s. So I seat the bullet one caliber and incrementally increase powder charge.....got to 2700+ft/s with no traditional pressure signs, this took 63gr of powder, all should be good ya! It was not, the ES was all over the map, this suggests erratic ignition/burn . So, I back off to 61gr of powder and 2650 ft/s and ES fell to the near single digits.

I heeded the warning, you may not have.

In your new 375 try 76.5gr of RL-17, you can thank me later :)
 
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BCBRAD said:
You have become defensive, probably for good reason. I do not run incandescent 'lamps' over my bench, its 2016btw.

You have no room to crow about handloading techniques, Boom-Boomer-Kafukenboomfka

QL is not a faith based program, its pure science and works very well given the proper inputs and understanding.

As you worked up that load were you getting expected incremental increases in velocity?
Did you shoot a broad enough sample at each charge weight to discern an ES trend?
Do you know what a wide ES means in-spite of meticulous charge weight control?

The beauty of the LabRadar is every shot can be recorded as you work up your load, and its accurate to 0.1%, you look for ES changes.
An personal example is ,years ago I had a 35 Whelen with a lot of freebore with a 250gr FXB and a max suggested load of 55gr Varget it ran ~2300 ft/s, should be up around 2500 ft/s. So I seat the bullet one caliber and incrementally increase powder charge.....got to 2700+ft/s with no traditional pressure signs, this took 63gr of powder, all should be good ya! It was not, the ES was all over the map, this suggests erratic ignition/burn . So, I back off to 61gr of powder and 2650 ft/s and ES fell to the near single digits.

I heeded the warning, you may not have.

In your new 375 try 76.5gr of RL-17, you can thank me later :)
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I'm not being defensive at all. I have nothing to prove, and am unafraid to bring experiences either good or bad to the discussion. You're the one who has gone to some length to illustrate your lack of experience by promoting risky behavior, all the while promoting yourself as an expert. Yet despite that, you are incapable of admitting that there are some things that a computer program cannot predict, as if it was you who invented the program. What I ran into is best described as an anomaly; not a mistake, an oversight, or an omission. Powder bridging seems to be the most promising theory yet, given the powder capacity of the cartridge, the large particle size of Retumbo, combined with a heavy bullet.

As for LabRadar chronographs, I've heard of them . . . http://www.canadiangunnutz.com/forum/showthread.php/1102854-Mylab-Radar.

R-17? I might try some in my .308 when I run out of N-550, it would even be a top choice in a .375 H&H or a .375 Ruger, but its too fast for a .375 Ultra with the bullet weights I prefer to use. R-19 is the sweet spot, slower than 4350, but faster than H-4831. The fast powder I use in this cartridge is Unique.
 
Boomer said:
So you are suggesting that a balance beam scale that is zeroed to the exact charge weight, that must produce 2 consecutive, identical reading has hung up. I don't think so. I disagree with your loading technique. There is no need to visually inspect a load that fills the case, although it is beneficial when loading reduced rifle loads with pistol powder. Having a cartridge block on the bench that is full of charged cartridges is just asking for contamination if you get called away before finishing, to say nothing of what is going to happen to you if the light bulb above your bench explodes. For a smart guy, you take some unnecessary chances, but it doesn't matter, your loading career is over once you shoot that safe load you just got from QL.
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I've had my 5-0-5 hang up on numerous occasions, especially when I'm forgetful on putting the scale away and doing
dusty and sawdusty chit out in the shop.
I balance the beam, set weight and toss a few charges on the pan.
Sometimes I need to tap the scale with me tweezers to get it to move.
Then it is time to blow off the wedgies the scale bar sits in.
Yes, Boomer, it has happened to me.
 
kamlooky said:
I've had my 5-0-5 hang up on numerous occasions, especially when I'm forgetful on putting the scale away and doing
dusty and sawdusty chit out in the shop.
I balance the beam, set weight and toss a few charges on the pan.
Sometimes I need to tap the scale with me tweezers to get it to move.
Then it is time to blow off the wedgies the scale bar sits in.
Yes, Boomer, it has happened to me.
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My balance beam scale has taken to hanging up once in a while starting a couple years back. No rhyme no reason for it doing so as it is kept in it's original box when not in use. The scale is 42 years old, maybe that's it. I bought a new balance beam scale and I also have a RCBS scale /powder charge thrower. I check the RCBS against the both the balance beams now. If the RCBS throws 5 consistent charges that the beam scale confirms I consider we are good to proceed. Plus every now and then I will dump a charge on the beam scale just to ensure we are on track. Funny how that Lyman scale started to hang up every once in a while, just a slight puff of air will get it moving again.
 
What makes you say it is too fast, what does this chart tell you?

It's bang on a node at 1.31 mS for a 22" barrel.

Just ran a RL-19 model.......laughing

 
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BCBRAD said:
What makes you say it is too fast, what does this chart tell you?

It's bang on a node at 1.31 mS for a 22" barrel.

Just ran a RL-19 model.......laughing
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That's the problem with computer generated predictions, they make you think you know more than you do. Buy yourself a rifle in .375 Ultra, I'll send you a few bullets at my cost, if you promise to use Retumbo first, and then you'll know.
 
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kamlooky said:
I've had my 5-0-5 hang up on numerous occasions, especially when I'm forgetful on putting the scale away and doing
dusty and sawdusty chit out in the shop.
I balance the beam, set weight and toss a few charges on the pan.
Sometimes I need to tap the scale with me tweezers to get it to move.
Then it is time to blow off the wedgies the scale bar sits in.
Yes, Boomer, it has happened to me.
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Sure, but it became obvious you had a problem, you resolved the problem by "blowing off the wedgies" and the scale returned to its reliable old happy self. I wasn't saying a scale can't hang up, but its evident when it does, and you don't trust the readings from it until you've resolved the problem.
 
I will just go on record that seeing an experienced reloader and firearms enthusiast like boomer posting his personal experience and watching others trying to write him off is concerning......

It happened..... Boomer has been forthright..... Maybe we could all learn a lesson here?......
 
Boomer said:
That's the problem with computer generated predictions, they make you think you know more than you do. Buy yourself a rifle in .375 Ultra, I'll send you a few bullets at my cost, and then you'll know.
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I have had good success with computer modeling hand loads, not saying it can't be done by traditional methods, but modeling saves a lot of time gets you on to a barrel node, dispels old myths on what works and doesn't and lowers ES with optimization of the powder burn.

I don't think I know more than I do, but the advantage is using available tools to make things better or at least easier.

The chart above will get the best out of your cartridge combination, it runs 2311 ft/s btw.

The QL program is really quite simple in concept, Optimum burn of the powder and barrel time, it does take time to study the program though.

I could walk you through the basics but your dug in now.
 
Superbrad said:
I will just go on record that seeing an experienced reloader and firearms enthusiast like boomer posting his personal experience and watching others trying to write him off is concerning......

It happened..... Boomer has been forthright..... Maybe we could all learn a lesson here?......
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He puts it off as an anomaly.

So, nothing to learn here..........move along.
 
Superbrad said:
You have a lot to learn from your superiors....... And you are getting borderline abrasive.......

Maybe boomer made a mistake, maybe he didn't...... But we can all learn from it.......
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I'm looking for a take away here and all I get "Guess it was an anomaly"

Passive aggressiveness does make one rise to the challenge :)
 
BCBRAD said:
I have had good success with computer modeling hand loads, not saying it can't be done by traditional methods, but modeling saves a lot of time gets you on to a barrel node, dispels old myths on what works and doesn't and lowers ES with optimization of the powder burn.

I don't think I know more than I do, but the advantage is using available tools to make things better or at least easier.

The chart above will get the best out of your cartridge combination, it runs 2311 ft/s btw.

The QL program is really quite simple in concept, Optimum burn of the powder and barrel time, it does take time to study the program though.

I could walk you through the basics but your dug in now.
Click to expand...

What "node" is QL showing you? I think of a node as the sweet spot in barrel harmonics as it relates to accuracy. QL sure as hell won't save you any time here.
 
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