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

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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Why would you suggest a load like this for someone on the internet. If you seriously run a chart like this and then hit the loading room then I think it's safe to say you're in for a rude awakening one day.
 
cdn shooter said:
This is 2gr over the 60,000psi load shown on your chart.

My advice is...stop giving load advice. You and your lawyer can thank me later.
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Ya, probably shouldn't of suggested that load, it's predicted to run 63.7K which is just under max. But hey, Boomer runs them until failure anyway.

Generally for hunting I usually take the lower node, but for competition will run 65K sometimes more if I can catch the higher node and get optimized burn which produces a stable load.
 
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Interesting discussion, always lots too learn. If I had some retumbo I would try filling up a case and seating a bullet deeply and letting it sit for a few days myself. See if it turns into a pellet or cake. Or maybe the granules get crushed and change the burn rate.
 
Boomer said:
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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300 RUM with a 240gr (Woodleigh, or SMK) would be 100% load density @ 65k PSI chamber pressure, so you wouldn't be able to run a compressed load in that case. 30-378 / Retumbo 65kPSI in the 94% load density ballpark. You won't even get 110% LD with even the slowest fuels on the market with these cartridges.

If this kaboom only happens in a 375 RUM shooting 380's over 112+% Retumbo loads, you're probably the only guy who will ever experience that kaboom.
 
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.
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Exactly, now you see that R-17 is too fast for this application, less that optimal velocity combined with too small a powder charge in the cartridge, you might be catching on. Ideally the 380 gets 2350 with a powder charge of 82-85 grs for 95%-100% loading density. H-4350 produced the same velocity you guessed with R-17, but it did so with a 95% load density that produced groups like this . . .

Not too bad for a rifle topped with a 2.5X scout scope, fired from slung up prone, and a long heavy bullet fired from a standard twist barrel . . .


Extreme spread is a useful tool to see if you're on the right track, but in of itself is no guarantee of accuracy, when other elements of load development are ignored, such as having a clue about the correct burning rate for a given application.
 
todbartell said:
300 RUM with a 240gr (Woodleigh, or SMK) would be 100% load density @ 65k PSI chamber pressure, so you wouldn't be able to run a compressed load in that case. 30-378 / Retumbo 65kPSI in the 94% load density ballpark. You won't even get 110% LD with even the slowest fuels on the market with these cartridges.

If this kaboom only happens in a 375 RUM shooting 380's over 112+% Retumbo loads, you're probably the only guy who will ever experience that kaboom.
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Perhaps, but now that I've considered the possibility of of powder bridging, the small bore cartridges having AI, Weatherby and Nosler profiles are all contenders for the kaboom award if heavy loads of a coarse, extruded powder are loaded. A 6.5-378 anyone?
 
todbartell said:
300 RUM with a 240gr (Woodleigh, or SMK) would be 100% load density @ 65k PSI chamber pressure, so you wouldn't be able to run a compressed load in that case. 30-378 / Retumbo 65kPSI in the 94% load density ballpark. You won't even get 110% LD with even the slowest fuels on the market with these cartridges.

If this kaboom only happens in a 375 RUM shooting 380's over 112+% Retumbo loads, you're probably the only guy who will ever experience that kaboom.
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You could be right, in any case I don't recommend it, its hard on the ears, hard on the eyes, hard on facial skin, hard on the fingers of the shooting hand, hard on the wife, and particularly hard on the rifle.
 
BCBRAD said:
He puts it off as an anomaly.

So, nothing to learn here..........move along.
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He also knows anomalies happen for a reason, they are never by chance. That means if the same parameters are repeated, the same end result is inevitable. You might have nothing to learn but I and others continue to learn and add to our knowledge base though experience and discussion with like minded people. You might be a little out of your depth here. Hows that for passive aggressive?
 
Boomer Boomer Boomer, if you had taken the inclination to expand your horizons through the available technology you would have given yourself the opportunity to model an almost endless combination of components for your 375 RUM.

The methodology here is to lay out the criteria for the load, what game pursued, distance game animal will likely be dispatched, bullet that will get to the animal and perform properly for a humane kill and accuracy required for the task.

OR

I want to use a boutique bullet in my 375 and I want to use Retumbo powder because, well I just want to, and I have a #### load of Retumbo. You have some information that you can run the bullet 2350 ft/s and by george she's agona run 2350 ft/s, hell or high water.

IF

You took a scientific approach to knocking down those high mountain elephants you would realize that your dream was just that. But the 375 RUM is quite capable in its standard/common loadings but I'll give you that Mt Elephant might tax its ability. In many industries modeling has taken the place of over-engineering and trail and error to produce a product or end result.

My handloading hobby has spanned over 4 decades and with the availability of an accurate velocity measuring device, Quickload (internal ballistics), and external ballistic programs. My loads are safer and more accurate than anytime before. And , the bonus here less resource spent on load development and more time slamming steel and drilling X rings.

I have many first hand samples of this that I can discuss with you. However, that won't be until next week as we are off to the Kootenays, hopefully there is time to check for Mt Elephant sign.

Have a great week.
 
BCBRAD said:
Boomer Boomer Boomer, if you had taken the inclination to expand your horizons through the available technology you would have given yourself the opportunity to model an almost endless combination of components for your 375 RUM.

The methodology here is to lay out the criteria for the load, what game pursued, distance game animal will likely be dispatched, bullet that will get to the animal and perform properly for a humane kill and accuracy required for the task.

OR

I want to use a boutique bullet in my 375 and I want to use Retumbo powder because, well I just want to, and I have a #### load of Retumbo. You have some information that you can run the bullet 2350 ft/s and by george she's agona run 2350 ft/s, hell or high water.

IF

You took a scientific approach to knocking down those high mountain elephants you would realize that your dream was just that. But the 375 RUM is quite capable in its standard/common loadings but I'll give you that Mt Elephant might tax its ability. In many industries modeling has taken the place of over-engineering and trail and error to produce a product or end result.

My handloading hobby has spanned over 4 decades and with the availability of an accurate velocity measuring device, Quickload (internal ballistics), and external ballistic programs. My loads are safer and more accurate than anytime before. And , the bonus here less resource spent on load development and more time slamming steel and drilling X rings.

I have many first hand samples of this that I can discuss with you. However, that won't be until next week as we are off to the Kootenays, hopefully there is time to check for Mt Elephant sign.

Have a great week.
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Enjoy your trip, nice country to travel through. Actually I wasn't looking specifically for a mountain elephant loads, although we did see in excess of 300 Elephants while hunting in the Selous, but they were far outside of my pay scale. African buffalo was the critter of interest on that adventure. Just so you know for future consideration, since you seem preoccupied with that species, an elephant is best handled with a solid that typically penetrates in excess of 4 feet of dense heavy tissue and bone, rather than a soft point that penetrates only 32". For the solid to perform well, that is to follow a straight line of penetration without wandering off towards the path of least resistance, short bullet length, parallel sides, and a flat or hemispherical nose combined with high impact velocity provides the best penetration. Speer's old African Grand Slam made with a tungsten core resulted in a short .375-300 gr bullet, that worked exceptionally well not only on heavy game, but light game like impala and wart hog as well. At home my requirements are more pedestrian, but the 380 Rhino might someday get a workout on a Yukon bison.

In the meantime . . .
 
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Quickload is a model. Its a good guess. If the model tells you to keep going and the gun is telling you to quit do you keep going?

Manuals are a measurement in one barrel and a good guess in another. If the manual says keep going and the gun says quit, do you keep going?

Chronographs take a measurement and a good guess at pressures. If the chronograph says "pour the #### to 'er" and the gun says "get a helmet" do you up the charge? If you are getting more than any right thinking person would expect do you grin and think you invented free velocity?

Ditto for casehead measurements.

Likewise for ejector marks, or sticky bolt lift. Oh, it wasn't that bad or thaaaat sticky? Should you keep going?

If you hitch your star to any one indicator or system to the exclusion of all others you are going to get burned sooner or later assuming you shoot enough. Luckily, there is a lot of safety margin built into a rifle and if you don't get off scotch free you will probably live through it. Good chance you don't even get hurt, slight chance of getting dead. Maimed is somewhere in between. ;)

View the process as a whole, and if something is telling you to quit its best to listen even if your favorite is saying the opposite.
 
Dogleg said:
Quickload is a model. Its a good guess. If the model tells you to keep going and the gun is telling you to quit do you keep going?

Manuals are a measurement in one barrel and a good guess in another. If the manual says keep going and the gun says quit, do you keep going?

Chronographs take a measurement and a good guess at pressures. If the chronograph says "pour the #### to 'er" and the gun says "get a helmet" do you up the charge? If you are getting more than any right thinking person would expect do you grin and think you invented free velocity?

Ditto for casehead measurements.

Likewise for ejector marks, or sticky bolt lift. Oh, it wasn't that bad or thaaaat sticky? Should you keep going?

If you hitch your star to any one indicator or system to the exclusion of all others you are going to get burned sooner or later assuming you shoot enough. Luckily, there is a lot of safety margin built into a rifle and if you don't get off scotch free you will probably live through it. Good chance you don't even get hurt, slight chance of getting dead. Maimed is somewhere in between. ;)

View the process as a whole, and if something is telling you to quit its best to listen even if your favorite is saying the opposite.
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Excellent advice as always!
 
they are, Mike. 25 licenses and only 60 applicants this year.

h t t p ://www.env.gov.yk.ca/hunting-fishing-trapping/bisonhunt.php
h t t p ://www.env.gov.yk.ca/hunting-fishing-trapping/special-guide-licence.php

i do not know for fall season, i know that BUM took in NWT, in the fall one, but always heard about winter hunts over here. but it can be done as it s in season open.

so far the last winters were not really winter and it was hard for some to haul meat on feet on long distance as snow was not around.
 
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