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:: PRESSURE, VELOCITY AND THE 444 MARLIN by Bill McConnell
Thanks and God Bless,
:: PRESSURE, VELOCITY AND THE 444 MARLIN by Bill McConnell
Thanks and God Bless,
Pressure, Velocity And The 444 Marlin
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Thanks for the kind words Mike! It was a lot of work but mostly a labor of love to learn these things. I have taken the same path with my H&R single shot 44 mag (22" bbl"). Though the work was not nearly so exhaustive, I ended up with a similar understanding of how the 44 mag responds to pressure. I took much of what Marshall has taught me and ended up with safe & sane loads that actually start to intrude on the 444. With modest Redhawk pressures, I got 1850 fps out of Marshall's 290gr bullet, 1950 fps out of his 265gr bullet and 1700 fps out of his 325gr LCMN bullet. These giving at or near moa accuracy out to 200 yards. There is a lot more but it's a hoot to make these things work.
Bill
Bill
A few Questions?
I read with great interest this particular Tech Note, and as an engineer (and admitted nit-picker), I've got a few questions.
In your tables you refer to CHE as "case head expansion". The numbers posted seem EXTREME to me, unless you really mean "case head diameter". There's no way that these cases are expanding this much without rupturing. Actual case head expansion would be these measurements minus the original measurement, would it not? So in reality, aren't these numbers the actual case head measurements? I'm reasonably sure that you have the actual before and after measurements, so you should be able to present the actual expansion numbers. And wouldn't that be a more accurate assessment of the pressures? Might give you the same overall results, but then again maybe not.
Also, in your table of the larger bullets, I think there's a typo in the CHE column for the 330 gr/50 gr. H-322 row. Is that really 0.4995, or should it be 0.4695? Which draws me to the last question, concerning the "twist" you mentioned. I don't see how 0.4995 (or even 0.4695) is the same as 0.4682, so I don't see how the pressures are the same.
Maybe I'm missing something in my interpretatin of the data. Please don't take this as an attack on your work - I really think it's a fabulous piece of work! I love this kind of serious analysis and wish I had the time to do it myself. Feel free to PM me if you'd like to discuss this that way.
I read with great interest this particular Tech Note, and as an engineer (and admitted nit-picker), I've got a few questions.
In your tables you refer to CHE as "case head expansion". The numbers posted seem EXTREME to me, unless you really mean "case head diameter". There's no way that these cases are expanding this much without rupturing. Actual case head expansion would be these measurements minus the original measurement, would it not? So in reality, aren't these numbers the actual case head measurements? I'm reasonably sure that you have the actual before and after measurements, so you should be able to present the actual expansion numbers. And wouldn't that be a more accurate assessment of the pressures? Might give you the same overall results, but then again maybe not.
Also, in your table of the larger bullets, I think there's a typo in the CHE column for the 330 gr/50 gr. H-322 row. Is that really 0.4995, or should it be 0.4695? Which draws me to the last question, concerning the "twist" you mentioned. I don't see how 0.4995 (or even 0.4695) is the same as 0.4682, so I don't see how the pressures are the same.
Maybe I'm missing something in my interpretatin of the data. Please don't take this as an attack on your work - I really think it's a fabulous piece of work! I love this kind of serious analysis and wish I had the time to do it myself. Feel free to PM me if you'd like to discuss this that way.
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Hi Doug,
Thank you for your questions.
Your question of case head expansion is explained in the text of my article. Still, it could be described as the final expansion diameter of the case head. I know people use different methods of measuring the case head to estimate pressure. The method I described in my article does not require any before dimensions at all as long as all the "rules" are followed. Personally, I have never understood the advantage of understanding the before dimensions when that number is subject to so many variables.
Yes, you found a typo I missed. The .4995 should have read .4695.
Doug, you wrote, "Which draws me to the last question, concerning the "twist" you mentioned. I don't see how 0.4995 (or even 0.4695) is the same as 0.4682, so I don't see how the pressures are the same."
It is , .4695 of course. What I was referring to in the article is that there were no signs of a change in pressure based on the typical empirical ways of looking at the primers or testing for extraction problems. Without the micrometers, these vastly different loads appeared to have the same pressure when there was actually quite a difference.
I hope this helps Doug. I appreciate your interest.
Bill McConnell
Thank you for your questions.
Your question of case head expansion is explained in the text of my article. Still, it could be described as the final expansion diameter of the case head. I know people use different methods of measuring the case head to estimate pressure. The method I described in my article does not require any before dimensions at all as long as all the "rules" are followed. Personally, I have never understood the advantage of understanding the before dimensions when that number is subject to so many variables.
Yes, you found a typo I missed. The .4995 should have read .4695.
Doug, you wrote, "Which draws me to the last question, concerning the "twist" you mentioned. I don't see how 0.4995 (or even 0.4695) is the same as 0.4682, so I don't see how the pressures are the same."
It is , .4695 of course. What I was referring to in the article is that there were no signs of a change in pressure based on the typical empirical ways of looking at the primers or testing for extraction problems. Without the micrometers, these vastly different loads appeared to have the same pressure when there was actually quite a difference.
I hope this helps Doug. I appreciate your interest.
Bill McConnell
44 Mag Loads In H&R Single?
Bill, are you planning another article on the 44 Mag loads in the H&R single shot, or can you share it now? It would be very interesting to compare with the data James Gates is working up on the 44 Mag Max & 265gr. The 1950fps with the 265gr is impressive, not to mention the MOA @ 200 yards!
TIA!
Bill M said:
Bill, are you planning another article on the 44 Mag loads in the H&R single shot, or can you share it now? It would be very interesting to compare with the data James Gates is working up on the 44 Mag Max & 265gr. The 1950fps with the 265gr is impressive, not to mention the MOA @ 200 yards!
TIA!
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Hi Gowge,
Yeah, I'd be happy to put together a tech notes on my pressure/velocity work with the 44 mag. That is, if it's ok with Marshall.
Right now though I can give you at least some perspective on my high end work with the 44 mag and with my understanding of James Gates work with the 44 Max. (James, feel free to correct me here).
The high end of velocities I get with the 44 mag (bullets seated out as far as the H&R rifle will allow) is still below the 44 Max. I can't prove it but I think the 44 Max is running less pressure than my high end (Redhawk pressures) loads. The 44 Max is certainly a more flexible rifle cartridge the the 44 mag. It might be fair to say that the absolute top of what can be done with the 44 mag in a rifle roughly touches the bottom of what the 44 Max can do. I suppose there is a similar relationship between the 44 Max and the 444 Marlin. I believe James work with the 44 Max is with shorter barrels than my 22" H&R.
You should also note that my loads will not cycle thru an 1894 lever action. The 44 Max was designed to work in 336 lever actions as well as single shots. The accuracy issue is typically because the single show H&R's often shoot great. All my tested loads were very accurate save but one (and that bullet when seated back in the crimping groove with the right amount of powder was the most accurate load of all). Expect the 44 Max to be a moa cartridge in the right rifle.
Hope this helps a bit for now. By the way, I am getting a 44 Max next year.
Best........... Bill
Yeah, I'd be happy to put together a tech notes on my pressure/velocity work with the 44 mag. That is, if it's ok with Marshall.
Right now though I can give you at least some perspective on my high end work with the 44 mag and with my understanding of James Gates work with the 44 Max. (James, feel free to correct me here).
The high end of velocities I get with the 44 mag (bullets seated out as far as the H&R rifle will allow) is still below the 44 Max. I can't prove it but I think the 44 Max is running less pressure than my high end (Redhawk pressures) loads. The 44 Max is certainly a more flexible rifle cartridge the the 44 mag. It might be fair to say that the absolute top of what can be done with the 44 mag in a rifle roughly touches the bottom of what the 44 Max can do. I suppose there is a similar relationship between the 44 Max and the 444 Marlin. I believe James work with the 44 Max is with shorter barrels than my 22" H&R.
You should also note that my loads will not cycle thru an 1894 lever action. The 44 Max was designed to work in 336 lever actions as well as single shots. The accuracy issue is typically because the single show H&R's often shoot great. All my tested loads were very accurate save but one (and that bullet when seated back in the crimping groove with the right amount of powder was the most accurate load of all). Expect the 44 Max to be a moa cartridge in the right rifle.
Hope this helps a bit for now. By the way, I am getting a 44 Max next year.
Best........... Bill
Thanks Bill
Thanks Bill! Yea, I think James is 'bout ready to test the H&R that's been re-chambered to the Mag Max, and the comparison is gonna' be most interesting. That conversion or re-chambering job has gotta' be EASY on a lil' single shot.
Thanks again!
Gowge
Bill M said:
Thanks Bill! Yea, I think James is 'bout ready to test the H&R that's been re-chambered to the Mag Max, and the comparison is gonna' be most interesting. That conversion or re-chambering job has gotta' be EASY on a lil' single shot.
Thanks again!
Gowge
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Hi Contender,
You ask a real good question about the throat on a Handi Rifle. It does not look like a throat in the sense of a bottle necked cartridge throat. I know they can be "throated" or free bored to allow for the increased length of a bullet out of the case. Maybe sombody else has more throating experience in single shots.
Bill
You ask a real good question about the throat on a Handi Rifle. It does not look like a throat in the sense of a bottle necked cartridge throat. I know they can be "throated" or free bored to allow for the increased length of a bullet out of the case. Maybe sombody else has more throating experience in single shots.
Bill
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