Author Topic: Pocket Remington and Navy Yank snub chrono session.  (Read 4968 times)

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Offline G Dog

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #15 on: January 26, 2017, 09:30:13 PM »
That’s a first class range report, really well done.  Very interesting results.  Thanks, N.E.

I use this formula:

E=   m V² /  64.32      Where m = grains/7000

Same as Omni’s,  just different. 
"For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places".   
                                        Ephesians 6:12  (KJV)

Offline necessaryevil

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #16 on: January 27, 2017, 03:04:42 AM »
That’s a first class range report, really well done.  Very interesting results.  Thanks, N.E.

I use this formula:

E=   m V² /  64.32      Where m = grains/7000

Same as Omni’s,  just different.

Thank you, same but different. I like it.

Offline Omnivore

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #17 on: January 27, 2017, 11:39:25 AM »
To be exactly the same but different, G Dog's conversion number at the end would have to be 64.34, wouldn't it?  I don't think it'll change your results significantly either way though.

Grams, meters per second and Joules make more sense, but we've grown up with foot pounds and such, so we have to use a conversion based on Earth's gravitational acceleration (one foot pound being the energy required to raise one pound by one foot **under Earth's gravity**).  The foot pound then is not only Earth-centric, it can't be defined precisely without getting together and agreeing on a standard number for Earth gravity (it's not exactly the same everywhere you go on the planet's surface).

Jdurand; think of the X Frame 500 as carbine power in pistol form.  Its ballistics are comparable to the 405 Winchester, 45-70, 444 Marlin and other "big bore" lever action setups.  I know a guy who hunts with one.  You can carry it in a chest rig with both hands free, and nothing protruding to snag on things in the environment.  With a 10" barrel and a scope, its recoil is not bad at all with 300 grain FTX bullets, and a good shooter can take big game with it at reasonable lever action carbine distances.  It has it's place, thoughbeit a somewhat specialized one.  As a "counter insurgency weapon" you might say it would be well suited in that it puts a lot of horsepower into a somewhat concealable form.  Yes it is loud, but so is any mid power centerfire rifle.  Ever sit next to someone shooting a braked 7mm Magnum or 300 Magnum?
But whoso looketh into the perfect law of liberty, and continueth therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed.   James 1:25 (KJV)

So speak ye, and so do, as they that shall be judged by the law of liberty.   James 2:12. (KJV)

Offline G Dog

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #18 on: January 27, 2017, 02:16:54 PM »
To be exactly the same but different, G Dog's conversion number at the end would have to be 64.34, wouldn't it? 
 

You’re quite right Omni, good catch and my bad. 

450400/7000 = 64.34(285714285714)

Accordingly (for the record then and to be like your formula, only different) the correct expression is:

E = m V² /  64.34      Where m = grains/7000

Yours, E = grains x V² /  450400 is more direct and easier.  I use the one above cause the standard cheepo calculator usually at hand here won’t handle the amount of digits for m (in actual, unconverted grains) times V².



« Last Edit: January 27, 2017, 02:37:21 PM by G Dog »
"For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places".   
                                        Ephesians 6:12  (KJV)

Offline Phil97

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #19 on: January 24, 2018, 05:09:54 PM »
Wow, I did not expect so much energy out of the snubnose. usually these guns need long barrels to make use of the slower burn rate of black powder. Perhaps 777, being a substitute burns differently?

Offline necessaryevil

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #20 on: January 27, 2018, 09:07:22 AM »
Wow, I did not expect so much energy out of the snubnose. usually these guns need long barrels to make use of the slower burn rate of black powder. Perhaps 777, being a substitute burns differently?

Neither was I to be honest. But the numbers were definitely correct. The reason why I know is that first we did a benchmark test with the Norinco M93 with the standard .22lr CCI ammo for which we already knew the given velocity of. So the chrono was accurate. A pleasant surprise I must say.

Offline WECSOG

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #21 on: January 27, 2018, 08:12:58 PM »
To be exactly the same but different, G Dog's conversion number at the end would have to be 64.34, wouldn't it? 
 

You’re quite right Omni, good catch and my bad. 

450400/7000 = 64.34(285714285714)

Accordingly (for the record then and to be like your formula, only different) the correct expression is:

E = m V² /  64.34      Where m = grains/7000

Yours, E = grains x V² /  450400 is more direct and easier.  I use the one above cause the standard cheepo calculator usually at hand here won’t handle the amount of digits for m (in actual, unconverted grains) times V².
I have a shortcut that I usually use: first divide velocity by 100. That's easy to do in your head; 874 fps becomes 8.74. 2700 fps would be 27. Anyway you square that number, multiply by mass in grains, and divide by 45. So a 48 grain bullet at 874 fps would be 8.74^2 * 48 / 45 for 81.48 fpe. Doesn't come out exactly the same, but I think we can safely ignore one 100th of a percent error. Especially since 1 fps deviation would change the result by more than twice as much, just to put it in perspective.

Offline Phil97

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #22 on: April 27, 2018, 10:26:00 PM »
necessaryevil I saw that you posted results for the .31 in a previous thread and the average was much lower. What do you think caused the higher velocities in this test? Did you compress the powder more?

Offline necessaryevil

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #23 on: April 28, 2018, 02:16:07 AM »
Phil,

The first chrono test was done with 11 grains of T7.

If you notice on the second more organised session I managed to SQUEEZE 11.5 grains of T7 into the .31 chambers. I load off the gun with the cylinder on a brass stud and seat the .322" balls with a brass drift and a plastic hammer.

So yes I would suggest that the higher numbers are due to an extra half grain of powder that would have to be more tightly compressed.

Offline Phil97

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Re: Pocket Remington and Navy Yank snub chrono session.
« Reply #24 on: April 28, 2018, 05:23:34 AM »
Thanks for the reply. I would have never imagined that half a grain of 777 would have made such a difference, despite the compression