Zip files for dummies?

[finnbear270]

What am I doing wrong?, Gordon's reloading tool, followed instructions but get no further than registration.
Getting really peeed off with trying to get any hints on some stuff, but even worse now having hit the buffers with this.

 

[finnbear270]

Anyone know if a 16GB Flash drive has enough space to take the files needed?

 

[Mike L]

What size is the zip file?, Also some usb drives need formatting before transfer

 

[charlieboy-shooter]

Hi,

Yes should be. GRT is 295MB ( 16GB - 16000 MB)

 

[zambezi]

Once registered, you have to log in [right side of webpage]before the download page becomes accessible. Per image below. Apols if this bit is obvious and I am misunderstanding where the trip up is for you.

 

[finnbear270]

After several download failures at different points, I have wrestled the internet down & have secured the files onto my USB. Just firtling with it at the mo'

 

[zambezi]

As discussed, GRT seems to do a great job of most things. However, the MV prediction was a little off for some stuff I tested. Including 6.5PRC.

What I suspect is that perhaps one or other of my data inputs is a tad off, and that is unseating the app's maths.

Certainly I trust the Magnetospeed's empirical measurement as its declaration of factory ammo MV was utterly validated by drop data on a 600yd range, 50 rounds.

 

[borbal]

Zambezi, the Barnes TTSX bullets are monolithics and so are more difficult to deform than regular cup-and-core bullets. See if you can unlock the bullet resistance and put it up to two or three times what is currently is. And you could try increasing your initial pressure by 50% as well. You should get in the ballpark then.

 

[zambezi]

Zambezi, the Barnes TTSX bullets are monolithics and so are more difficult to deform than regular cup-and-core bullets. See if you can unlock the bullet resistance and put it up to two or three times what is currently is. And you could try increasing your initial pressure by 50% as well. You should get in the ballpark then.

borbal, I tweaked both bullet hardness and initial pressure through a huge range on the GRT interface and MV changed marginally.

Even when I apply my load data to other online apps [which make specific provision for harder monometal projectiles] the MV calculation comes up shy of real-world measurement:

 

[borbal]

Well Zambezi, as with any precision, complex tool, it pays to read the instructions. See that little asterisk by the term "Powder space*" on the front page of P-Max? If you look down the page to see what that asterisk refers to, it reads, "*Powder space is the capacity in the case behind the loaded bullet." You put in the case capacity to overflowing....

If you run the "expert" version of GRT, it will give you the "combustion chamber" which is the same thing as "Powder Space" in P-Max. Running GRT with your load I get a Powder Space of 61.3 grains of water.

You also put in 49 grains of powder, instead of 50 grains, which you entered into GRT in your post above, and which is declared by your measured muzzle velocities.

Making these adjustments to the inputs in P-Max, I get a much more realistic muzzle velocity.

This is still 150 ft/sec. short of what you measure, but despite your statement above, I recall you have admitted in the past that your Magnetospeed is a shade optimistic...?

And of course, this is an estimated Powder Space. You should measure it yourself to ensure you are using good data.

 

[zambezi]

Powder space is the capacity in the case behind the loaded bullet. You put in the case capacity to overflowing

That is the usual definition of case volume. Indeed GRT makes that statement explicitly. And I did measure it. And in expert mode it is clear that it has deduced the combustion chamber volume appropriately. But still underestimates MV...







I did not see that Pmax sought "powder space" rather than "case volume". mea culpa. And the 49gr powder charge was a cut-n-paste error from an earlier work-up. But even with 50gr of powder as the measure, the Pmax powder space has to drop to 56gr before the MV marries. I will measure that next but strongly suspect the GRT figure is close.

So your last point is the possibility that the Magnetospeed is over-reading. As I say, the 600yd range day in which I sent 50+ rounds down says it is pretty accurate: 40 clicks on 1/4moa scope where rifle was first zero'd at 100m, tested again at 182m, 274m.

Thank you for clarity on the Pmax data requirement re "powder space". That is really good to know.