ESTIMATING MV

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  • Last Post 04 August 2018
joeb33050 posted this 04 August 2018

We've got  MV for 2 bullets (40 and 55 gr)and 2 powder charges, (7 and 8.5 gr) for a certain barrel, (Shilen 22-250).

We know that MV and powder charge are linear from 5.5 to 8.5 gr., so we can easily estimate MV for all charges from 5.5-8.5 gr.

We know that MV varies .8% / inch of barrel length, sdo we can easily estimate MV for any barrel length.         We know that the slope of MV vs. case volume varies, as does MV; so we can easily estimate MV for any cartridge case.

We know that the slope of MV vs powder charge varies with bullet weight, so we can easily estimate MV for any bullet, cartridge, and  powder charge  from 5.5-8.5 gr. Titegroup. ANY!                                     

 

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Ken Campbell Iowa posted this 04 August 2018

probably ... somewhere in my stash i have a slide-rule type POWLEY estimator ... seemed to work ok ....  it did kinda a similar thing .....   also, after 50 years i have a spot in my brain that can extrapolate pretty good for plinking loads ... and yes, i use the " logic " .. well it's case bigger than a 222 but smaller than a 308 ..., but a tighter barrel, and hotter powder than blue dot so 6 grains of Trap 100 will get me about 1100 fps ... " ...  load'em and shoot'em ...

ken

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