No Chrony, Help Please

casterpollox

casterpollox

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I'm stumped. I searched the forum but came up empty so I'm asking for some help.

I'm reloading 300wsm and I'm trying to find my velocity to use in the ballistic calculator. Only problem is that the published velocities I found are for longer barrels. I have a 20 inch barrel and no chronograph.

Is there a program that can give me a ball park estimate? Does some one have one that can run the numbers for me please?

Thanks in advance.
 
Shoot some groups at 100 and 200yds (even better if you can do it at 300yds as well), plug in your bullet data and estimated MV into a ballistics calculator and then tweak the velocity until the predicted trajectory closely matches your measured one. Make sure you get all the measured data as accurate as you can, in order to make velocity the only unknown variable.

If you want a really rough rule of thumb, figure on around 40-50fps loss per inch of barrel.

Mark
 
Just deduct approx.50 to 75 fps for every " your shorter than the published data.If say you have a 24" load at 3000 fps your 20" should be close to 2800 fps.Now don't flame me I did say approx.I used this with my 25-06 with a 22" compared to a 24" load data and I was lossing 65 fps.
 
mmattockx said:
Shoot some groups at 100 and 200yds (even better if you can do it at 300yds as well), plug in your bullet data and estimated MV into a ballistics calculator and then tweak the velocity until the predicted trajectory closely matches your measured one. Make sure you get all the measured data as accurate as you can, in order to make velocity the only unknown variable.

If you want a really rough rule of thumb, figure on around 40-50fps loss per inch of barrel.

Mark
Click to expand...

OOPS. I should have read your post first and saved all my typing.
 
casterpollox said:
I'm stumped. I searched the forum but came up empty so I'm asking for some help.

I'm reloading 300wsm and I'm trying to find my velocity to use in the ballistic calculator. Only problem is that the published velocities I found are for longer barrels. I have a 20 inch barrel and no chronograph.

Is there a program that can give me a ball park estimate? Does some one have one that can run the numbers for me please?

Thanks in advance.
Click to expand...

PM your load info and I will run it through Quickload.

Need cartridge type, powder type and charge, bullet weight and type, Cartridge OAL, barrel length , length of bullet, H2O capacity of case would help but is not necessary.
 
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