speed question

rhino519

rhino519

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im reloading .243 Win for my savage 11, and trying to put in info into ballistic calculator when i realized that the speeds published in the book will not reflect the ones achieved by my rifle

the load im after is 44.5 of H4895 under 55 grain varmageddon bullet, the speers book says it will achieve speed of 3900 ft/sec (from my memory) shooting oiut of a 24in lilja barrel,
now my rifle has a sporter 21in barrel, anyway i can calculate the speed difference so that my calculations on dope card will reflect it?


i know chronograph would solve this easy, i just dont have $ to get one.
 
Just because the reloading manual says it will get 3900ft/sec with a 24 inch barrel doesn't mean every gun with a 24 inch barrel will get that speed. Even if you could calculate the difference between a 24 inch and 21 inch barrel the results would not be accurate anyway.
 
I think its around 25fps per inch, somewhere around there, but like others have said its NOT 100% accurate.

If you dont have something to measure it with. Just shoot in at 200, 400 & 600 yds or something like that and get the actual measurement. After that play around with the numbers in you app so that it matches up.
 
Get a ballistic calculator with a trueing feature.
Input all rifle data and ammo data. it's ok to estimate velocity if you don't own a chrono.

Zero at an accurate known distance.
Just because your range says 100 Yards or Meters doesn't mean it is.
Input all environmental data possible.

Now shoot at a known max distance using your calculated data.

As an example if you are now shooting at 500Y and your calculator says 12 MOA dial 12 MOA and see where it hits.
If your actual elevation is 11.25 MOA you will input that data into the trueing feature and it will correct your velocity and bullet drop for all distances.

The most important thing is that you must keep on top of all environmental factors.
I use a topographical map or Google earth for accurate elevation and I check temperature and barometric pressure frequently.
 
The truth is it won't make a pinch of coon's spit worth of difference out to 400 mtrs..........load 'em up, sight her right on the mark at 300 mtrs and go kill stuff. All the rest is just ballistic masturbation..........get to know your rifle and load, velocity is irrelevant within the first 400 mtrs between 3600 fps and 3900 fps don't even worry about it..........
 
may have caught a bug of precision shootin' and thinking of putting a buullit behind an ear of groundhog at 600m, alas you right c- nothin' replaces experience and it's hood therapy for them bugs
 
The only answer is a Chronograph. I've seen an 06 with a 20" barrel shoot the same loads 100 fps faster tan another rifle wih 22". There are so many other variables that it is hard to predict the end result.
 
c-fbmi said:
The truth is it won't make a pinch of coon's spit worth of difference out to 400 mtrs..........load 'em up, sight her right on the mark at 300 mtrs and go kill stuff. All the rest is just ballistic masturbation..........get to know your rifle and load, velocity is irrelevant within the first 400 mtrs between 3600 fps and 3900 fps don't even worry about it..........
Click to expand...


Now Douglas, you're into my jargon. Ever since I was knee high to a grass hopper my favourite expression to describe something that was completely useless, was to say it wasn't worth a pinch of coon manure!
Anyway, we each have the same opinion of a ballistic calculator.
Bruce
 
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