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Old 10-13-2012, 06:14   #29
Big Bird
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Quote:
Originally Posted by Travclem View Post
Do you know by how much it changes the distance? Really too late now, I ordered the 16".


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If you take a standard Federal Gold Medal Match load with the 175 grain bullet you will see a muzzle velocity of around 2650 fps with a 20" barrel. Trim it back to 16" and you are looking at about 2450 (I disagree with the 100 fps loss per inch--its more like 50 fps in my experience).

If you really want an eye opener look up the numbers for a Sierra 168 Gold Medal Match load and make the velocity adjustment for the shorter barrel and look where it goes sub-sonic. I can't tell you how many times I've seen people try to shoot that load at 1,000 yards with a short barrel gun and have been in the pits and have seen the bullets keyhole. I've had more than a few people here tell me I'm full of crap when I say this. But the ballistics calculator doesn't lie. Run the numbers for yourself. The 168 grain bullet is a crappy long range bullet for different reasons as well. But the retained velocity of this bullet out of a short barrel is pitiful.

Run the above numbers through any ballistics calculator and you will see that the 20" barrel keeps the 175 grain supersonic well out to ~1100 yards while the 16" barrel will be dropping below the supersonic barrier at ~1,000 yards. That's at sea level.

At 500 and beyond its the wind that gets you though and velocity matters in the wind. Its not the wind you can dope that gets you. (providing you can dope wind) Its the wind that you can't predict. I've personally used windage corrections at 1,000 yards that involved 30 quarter MOA clicks of applied windage--that's more than 7 feet of wind drift... If a small gust catches you bullet it will blow it 9-10 inches at 1,000. Again, velocity matters--and I should rephrase that to; RETAINED velocity matters most. Muzzle velocity is largely irrelevant except that it contributes to retained velocity downrange.

I'm unimpressed with people who tell me things like I've seen people make hits with a given platform at 1,000 yards etc. How many shots did it take to make a hit? Under what conditions? Known distance range? Sighters? Hell, if I throw enough lead downrange with my Colt Single Action I'm quite certain I can make hits at 500 yards...
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Last edited by Big Bird; 10-13-2012 at 06:57..
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