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Posted: 2/3/2013 7:17:15 AM EDT
| Yesterday I took my NM AR15 out loaded up with 23gr. IMR 4895, 75 gr Hornady BTHP, CCI 41 primer , LC brass and a 2.25 OAL. The shots had excellent results at 200, 300, 400 and 500 yards. At 600 yards the shots scattered. Any suggestions on how to tweek this load or an alternative load. Thanks. |
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Quoted:
Two possible causes of instability come to mind . . . first, the projectile simply lost it at that range, or it actually fell slow enough to go subsonic. Were it me, I'd try to speed up the round for 600 yard use. This. Get a chrono and figure out exactly what speed you're cooking, then plug it into a ballistics program and see what you get. That will tell you the effective limits of your round. |
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Quoted:
Quoted:
Two possible causes of instability come to mind . . . first, the projectile simply lost it at that range, or it actually fell slow enough to go subsonic. Were it me, I'd try to speed up the round for 600 yard use. This. Get a chrono and figure out exactly what speed you're cooking, then plug it into a ballistics program and see what you get. That will tell you the effective limits of your round. Better yet chrono at 15 feet and 500 yds and let us know if the ballistics program works. |
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Quoted:
Quoted:
Quoted:
Two possible causes of instability come to mind . . . first, the projectile simply lost it at that range, or it actually fell slow enough to go subsonic. Were it me, I'd try to speed up the round for 600 yard use. This. Get a chrono and figure out exactly what speed you're cooking, then plug it into a ballistics program and see what you get. That will tell you the effective limits of your round. Better yet chrono at 15 feet and 500 yds and let us know if the ballistics program works. If you are accurate enough to chrono your loads at 500 yards, I'd put that in the pretty amazing category. I've seen chronos get shot at 15-20 feet, so shooting at one at that distance would certainly take big brass ones. Unless you are independently wealthy, and have a stockpile of them. In which case, can I get an invite to your next range session? 
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Quoted:
Quoted:
Quoted:
Quoted:
Two possible causes of instability come to mind . . . first, the projectile simply lost it at that range, or it actually fell slow enough to go subsonic. Were it me, I'd try to speed up the round for 600 yard use. This. Get a chrono and figure out exactly what speed you're cooking, then plug it into a ballistics program and see what you get. That will tell you the effective limits of your round. Better yet chrono at 15 feet and 500 yds and let us know if the ballistics program works. If you are accurate enough to chrono your loads at 500 yards, I'd put that in the pretty amazing category. I've seen chronos get shot at 15-20 feet, so shooting at one at that distance would certainly take big brass ones. Unless you are independently wealthy, and have a stockpile of them. In which case, can I get an invite to your next range session? I have to agree with this. If you try to chrono at 500 yds, I want to see it. 
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Last fall I watch some black powder cartridge shooters set up a chronograph at 100 yards to get velocity so they could do some long range drop calculations. First they verified the rifles where hitting where aimed and this with peep sights. When they set up the chronograph, they had a big piece of steel plate they put in front of the screens so that if a shot was low, it would hit the plate instead of the chronograph.
Don't know how well it would have worked as they never shot low enough to hit the plate. Guess it you have enough confidence in your shooting you can do it. |
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I'd be comfortable chronoing my Ar15 or Sako from the bench at 100 yards. I'd still want to put that steel plate in front of the sensors though. Under those conditions, I think a lot of us would . . . at least on a calm day lol.
500 yards may give you better data, but its data I'll never have lol. |
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