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04-07-2016, 07:50 PM
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There are two requirements for barrel length:
1) Long enough to stabilize the bullet
2) Long enough to develop the minimum required velocity for the powder in use.
The shortest barrel that will accomplish the above is the one to use. The sooner the bullet leaves the barrel, the better.
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04-07-2016, 09:50 PM
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Quote:
Originally Posted by R. G. Amos
The sooner the bullet leaves the barrel, the better.
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This is an interesting statement and contrary to much of what I've read. Would you care to expound on that a little?
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04-09-2016, 08:57 AM
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You are making great progress. Another way to tighten your groups is to work on the consistency of your ammo. If you have a chronograph, you want to work on getting the SD to under 15 fps for a 5-10 shot group. Mathematically, the closer your SD is to zero, the tighter your groups should be.
Also, don't get distracted by the horizontal dispersion of your group, focus on the vertical dispersion ... it will provide a better indicator of ammunition consistency and accuracy.
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04-09-2016, 09:23 AM
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Looks like you're doing pretty well to me.
Sent from my iPhone using Tapatalk
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04-09-2016, 07:25 PM
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Looking forward to seeing the 500 yard groups!
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05-12-2016, 01:07 AM
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05-12-2016, 01:33 AM
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Good job, rastoff! I went down this road years ago w an m1a. Then went to a custom built 308. Then to a milspec 5r in 308. 8" at 1000 yds 3 seperate times.
I have a DPMS LR in 308 that I will hopefully get to play with out to 800, someday.
LRrifleman is spot-on with his advice. BTW, you need 2700 + MV with a SIERRA 175 MK to stay supersonic at 1000 yds. I used to shoot at the FOLSOM range many years ago.
Enjoy the journey!
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05-17-2016, 01:07 AM
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Finally got to shoot some longer targets. We went out to the desert and set up this range:
See the two white dots indicated by the arrow? Yeah, they're 600 yards away. That's a long shot.
We started at 200 and I had some trouble with my zero. I had previously zeroed my gun at 200 yards, but it was way off this day. I was using the same ammo as when I zeroed it. I don't know what was wrong, but it will require some more research.
Anyway, we then went to 400 yards and I put up this group:
A little high and to the left, but a decent group for my first shots ever at 400 yards.
When we got to 600 I was off the paper to the left. My buddy put up a .7MOA group though. All in all it was a good day. I have a lot to learn and am looking forward to the journey.
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05-17-2016, 09:19 AM
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Great shots, both photographic and gun-wise!
Your 400 yard group looks promising with a 0.4 (+/-) MOA vertical group dispersion. Figure that the 1 minute horizontal dispersion is due to an approximate 5 mph wind. Once your group is centered, you are looking at X ring accuracy.
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05-17-2016, 08:19 PM
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Yes, I think on the 400 yard target I didn't dial in any wind correction. At 600 I did dial in .3mil of wind correction, but it wasn't enough.
We didn't have an anemometer. We guessed at the wind, but I don't think I got it right.
It's all part of the learning process. Dealing with wind and the mirage was new to me. I don't know how or if I need to correct for the mirage.
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05-17-2016, 09:13 PM
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I've been told that shooting early is the best way to eliminate mirage. Outside of dumping some serious cash on a top notch optic. A sun shade is supposed to help some but I think that is more for glare and heat off the barrel than for mirage.
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12-20-2016, 04:45 AM
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Wind at your firing point is not usually the same as the wind downrange.
Folsom range is crazy like that.
The best you can do is read the mirage. But that doesn't tell you what the wind is doing at the height of your trajectory.
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