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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5002 Location: NC foothills
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Posted: Sat Jul 30, 2016 1:59 pm Post subject: Negative sight heights? |
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I have a laser under the bore of one of my guns so I tried to enter a negative sight height to see what the trajectory might be. Didn't work, it automatically corrected it to a positive number. I'm not sure how many of us would use this feature but I thought I'd throw it out there.
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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PaulS Super Member
Joined: Feb 18, 2006 Posts: 4330 Location: South-Eastern Washington - the State
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Posted: Sat Jul 30, 2016 5:32 pm Post subject: Re: Negative sight heights? |
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There is always one guy doing something the programmer never thought would come up...
Nice going Pumpkinslinger!
(if I had written the software it would have crashed, out of spite.
_________________ Paul
__________________
Speer, Lyman, Hodgdon, Sierra, and Hornady = reliable loading data
So and So's pages on the internet = NOT reliable loading data
Always check data against manuals
NEVER exceed maximum listed loads |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5002 Location: NC foothills
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Posted: Sat Jul 30, 2016 5:37 pm Post subject: Re: Negative sight heights? |
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I try Paul!
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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Elvis Super Member
Joined: Jul 27, 2008 Posts: 9253 Location: south island New Zealand
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Posted: Sat Jul 30, 2016 6:11 pm Post subject: Re: Negative sight heights? |
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Pumpkin......... you can use that as a rangefinder of sorts. if you get lazer to intersect with cross hairs at a known distance,,,say 100 yards if beam/dot is below crosshair so is range and vice versa...works a treat on rifles.
as to your issue.......beats me why you would need it????? surely your scope is where you need the info for and dot is mearly to speed up process,aid in poor light???
_________________ You shot it You pluck it !
Them who eats the most duck eats the most feathers! |
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PaulS Super Member
Joined: Feb 18, 2006 Posts: 4330 Location: South-Eastern Washington - the State
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Posted: Sat Jul 30, 2016 6:13 pm Post subject: Re: Negative sight heights? |
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And you are very good at it!
a sight line lower than the barrel.... I think that will pose some unique situations.
_________________ Paul
__________________
Speer, Lyman, Hodgdon, Sierra, and Hornady = reliable loading data
So and So's pages on the internet = NOT reliable loading data
Always check data against manuals
NEVER exceed maximum listed loads |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5002 Location: NC foothills
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Posted: Sun Jul 31, 2016 2:26 pm Post subject: Re: Negative sight heights? |
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The laser sits almost 3" below the centerline of the bore. The current sight is about 2.5" above the bore.
Elvis, I have a red dot sight. I looked and it's pretty hard to tell which dot is the sight and which is the laser! I'm looking for another sight that doesn't require a battery, but can be illuminated. So far I haven't made up my mind.
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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Elvis Super Member
Joined: Jul 27, 2008 Posts: 9253 Location: south island New Zealand
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Posted: Sun Jul 31, 2016 10:21 pm Post subject: Re: Negative sight heights? |
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maybe look for one with green illuminated reticle/dot...then there be no confusion
it works just as well from one side of scope too,eg if on left of cross hair under 100,right of it more than a hundy.as for your red dot...that's just got to be an issue in the making,sooner or later you will use wrong dot and go high or low.
the bit about them that really impressed me was out on edge of spotlight the beam helped illuminate a bunny rather well,making it easier to see in scope.
_________________ You shot it You pluck it !
Them who eats the most duck eats the most feathers! |
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PaulS Super Member
Joined: Feb 18, 2006 Posts: 4330 Location: South-Eastern Washington - the State
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Posted: Mon Aug 01, 2016 3:44 pm Post subject: Re: Negative sight heights? |
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A straight line from under the bore is going to cross the line of fire exactly once. The trajectory of the bullet will be above that line except at the sight-in-range, and at all ranges longer, the trajectory will be increasingly below the line-of-sight. The deviation from the laser line will be exaggerated due to the line going up and the bullet falling faster at each yard.
Although the ballistics will remain constant the "line-of-sight" is at an angle away from the ground from below the bore line instead of more parallel from above the bore. The math may be similar but the results are going to be very weird.
_________________ Paul
__________________
Speer, Lyman, Hodgdon, Sierra, and Hornady = reliable loading data
So and So's pages on the internet = NOT reliable loading data
Always check data against manuals
NEVER exceed maximum listed loads |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5002 Location: NC foothills
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Posted: Mon Aug 01, 2016 11:35 pm Post subject: Re: Negative sight heights? |
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Paul, yep, that's why I was hoping to see the trajectory "on paper".
I ordered this to stick on the carbine. It has an etched reticle so it will work without a battery. And it has the option of red or green illumination.
www.midwayusa.com/prod...icle-matte
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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PaulS Super Member
Joined: Feb 18, 2006 Posts: 4330 Location: South-Eastern Washington - the State
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Posted: Tue Aug 02, 2016 6:47 pm Post subject: Re: Negative sight heights? |
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_________________ Paul
__________________
Speer, Lyman, Hodgdon, Sierra, and Hornady = reliable loading data
So and So's pages on the internet = NOT reliable loading data
Always check data against manuals
NEVER exceed maximum listed loads |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5002 Location: NC foothills
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Posted: Tue Aug 02, 2016 8:46 pm Post subject: Re: Negative sight heights? |
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I'll just hold the gun upside down like Jerry Miculek!
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5002 Location: NC foothills
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Posted: Fri Sep 02, 2016 12:36 am Post subject: Re: Negative sight heights? |
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Sooo... No negative sight heights?
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Fri Sep 02, 2016 5:36 am Post subject: Re: Negative sight heights? |
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Pkslinger, here is an on-line cal that does negative sight height. I tried a couple before I found it as most only did positive.
www.jbmballistics.com/...aj-5.1.cgi
Wouldn't a green laser be better for your situation as it would be brighter and be more usable during daylight?
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5002 Location: NC foothills
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Posted: Fri Sep 02, 2016 6:26 am Post subject: Re: Negative sight heights? |
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Thanks Slim!
Yes, green would be better in daylight but red was a LOT cheaper...
At this point I think I'll zero the prismatic sight at 100 yards and the laser at 25 yards. We'll see if this works in actual practice. I've got a few days off here and may actually get to go to the range!
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5002 Location: NC foothills
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Posted: Fri Sep 02, 2016 6:35 am Post subject: Re: Negative sight heights? |
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I stand corrected!!! I just went back and played with PointBlank again. I entered a negative sight height and it worked fine! Maybe I fat fingered something before...
The trajectory looks odd but revealing! I'm now thinking maybe a 50 yard zero for the laser.
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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