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LUCKY.....GROUP......CLUB ( BI - PODS - ..ONLY )

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Unread 01-12-2003, 05:42 PM
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Re: LUCKY.....GROUP......CLUB ( BI - PODS - ..ONLY )


It seems intimidating at first, but It looks solvable, lets look at what there is to work with.

I just missed a crow last month at almost the exact same distance, on a cold bore shot in 23 degree conditions so I am really confident in my elevation number since we were about 800 ft. above sea level. think of it as a "delayed" spotter. with my 600 yard zero, that puts me about 14.75 moa up at 1,050 yds, the temp is slightly warmer, and the buck is 10 yards further so they cancel, and unless I find evidence of thermals I will read the wind and go with about 1 to 10 ratio vertical to horizontal with my wind correction.

Reading the wind here is not hard, the low temps and snow will cut down on available mirage, but look at the tree cover and ground cover, this is what will make the shot possible. The debris and small branches will be a great indicator of wind speed, and a bird flying through that valley will tell you what kind of thermal rises are present. Looking for birds on branches, they tend to stick their faces into the wind.
In hills like that, there are thermals that run in and out, up and down, this is what will bite you if you don't find them. In the afternoon the air tends to run down hill, and in the morning it runs up hill, faster if the sun is shining on the hillside. Weight what you see on the nearest hill to your location, watch the fur of small animals, and the feathers of small birds. Leaves that occassionally fall from the tops of trees.

I would be concerned if there is much overhang on the rock, this presents a problem if the buck is too far under the rock. If he is just below, its no problem.

Lets say there is a 15 mph wind from 3:30 to 9:30 my full value 10 mph wind correction would be about 7 moa times 1.5 for the higher wind speed gives me 10.5 moa times .95 because of wind direction minus .5 for yaw gives me about 9.5 Moa for wind correction and about 4 clicks down to take care of the right to left vertical component.

Dead buck. [img]images/icons/smile.gif[/img]

[ 01-12-2003: Message edited by: S1 ]
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Unread 01-12-2003, 06:23 PM
Silver Member
Join Date: Nov 2001
Location: tennessee
Posts: 480
Re: LUCKY.....GROUP......CLUB ( BI - PODS - ..ONLY )

Went to the range today to try some new loads. Rifle was M70 300winmag, Leupold 6-18/40 target, off a harris bipod, shot nearly free recoil. Loads were all Rem cases and CCI 250 magnum primers. Bullets were 178gr Hornady A-max(thanks S1), RL22 powder, oal. 3.555
When I left there was very little wind. At the range wind was 5-8mph from 4:30-6:00 o'clock. All groups were shot at 100yds. Three targets left to right and another three below.
75gr shot at first target.
75.5gr shot at second target.
76gr shot at third.
Then 75gr at first target on bottem, 75.5 at next, etc., etc.. Untill I had shot six three shot groups. This, I believe gives a more representitve group size, as all rounds have the same amount of fouling. Anyways the average group size was .71moa. With the sweet spot at 76gr, average was .48moa, largest, .555moa. Smallest measured .421moa. [img]images/icons/smile.gif[/img] In the last few days I have been trying different methods of holding the rifle while using a bipod. For this particular rifle, dug in were the rifle is extremly low, slight pressure on butpad, with sandbag all the way to the rear, as far as it will go, light contact with my ring and pinky finger, and cheek just resting naturaly on comb. So far this producedes CONSISTANT sub-moa performance out to 440yds, even on firm surfaces. [img]images/icons/smile.gif[/img]
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Unread 01-12-2003, 06:33 PM
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Re: LUCKY.....GROUP......CLUB ( BI - PODS - ..ONLY )


Looks like the I.H. needs some L.O.T. before the P.O.N. get really F.P. [img]images/icons/grin.gif[/img]
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Unread 01-12-2003, 10:29 PM
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Re: LUCKY.....GROUP......CLUB ( BI - PODS - ..ONLY )

[ 01-12-2003: Message edited by: S1 ]
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Unread 01-12-2003, 10:43 PM
Gold Member
Join Date: Sep 2001
Location: North, Texas
Posts: 612
Re: LUCKY.....GROUP......CLUB ( BI - PODS - ..ONLY )

I was taught that if you feel a light breeze on your face that the wind was about 4 mph. Leaves on a tree that move constancely are being moved by a 5-8 mph wind. But if you see branches swaying then the wind is blowing about 15 mph.

So I try to look for things around the object that I want to shoot to help figure out wind conditions.

Hopes this helps someone with reading the wind. My great grand father told me that when I learning to hunt squirrels.
Courage,Spirit and Honor
Pass It On
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Unread 01-12-2003, 10:51 PM
Bronze Member
Join Date: Dec 2002
Location: Northwest MN
Posts: 76
Re: LUCKY.....GROUP......CLUB ( BI - PODS - ..ONLY )

All right, here we go <fastens his bronze breastplate, while checking to make sure sword is loose in the scabbard>

S1's attention to detail is right on; but, to make a theroetical answer, we're going to have to assume a few things, or state them at the very least. Given the conditions you set forth, this is what I come up with given my load criteria <which I'll list.>

I would've missed on my first shot--forgetting that the angular drop would not work with my *standard* 100 yard zero [in fact, Dave King just brought this very topic up today! <chuckles>] My sight height I actually figured for 2", which, as best I can measure, appears to be accurate. Actual load is a .338 300gr. SMK at 3195fps. I estimated a downward angle of 17 degrees, and an anglewind direction offset of 35 degrees. I'm probably muffing it up horribly all ready, but if he starts to run, maybe he'll fall for the accoustics trap of echo and be spooked towards me after the shot. [img]images/icons/smile.gif[/img]

OK, if I did everything correctly, given the new conditions I come up with about 3.9 MOA for windage, and....about 19.8 MOA for drop. I changed the BC values, also. For the best I can tell, the 300 gr MK has about a...797 BC. I gave it three values, in decending order: .797, .780, .767. I don't know exactly how accurate these figures are; as I said, I've only been able to test the weapon out to 700 yards, and so far these figures have come very close to field data. The area I may have muffed the biggest would be angular drop--17 degrees might not be right on! <chuckles> In Minnesota, I did a lot of shooting across lakes <talk about a thermal problem!!!--updrafts to drive a person to insanity. I wish I could find better places, because for a new shooter, it introduces too damned many variables to make analysis completely efficient.> The difference I came up with for a theoretical drop at 100 yards level fire with zero range set to 5 yards <stupid program would compensate any lower, but that's with .15", anyhow" and drop if there were a 17 degree angle upon sight-in was .993% of full value, so I would think my drop chart checks out; the MOA difference is slight. Does this seem reasonable to you? Thanks for posting a good challenge; We'll call it virtual training! Keeps me sane while I'm suffering from withdrawl sickness.


Assumptions: the deer is NOT wearing body armor, the birds are actually facing INTO the wind <unlike last years frigging duck decoys of mine>, and the thermal up drafts are starting to equalize <ambient light condistions seem consistant, it appears to be mid-afternoon, I would say humidity LOOKS slightly <20%?> greater than 50%, but I've never been out your way, so I would have no clue. I would say, aside from the wind, conditions should be as stable as they're likely to get. Of course, that's easy to say; I'm sitting in a chair in my reckroom. Upon being there, I might instantly insist you take the shot!! I would want to watch for as long as I could in that type of conditions. In all honesty, I try not to shoot in wind stronger than 10mph; I'm still a greenhorn!
The Zebra
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Unread 01-12-2003, 11:18 PM
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Re: LUCKY.....GROUP......CLUB ( BI - PODS - ..ONLY )

[ 01-13-2003: Message edited by: S1 ]
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