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Post by doug136 on Jul 31, 2017 7:13:32 GMT -5
I shot last nite at 400 yards . I shot 2 sighters before attempting to shoot a group . Conditions were near perfect . I noticed that i shot significantly to the right. Some of this may be because i have a tendency to cant my gun a little . I have a level on my gun but i have found i shoot much better if i dont pay attention to the level . Im thinking possibly some of my shooting to the right is spin drift ? At 400 yards im gonna need about .5 to 3/4 moa to be centered . Is this possible or is it because of me possibly canting the gun or some sort of wind currents that I can not see?
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Post by doug136 on Jul 31, 2017 7:22:45 GMT -5
My gun has a tendancy to torque or twist to the right. My thinking is that my bullet is spinning in that direction and possibly they can slowly crawl to the right ? I hear guys talk about spin drift but never really thought about it . I have never really shot much at long range . 99 percent of my shooting is at 100 yards but when i do go long range i almost always shoot to the right if conditions are calm .
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Post by nick50471 on Jul 31, 2017 7:25:28 GMT -5
There are calculators online to estimate these values. Nothing can replace actual shooting data.
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Post by nick50471 on Jul 31, 2017 7:30:26 GMT -5
My rifle shoots the same. In zero wind conditions zero dead on. At 400 I'm almost 2" right. At 500 I'm almost 4" right. I adjusted my zero two clicks left to compensate. I used a calculator to help configure my dope chart.
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Post by Kyle on Jul 31, 2017 9:02:07 GMT -5
Spin drift is a reality. Canting a rifle can cause low left and low right impacts. Since I have been using a level, my groups have improved at all ranges.
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Spin drift
Jul 31, 2017 10:17:01 GMT -5
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Post by Chad on Jul 31, 2017 10:17:01 GMT -5
I would recommend trying to keep your rifle level. It does affect your POI if it's not level. At 200 to 300 yards you may not notice it on an animal but on paper you will. The farther you extend your target the more it's magnified. There's a could clip on YouTube on canting your rifle.
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Spin drift
Jul 31, 2017 10:29:39 GMT -5
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Post by markb317 on Jul 31, 2017 10:29:39 GMT -5
I would say it is not spin drift that is moving your impact that far. With my ml with no wind at all the spin drift at 400 yds would be .15 moa which would be about between 1/2 to 3/4". I would guess that it is a breeze you don't feel and some cant of the rifle. Just my experience from the shooting I do..
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Post by elkman1310 on Jul 31, 2017 12:41:31 GMT -5
Doug forget spin drift at close distances. When we shot ultra long ranges out past 1,500 yards I played around with spin drift. Yes there is a mathematical formula for it but every time I would dial in spin drift in good conditions I would miss. The big factor is wind even when you don't feel or see any indications of wind there is always something going on because we don't shoot inside a vacuum . I have shot well past a mile with zero windage on my scope and then other days needed 30 feet yeah 30 feet. So practice is key at any distance. Muzzleloaders are terrible in the wind especially past 300 yards so your probably doing better than you think at that distance.
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Spin drift
Jul 31, 2017 14:04:58 GMT -5
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Post by doug136 on Jul 31, 2017 14:04:58 GMT -5
Im actually pretty happy with my group . At this time i dont think i can shoot much better. I can dial for the wind or what ever caused me to shoot right . Im afraid some of my shooting to the right is because i have a tendency to cant my gun . Last year at the Kentucky Challenge Mark noticed what i was doing . If i can figure out how to post a picture ill post it . Tonite im gonna try a different load and different weight of bullets. Im gonna try to pay more attention to my level
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Post by doug136 on Jul 31, 2017 14:33:56 GMT -5
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Post by doug136 on Jul 31, 2017 14:57:36 GMT -5
This is my group . I shot one sighter before shooting this 3 shot group . This was my first attempt shooting 400 yards with smokless .I have shot 500 yards with Blackhorn but never smokless at this distance . I over compensated and actually shot right and high . I shot this with a Hankins Custom using a front rest with a sand squeeze bag in the rear and Kyles 300 Accumax bullets using Carls load of 73 grains of 4198 and a wool wad at aprox 2800 fps . Tonite im gonna try some 3031 with 325 Accumaxs. If i have time im also gonna try a 84 grain load of H322 and Kyles Accumax 300s . Im trying to find the most accurate load i can shoot for the Kentucky Challenge. The gun and bullets will do it .The shooter im not so sure about !
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Spin drift
Jul 31, 2017 15:23:38 GMT -5
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Post by Deleted on Jul 31, 2017 15:23:38 GMT -5
I would have to attribute the errors to scope cant. I removed my front bag from my rest and attached a piece of lexan to the bottom of the stock that fits in the front rest. Once you adjust the feet on the rest so your scope level is proper, you can forget about the scope level during aiming/shooting. Just check it when the gun is sat in the rest.
If your reticle isn't plumb or the level is not synced with the reticle or the reticle is out of alignment with the internal turrets, it will be apparent at distance.
Muzzleloader are especially susceptible to can't errors due to the size of the bullet arc during flight.
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Spin drift
Jul 31, 2017 15:43:42 GMT -5
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Post by 12ptdroptine on Jul 31, 2017 15:43:42 GMT -5
I aggree with Scat. Scope has to be leveled properly first. Then the scope level installed level. Then you need a way to minimize the barrel torque. Another thing Rchard told me is to be sure your targets are hung level also... Drop
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Post by Richard on Jul 31, 2017 16:53:33 GMT -5
I have also dealt with bullets impacting to the right, particularly at extended ranges. Let me throw out another curve? Lets say the mounting holes on top of your receiver are not 100% in line with the center line of the bore/barrel? So your scope is looking one way but the barrel is facing another? At closer ranges it is less noticeable (depending on how out of line it is) but as you get further out, it begins to show up more and more. The same can be said if the shoulder on the barrel or the face of the action OR your recoil lug is not machined parallel? So now maybe, you scope is properly aligned with the action but your barrel is facing right or left or even up or down? All depends on where the misalignment is. Up or down is not as critical as left or right since you will just attribute it to the load. My gun always sits level due to the nature of my rest and the stock but yet most of the time, impact will tend to right when it occurs?
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AJ
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Post by AJ on Jul 31, 2017 20:15:26 GMT -5
I'd say it has more to do with scope alignment in the rings and/or shooting form. Spin drift, while it is real will not come into effect until you are 3-4x the distance you are shooting. My 25-06 was shooting to the left at 600 yards. I re-leveled the gun then re-mounted the scope and now it is much closer. One way to test is zero at 100 yards then move your POI up a revolution or two of the dial and shoot another group using the same hold. The groups should be perfectly vertical. If not re-adjust your scope in the rings.
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Post by deadeye on Jul 31, 2017 20:22:19 GMT -5
I am not buying spin drift in mz @ 400yds however @ approx. 800yds+ quite possible with little adjustment for correction. it is a consideration in ELR.
elrc.appliedballisticsllc.com/53/
even w/ cf its very difficult to pin point out due to conditions.
Our range will have what I call "coin toss" shots/strings due to thermal's & hills & valley's//just walk the course many times & you will feel the draft's changing dramatically usually changing more rapidly as the morning runs long. (eric/hando61 were discussing this one time a few shoots back while match was going on ) I think we were more confused & just let it wring itself out.
last shoot even w/ sighter board my peabrain hamster was on the ballistic wheel,contemplating 2 click's or zero,the conditions were changing rapidly & when I went on the line even w/ a sighter @ 400yds conditions calmed causing me to over compensate. I got winded & had to make a choice//group or score. spindrift & coriolis effect were non existence even shooting pretty much due west.
that shoot very many shot better @ 300 & 400yds,conditions that you have to deal with.
keep in mind accuracy & precision shoots are very difficult at our level to place high in the standings. jmho
Remember-Wind is Non-Deterministic
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Post by Deleted on Jul 31, 2017 20:45:54 GMT -5
I'd say it has more to do with scope alignment in the rings and/or shooting form. Spin drift, while it is real will not come into effect until you are 3-4x the distance you are shooting. My 25-06 was shooting to the left at 600 yards. I re-leveled the gun then re-mounted the scope and now it is much closer. One way to test is zero at 100 yards then move your POI up a revolution or two of the dial and shoot another group using the same hold. The groups should be perfectly vertical. If not re-adjust your scope in the rings. Agreed. I didn't know the extent of Doug's knowledge but he needs to do a "Tall Target Test". A small amount of movement in the tall target test can equate to much more at 300, 400, and beyond due to the arc of the projectile. Doug, I know that you were part of the following thread but since you had never experienced these issues, you may not have delved into it as far as you need to now. hanksmessageboard.freeforums.net/thread/1501/mounting-leveling-scope
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Post by doug136 on Aug 1, 2017 6:45:46 GMT -5
I have read on scope leveling . This is a Hankins build Jeff installed the scope . I have checked the scope as far as i can tell the scope is perfect . You guys are waaay over my head . I feel that i am a decent shot but by no means a expert in any way . I have the ability to shoot but the technical stuff im far behind . I really have only been playing with this sport less than 2 years . I kind of figured most of my shooting right is due to rifle cant . I was just curious if some of shooting right could be from spin drift and if spin drift was real . I honestly shoot much better if i just shoot and not worry about anything . Im very far behind 99 percent of most . Ill just keep doing what im doing and dial according . Thanks for the responses.
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Post by deadeye on Aug 1, 2017 7:25:15 GMT -5
doug you ask very good questions & believe me we don't call ourselves experts. its just that some of us have been in the game a little longer piling up experience which helps but not guarantees where our bullet will land.
*when a situation happens like drifting to the right or missing if you can hop on a atv or walk your shooting lane stopping & taking in whats happening in the course where the bullet just traveled you will come across some very interesting surprises the wind is behaving down range.* I'm aware by the time you get there it could already have changed but do this enough & it will help anyone understand what is actually going on wind wise . very valuable for me when I was doing more long range work-actual field practice. we are not looking for a excuse cup but a answer why something went wrong.
I shoot farm fields here mostly when I can,right next to my house lays a 435yd lane that has a valley,swale & woodlines at one end. there are 2 American flags that I can view approx. 600-800yds away.pay too much attention to those & your toast. it is a good training range for me & kicks me once in awhile! lesson learned many times. if I could hold a match there you would see some disgruntled expressions on shooters faces!
take care,de
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Post by Richard on Aug 1, 2017 16:13:11 GMT -5
This is why you will find a plethora of wind flags at a bench rest match! But still there are some unexplained drifts and mainly to the right. I found it today with what I consider perfect conditions? Hopefully will get a post on later this evening.
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