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  #31  
Old 03-29-2011, 07:08 PM
hoytcanon
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Quote:
Originally Posted by MKnarr View Post
Ok, you are correct. I give up.
Again... I was not talking about the effects of wind... I was talking about speed and distance... PERIOD. A slower projectile will arrive at a given target after a faster projectile... all else being equal... period. (later than = longer elapsed time). Have a good day, happy shooting.
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  #32  
Old 03-31-2011, 02:28 PM
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Well, I see some of you hounded MKnarr away. Bad Ju Ju, bad karma.

Mark
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  #33  
Old 04-01-2011, 02:34 PM
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Quote:
Originally Posted by hoytcanon View Post
Again... I was not talking about the effects of wind... I was talking about speed and distance... PERIOD. A slower projectile will arrive at a given target after a faster projectile... all else being equal... period. (later than = longer elapsed time). Have a good day, happy shooting.
correct me if i am wrong, but if an object is subject to the wind longer it will be effected more? AKA the slower the velocity the more wind drift (assuming the same projectile)
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  #34  
Old 04-01-2011, 03:27 PM
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Quote:
Originally Posted by rem View Post
correct me if i am wrong, but if an object is subject to the wind longer it will be effected more? AKA the slower the velocity the more wind drift (assuming the same projectile)
rem

All else remaining equal, standard velocity .22 RF has less wind deflection than high velocity .22 RF.

The physics and math behind this are beyond me but it seems to boil down the greater percent reduction in velocity experienced by the .22 RF high velocity.

For confirmation go to the Nationals at Camp Perry during the small bore prone matches fired at 50 and 100 yards outdoors. I doubt you will find a single box of high velocity ammo on the line.

When you get into slick/aerodynamic centerfire bullets at 2,500 FPS and more, simple time of flight seems to be the major factor in wind deflection.

What applies to a blunt, slow .22 or a .45-70 out of a 18" twist barrel at 1000 FPS does not necessarily apply to 6.5mm VLD bullet launched at 3200 FPS out of a 8" twist barrel.

For both rimfire and centerfire bullets which have muzzle velocity greater than the speed of sound, when the bullet decelerates down to the speed of sound it experiences "aerodynamic buffeting" which causes poor accuracy and may even tip the bullet and cause it to keyhole.

This trans-sonic buffeting is what nearly killed Chuck Yeager when he first broke the sound barrier in the X-1.

Regards

Jim
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  #35  
Old 04-01-2011, 03:39 PM
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Excerpted verbatim from Bryan Litz's Applied Ballistics For Long Range Shooting, Chapter 5: Wind Deflection:

"Actual wind deflection is directly proportional to lag time and crosswind speed." (p. 68)

"In order to minimize wind deflection, you have to minimize lag time." (p. 69)

"Given a constant level of initial energy, the heavier bullet ends up with less lag time because the increased BC reduces lag time more than the velocity depression increases it." (p. 77)

"The preceding analysis may beg the following question from some readers. Is it possible to fire the lower BC (lighter) bullets fast enough that they have less lag time than the higher BC (heavier) bullet, and how much faster would the lighter bullets have to be fired to accomplish that? The short answer is: Yes, it's possible, but the lighter bullet would require a great deal more speed. As the previous sections showed, it takes a lot of extra muzzle velocity to accomplish the same lag time reduction as a small increase in BC." (p. 77)

"In a trade-off between low BC (light weight) bullets at high speed compared to high BC (heavy) bullets at reduced speed, the high BC bullets at a lower speed will produce less wind deflection." (p. 86)

EDIT:
From a PDF available on Litz's web site:

"The question is, how much velocity can you give up with a higher BC bullet, and still have less lag time?..
...As a general rule, you can go about 496 fps slower for every +0.100 counts of BC, and match wind deflection."

Last edited by Tennessee Slim; 04-02-2011 at 09:37 AM.
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  #36  
Old 04-01-2011, 03:44 PM
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One factor that may be a portion of this discussion about the wind sensitivity of the projectile, is that, to my understanding, the ballistic coefficient of the bullet changes with velocity. The standard 22lr bullet shape has less drag and correspondingly less wind drift sensitivity if it's going slower. If the ballistic coefficient goes up faster than the time of flight increases, maybe that's another reason why the slower bullets perform better?

DPSTX
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  #37  
Old 04-03-2011, 01:51 PM
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Quote:
Originally Posted by Tennessee Slim View Post
Excerpted verbatim from Bryan Litz's Applied Ballistics For Long Range Shooting, Chapter 5: Wind Deflection:

"Actual wind deflection is directly proportional to lag time and crosswind speed." (p. 68)

"In order to minimize wind deflection, you have to minimize lag time." (p. 69)

"Given a constant level of initial energy, the heavier bullet ends up with less lag time because the increased BC reduces lag time more than the velocity depression increases it." (p. 77)

"The preceding analysis may beg the following question from some readers. Is it possible to fire the lower BC (lighter) bullets fast enough that they have less lag time than the higher BC (heavier) bullet, and how much faster would the lighter bullets have to be fired to accomplish that? The short answer is: Yes, it's possible, but the lighter bullet would require a great deal more speed. As the previous sections showed, it takes a lot of extra muzzle velocity to accomplish the same lag time reduction as a small increase in BC." (p. 77)

"In a trade-off between low BC (light weight) bullets at high speed compared to high BC (heavy) bullets at reduced speed, the high BC bullets at a lower speed will produce less wind deflection." (p. 86)

EDIT:
From a PDF available on Litz's web site:

"The question is, how much velocity can you give up with a higher BC bullet, and still have less lag time?..
...As a general rule, you can go about 496 fps slower for every +0.100 counts of BC, and match wind deflection."
that makes perfect sense, if the low velocity bullets have the same .136 BC as the high velocity bullets then the physics don't work.
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  #38  
Old 04-03-2011, 02:52 PM
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Awesome thread.
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  #39  
Old 04-04-2011, 08:33 AM
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Yes it is. And it all started with a soda can set at 250 yards. The .22 rimfire is no different from anyother seperate round of ammunition. There will always be someone stretching it out further then many believe is possible - not for the sake of hunting, but rather for the personal adventure of the shot when shooting at a target once the shooter has found the subsonic round that works best for this purpose. Pure clean fun and enjoyment that doesn't hurt anyone, but seems to step on many self proclaimed experts toes that say, "it can't be done." Well, bottom line - it can be done regardless of the nay sayers.

Last edited by Joe M; 04-04-2011 at 08:36 AM.
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  #40  
Old 04-04-2011, 11:02 AM
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It's a shame you guys ran off MKnarr.

Did a little shooting on paper this weekend. All I've done up to this point is shoot at inanimate objects and "reactive" targets. Was using a 10/22 build utilizing a Nodak receiver, Clark mid-weight barrel, KID two stage trigger and Boyd's Tacticool stock equipped with a Bushnell Elite 3200 10x tactical. Ammo was Wolf MT. This combination shoots under 3/8"@50yds and "@100yds. I have just enough elevation adjustment to zero with the first mil-dot.

Wind was a problem but the weather was so nice I decided to shoot anyway. Range is a lasered 235yds. Waiting between breezes I was able to get maybe a third of the shots clustered into around 3" but any amount of wind would drift them several inches. Had the same results with my Savage MKII with Rifle Basix trigger that shoots similarly at shorter ranges. I will try again on a windless day but I'm convinced it won't do any better than 4" at that range, under ideal conditions.
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  #41  
Old 04-04-2011, 11:20 AM
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I have a Mossberg light target gun that I've had since I was a teenager. It shoots really well -cloverleafs at normal rimfire ranges. It also happens to like hypers, and I've shot some just over 1" groups with it nearing 100yrds. But I've yet to really take it serious at long range grouping bc its factory trigger, although dead crisp, weighed in at 7lbs! And the scope I had on it for all those years had insufficient eye relief.

So...I fixed it -honed the hammer/sear engagement step down to a still crisp 3lbs. And I just put a 3x-12x scope on it with PA. Now if the wind would only quit, I'll see what I really have. If I get something decent at 100, I'll try for 200.
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  #42  
Old 04-04-2011, 07:20 PM
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I would highly recommend that if anyone interested in shooting .22 Rimfire out to, and beyond, 200 yards, they should go to Sniper's Hide (Rimfire section) and read up on it. It takes more to get it done then what one may think, but you're going to have to make the investment in time and equipment (such as a quality scope that is mounted on at least a 20MOA base, or shimmed to 20MOA. A rifle with a decent trigger adjustment such as a Savage heavy barrel FV or BV with accu-trigger. A good bipod like a Harris. Find the best subsonic ammo that works with your rifle for these long ranges, and then go to shooting and learn as much as you can about the wind and conditions you are shooting in. You will also need a desire to do it, and once you do it - it will open up a whole new sport for you that you never thought possible.

There is a wealth of knowledge over at SH on this very subject that is very valuable to the longrange .22 Rimfire shooter. Regardless of how good and enjoyble RFC is to all of us here, you will not find the wealth of info on 200+ yard shooting here, as you will find there.

This pretty much ends my following this thread as I simply can not add anything else that you (if you are interest) can't find yourself with a little time and effort in researching the topic.
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  #43  
Old 04-04-2011, 07:40 PM
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22 LR Wind Drift at Long Range

Firing a rimfire rifle long distance is similar to long distance pistol shooting. The wind effect is so important that your ability to read the wind is more important than the ammunition you use.

It is stunning how much a 5 mph wind will move a 22 LR bullet on a 100 yard shot, or a 200 yard shot.

Here is a wind deflection chart with some comparable figures out to 100 yards. As an example, a 10 mph crosswind will move a 40 gr subsonic (1080 fps) bullet about an inch at 50 yards and about 4.15 inches at 100 yards. Doubling the range seems to cause about a four fold increase in deflection. Extrapolate this curve out to 200 yards and you get a rather dramatic change in impact point of about 16 inches.

http://www.gunsmoke.com/guns/1022/22drift_cross.html
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  #44  
Old 04-06-2011, 12:16 AM
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That was a good read.

Thanks.

I will refer to this...............
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  #45  
Old 04-06-2011, 10:03 AM
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Quote:
Originally Posted by Joe M View Post
Pure clean fun and enjoyment that doesn't hurt anyone, but seems to step on many self proclaimed experts toes that say, "it can't be done." Well, bottom line - it can be done regardless of the nay sayers.
I have not seen any comments that it cannot be done.

The question is how consistently can it be done.

This is the difference between a marksman who shoots strings of shots for score with a time limit and a plinker who shoots until he scores a hit and calls the exercise a success.

Nothing wrong with informal plinking. That is what I did for most of my life. Used to go out in a plowed field and pick out a dirt clod way over yonder and blaze away with Kentucky windage and elevation until I hit it, pat myself on the back and go home. It was a lot of fun but did not make me a better rifleman.

Last fall I dusted off the M1A and shot a highpower match for the first time in years. My first sighter shot from offhand at 200 yards was a pinwheel X (X-ring is 2" diameter). In the following 20 shots for record offhand I had zero X's, a couple of tens and the rest were all over the target which has a 37" diameter 5-ring. That X was a fluke. I just happened to slam the trigger at the precise time the rifle was pointed at a spot where my lousy trigger control would move the rifle so it was pointed at the X ring when the bullet left the muzzle. But it was meaningless.

It's all about consistency - if you fire 10 or 20 shots back to back at cans 250 yards away, how many times will you hit them?

If you hit it 50% of the time today when the wind is light and steady, will you score 50% tomorrow when the wind is heavy and variable?

If a person wants to know what (s)he can do, hang a paper target out there at 200yards or more and shoot 20 shots for score. If you are not keeping score you cannot improve.

I think this controversy boils down to a failure to communicate between informal plinkers and competetive marksman. These groups have different definitions of (a) success, and (b) fun.

Regards

Jim
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