So I just came from the range with my brother and father, where My brother again shoot 3" groups at 100 yrd but 200 yrds he shot under 2" at 200. Is it possible for a rifle to not group at 100 but straighten out by 200? He shoots consiten groups with my fathers rifle. I can't get it to group at 100 either is it possible?
Strange Grouping....
- Thread starter Comil_1983
- Start date
just having some fun
CGN Ultra frequent flyer
for me target size/ shape even the time of day (my range gets shadows from some trees on targets at the end of the day) effect how good i shoot
some days good, some days bad
you brother might have been trying harder(slower) at 200 and shooting at a smaller target
some days good, some days bad
you brother might have been trying harder(slower) at 200 and shooting at a smaller target
"...can't get it to group at 100..." Something is odd if the rifle won't group at 100, but will at 200. What size groups are you getting at 100? What cartridge, bullet, rifle and ammo?
"...is it possible?..." Yep. As daft as it sounds. Has to do with the bullet stabilizing. Any bullet wobbles(pitch and yaw) until the spinning stabilizes it. A .308" bullet, for example, out of either a .308 or .30-06 doesn't stabilize until about 300 yards.
Arrows do the same thing until the fletching starts to work. My point is that you can see an arrow stabilize. It's like somebody threw a switch. The back of the arrow wobbles(they actually bend), then it just stops and the arrow flies straight(very slick to see). Bullets do it too.
"...is it possible?..." Yep. As daft as it sounds. Has to do with the bullet stabilizing. Any bullet wobbles(pitch and yaw) until the spinning stabilizes it. A .308" bullet, for example, out of either a .308 or .30-06 doesn't stabilize until about 300 yards.
Arrows do the same thing until the fletching starts to work. My point is that you can see an arrow stabilize. It's like somebody threw a switch. The back of the arrow wobbles(they actually bend), then it just stops and the arrow flies straight(very slick to see). Bullets do it too.
One thing that I have personally found through the years of coaching and shooting. Is that the operator gets more into his/her "bubble" at longer ranges by paying more attention to all the small details of marksmanship.
Sometimes it is just a matter of target image size, too large at a given range gives a vague aim point causing a spread group. Create a specific aim point, a bulls eye target is the worst if you are using a scope unless you aim at the bottom edge where white changes to black. Black crosshairs on black target does not contribute to a good sight picture. A good target sight picture I find improves group size at least 50% all the best art.
I really don't think it is him as the shooter because he group very well with my dads gun (an old ruger in .270 win) both guns are same calibre, Both have identical optics Burris fullfield II 3x9x40. And as far as ammo it seems like his gun groups nothing at 100 His handloads don't he's tried a few powders and bullet types and yesterday we tried remington 130 grs and hornady 130s factory ammo. The hornadys are the ones that he shot very well at 200 but both of us shot 3" at 100 with this load. For targets we used a 1"red bull on 1"square grids So I actually think that it must have to do with his barrel/ stabilization of the bullet.
Not sure if this has ever been linked to before, but a good read about bullet flight.
http://www.nennstiel-ruprecht.de/bullfly/
and more to the point
http://www.appliedballisticsllc.com/index_files/EpicyclicSwerve.htm
http://www.nennstiel-ruprecht.de/bullfly/
and more to the point
http://www.appliedballisticsllc.com/index_files/EpicyclicSwerve.htm
If a bullet is not on line to a target at 100M, it will not "steer" itself back on course. PERIOD. Bullets just can't do that! There may be some miniscule affect caused IF the bullet has yaw...but not enough that you could possibly notice it between 100 and 200M.
2MOA @100M cannot become 1MOA @ 200M. Several possibilities have been suggested ...bedding...barrel heat...parallax....and even the possbility of operator error.
Just in case I don't understand the physics, and there is in fact a bullet that "steers back towards the target....let me know...I want to become the dealer!
2MOA @100M cannot become 1MOA @ 200M. Several possibilities have been suggested ...bedding...barrel heat...parallax....and even the possbility of operator error.
Just in case I don't understand the physics, and there is in fact a bullet that "steers back towards the target....let me know...I want to become the dealer!
The little video at the end of the page from that second link is a great visual reference! So It is possible and We are not crazy. I think my brother will be working up his new loads at 200 yrds now.
The principal can be demonstrated very easily.
Take a childs top, the type they spin. They are given various ways to get them turning fast, but very often, after they are up to speed and set on a surface to perform, the top of the spinner wanders around in a circle, until centrifigul force is equal on all sides, then the top sits there and spins without a wiggle.
A bullet can act the same way after it leaves the barrel.
As I mentioned before, the old time competetive shooters referred to it, poor grouping at closer range, as the bullet hadn't gone to sleep yet.
I'm actually thinking that since most modern BG scopes are set for a parallax of 200 yards, I'm kinda thinking that might just be it. Good call, Chuck. x2 I heard ya the first time, too. But if the choir ain't converted yet...
I'm not for the bullet sleep crap but target size does also seem to make sense as well.
I'm not for the bullet sleep crap but target size does also seem to make sense as well.
H4831 - As I recall, the spinning tops that I set down did not sit in one place, but wandered around before they "settled down". It seems that what you are suggesting is that they wander back to the original (center) spot when the rotation stabilizes? Lets put that top down again...and say the center of the "wobble" is held to a 3" diameter. When it stabilizes, the center of gravity (wobble) could be any place inside that 3" diameter....it would not always wander back to rest inside a smaller diameter...chance would dictate that sometimes it would...but as often as not...it goes the other way?
As I mentioned in my post, I accept the theory that yaw can bring a projectile to strike close to the center of rotation....but only a miniscule amount over 100M. It certainly cannot explain a bullet steering back 1" between 100 and 200M.
Lets simplify and take an example in two dimensions. A car is yawing as it going down the centerline of an icy highway. If slid out to the left side by 2" and stopped yawing...would it keep going in the direction of its momentum, or would it "steer" back on center line?
And, with all respect to the competetive shooters, I don't recall their claims were that they shot better groups as distances became greater...perhaps they claimed that once an unstable bullet stabilized...it did not stray as far off the center line as progression would expect. Actually, I was skeptical that they would choose an unstable bullet to start with....
As I mentioned in my post, I accept the theory that yaw can bring a projectile to strike close to the center of rotation....but only a miniscule amount over 100M. It certainly cannot explain a bullet steering back 1" between 100 and 200M.
Lets simplify and take an example in two dimensions. A car is yawing as it going down the centerline of an icy highway. If slid out to the left side by 2" and stopped yawing...would it keep going in the direction of its momentum, or would it "steer" back on center line?
And, with all respect to the competetive shooters, I don't recall their claims were that they shot better groups as distances became greater...perhaps they claimed that once an unstable bullet stabilized...it did not stray as far off the center line as progression would expect. Actually, I was skeptical that they would choose an unstable bullet to start with....
JEC, I wasn't thinking of the whole top moving around. This only happens by chance. But if you set the spinning top in something that holds the bottom from moving around, only the top will wobble around, until, as I said, centrifigul force equalizes, then the top spins without wobbling.
In spite of what some are calling it, it is not crap. It is a genuine phenomena of a bullet that will just barely stabalize. It changed the grouping enough that iron sighted target shooters picked it up.
Also, it can not be compared to a yawing car, because a yawing car is completely different than a spinning bullet at about 180,000 revolutions per minute.
However, in the case originally discussed, it could be parallax from the scope doing it.
In spite of what some are calling it, it is not crap. It is a genuine phenomena of a bullet that will just barely stabalize. It changed the grouping enough that iron sighted target shooters picked it up.
Also, it can not be compared to a yawing car, because a yawing car is completely different than a spinning bullet at about 180,000 revolutions per minute.
However, in the case originally discussed, it could be parallax from the scope doing it.
I am on board with the prospect of an unstable bullet gaining stability and thus straying less from the center of the flight path. I have seen the calculations (although I confess I can't follow the math), and understand the potential for correction is very small...and only becomes a factor over long ranges...not within the 200M the OP was wondering about..and certainly not to the tune of an inch in that distance.
The best test, is to shoot a number of five shot groups at each distance. As we all know, three shot groups can be somewhat misleading when it comes to assessing how a gun shoots or how a particular bullet perfoms.
The best test, is to shoot a number of five shot groups at each distance. As we all know, three shot groups can be somewhat misleading when it comes to assessing how a gun shoots or how a particular bullet perfoms.
