problem shooting at 200 yard! help
- Thread starter SanQ
- Start date
Wind can be VERY subtle. Those of us who shoot competitively occasionally get skunked by phantom breezes. I shot this year in the World Long Range Championship and had the pleasure of watching the 900-metre shoot off between David Luckman and Mirko Teglasi. Both of those guys got blown at least into the 8-ring by surprise gusts, and they are the best shooters in the world.
Even at 200 metres, the wind can creep up on you and be a factor -- even if the flags and mirage look completely calm.
Even at 200 metres, the wind can creep up on you and be a factor -- even if the flags and mirage look completely calm.
When you get it all figured out please let us know. I have been shooting fullbore for 15 years and still don't have all the answers
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
SanQ, your shooting is very good and this is definitely a WIND thing. Also, consider the number of shots fired and how warm your barrel is.
If it is warm and the ambient air cool, you will get mirage off your barrel. Since you are looking through that mirage, it will change your POI unless you adjust for it or eliminate it with the use of a mirage shield. With a slight breeze, it can create the same 'wind' related mirage as you would watch for before the target.
Doesn't take much wind to push you that far. Looks like you were shooting in a light gusty condition going left to right.
To get them all in one hole, you either have to adjust for the wind or shoot on days that are very calm.
Jerry
If it is warm and the ambient air cool, you will get mirage off your barrel. Since you are looking through that mirage, it will change your POI unless you adjust for it or eliminate it with the use of a mirage shield. With a slight breeze, it can create the same 'wind' related mirage as you would watch for before the target.
Doesn't take much wind to push you that far. Looks like you were shooting in a light gusty condition going left to right.
To get them all in one hole, you either have to adjust for the wind or shoot on days that are very calm.
Jerry
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nice target
what is the twist and depth of the rifling in the barrel???
Can the rifling handle a little more bullet length and weight???
have you tried other bullet types? the Berger is a long ( for caliber) bullet with a very small bearing surface to engage the rifling, and handloading will make it subject to canting in the neck of the case( check the bullet tip run out) which will magnify the uncentred condition at longer ranges.
but by the pics of your target i'd agree with others and say that wind and optics play a part in the group ( very nice btw)
a heavier shorter bullet can eliminate a little of the wind effect by having a smaller surface area exposed to the wind and more energy at similar velocities.
just my $0.02
tg
what is the twist and depth of the rifling in the barrel???
Can the rifling handle a little more bullet length and weight???
have you tried other bullet types? the Berger is a long ( for caliber) bullet with a very small bearing surface to engage the rifling, and handloading will make it subject to canting in the neck of the case( check the bullet tip run out) which will magnify the uncentred condition at longer ranges.
but by the pics of your target i'd agree with others and say that wind and optics play a part in the group ( very nice btw)
a heavier shorter bullet can eliminate a little of the wind effect by having a smaller surface area exposed to the wind and more energy at similar velocities.
just my $0.02
tg
- Location
- Ft. Mac. Alberta
I also think it could be wind, but there is another factor to look at also, one that would not be present unless a person was watching you shoot.
Tthat is your length of time in between shots.
Even with a light recoiling round like the 6BR if you do not take time to let your muscles relax they tend to bunch up, and inconsistant trigger squeeze is often the result.
The group tends to migrate down and right, this is why I mentioned it.
On a heavier cartridge this would be very evident if trigger control were the culprit, but like I said, on the 6BR it can be very hard to detect.
Nice hit on the fly BTW!
Cat
Tthat is your length of time in between shots.
Even with a light recoiling round like the 6BR if you do not take time to let your muscles relax they tend to bunch up, and inconsistant trigger squeeze is often the result.
The group tends to migrate down and right, this is why I mentioned it.
On a heavier cartridge this would be very evident if trigger control were the culprit, but like I said, on the 6BR it can be very hard to detect.
Nice hit on the fly BTW!
Cat
Looks like wind. At longer ranges, I only measure group height when comparing loads. Your group height looks like a very good group size.
For starters, put a wind flag 25 yards in front and 50 yards in front and shoot when both flags show the same wind, each time. You will want to study the flags for awhile and pick a condition that keeps coming back for awhile.
Be aware of cant. As part of your mental check list for each shot, level the sights. If the back ground does not have a level reference, get a bubble level for your scope - and use it. Right handed shooters tend to start canting to the right, this gives a low right string to the group - just like what we see here.
At longer distances the short bullets do not group as well as the long bullets, because of wind. A bench rest rifle often will group very well at 100 to 300, whereas a target rifle will do better at longer distances due to a faster twist that can handle longer bullets.
In a 22 cal rifle the 75 and 80 grain bullets will stay with the 308 all the way to 1000 yards. A 69 grain bullet would be very poor, unless it was at 5;30 am in a dead calm.
I have shot both calibers in testing at 1000 yards, shooting both groups on the same paper, since the holes are easy to tell apart. Both shoot groups around 10" high, but the 22 group is usually slightly narrower than the 308. That is, the 80 gr Sierra drifts a bit less than the 155 Sierra. Both are launched at around 2950 fps.
There are other differences between shooting 100 yards and 300 yards that suggest the same load - bullet are not called for.
Barrels are rifled to impart spin and stability to the bullet. From the time the bullet leaves the muzzle to the time the bullet stops oscillating (I call it "wiggle-waggle") takes at least 50 yards and maybe beyond 100. A bullet that is spun faster than necessary (over stabilized) will settle down faster and show a better 100 yard group, but over stabilization tends to make a bullet group worse beyond 100 yards and cause real problems at longer ranges, when the bullet is coming down.
A bullet is spinning at very high RPM, so acts like a gyro. At long range the barrel is pointed up and the bullet maintains this angle, all the way down range. At 1000 yards it is arcing down quite steeply, but the bullet itself is still pointed up at the same angle it left the muzzle at – because it is gyro stabilized. This attitude exposes the side of the bullet to the air and causes problems for the last 100 yards or so.
If the bullet is spun just fast enough to be stable, the groups for the first few hundred yards may not be impressive, but the bullet at long range will tip over and point down as it comes down to the target. Such bullets shoot better at long range. However, if you remember what happens to a gyro when it tips - it points sideways. So a bullet at long range will always enter the target with some attitude. It is either pointing upwards or to the side. The target markers have often commented on the egg shaped bullet holes.
Rifle shooters are generally unaware of the “why” but they do know that certain twists work better at long range, and they are the slower twists.
The people who have made this into a science are artillery designers. It is important to them that their shells tip over and come down point first.
In 308, a 1”14 will shoot match bullets up to and including 180 grains. The ideal twist for 155 gr bullets is 1:16. However, to actually see and measure the advantage of a 1:16 over, say, a 1:12, one would need to test a dozen identical barrels and even then I am not certain I could see the difference. The trade off is long range vs short range performance, and measuring long range results is difficult, unless one has a 1000 yard tunnel.
Personally, in 308 I buy 1:14 and 1:13 barrels. Now that I am shooting 32” tubes (higher velocity and RPM) I should stick with 1:14.
For starters, put a wind flag 25 yards in front and 50 yards in front and shoot when both flags show the same wind, each time. You will want to study the flags for awhile and pick a condition that keeps coming back for awhile.
Be aware of cant. As part of your mental check list for each shot, level the sights. If the back ground does not have a level reference, get a bubble level for your scope - and use it. Right handed shooters tend to start canting to the right, this gives a low right string to the group - just like what we see here.
At longer distances the short bullets do not group as well as the long bullets, because of wind. A bench rest rifle often will group very well at 100 to 300, whereas a target rifle will do better at longer distances due to a faster twist that can handle longer bullets.
In a 22 cal rifle the 75 and 80 grain bullets will stay with the 308 all the way to 1000 yards. A 69 grain bullet would be very poor, unless it was at 5;30 am in a dead calm.
I have shot both calibers in testing at 1000 yards, shooting both groups on the same paper, since the holes are easy to tell apart. Both shoot groups around 10" high, but the 22 group is usually slightly narrower than the 308. That is, the 80 gr Sierra drifts a bit less than the 155 Sierra. Both are launched at around 2950 fps.
There are other differences between shooting 100 yards and 300 yards that suggest the same load - bullet are not called for.
Barrels are rifled to impart spin and stability to the bullet. From the time the bullet leaves the muzzle to the time the bullet stops oscillating (I call it "wiggle-waggle") takes at least 50 yards and maybe beyond 100. A bullet that is spun faster than necessary (over stabilized) will settle down faster and show a better 100 yard group, but over stabilization tends to make a bullet group worse beyond 100 yards and cause real problems at longer ranges, when the bullet is coming down.
A bullet is spinning at very high RPM, so acts like a gyro. At long range the barrel is pointed up and the bullet maintains this angle, all the way down range. At 1000 yards it is arcing down quite steeply, but the bullet itself is still pointed up at the same angle it left the muzzle at – because it is gyro stabilized. This attitude exposes the side of the bullet to the air and causes problems for the last 100 yards or so.
If the bullet is spun just fast enough to be stable, the groups for the first few hundred yards may not be impressive, but the bullet at long range will tip over and point down as it comes down to the target. Such bullets shoot better at long range. However, if you remember what happens to a gyro when it tips - it points sideways. So a bullet at long range will always enter the target with some attitude. It is either pointing upwards or to the side. The target markers have often commented on the egg shaped bullet holes.
Rifle shooters are generally unaware of the “why” but they do know that certain twists work better at long range, and they are the slower twists.
The people who have made this into a science are artillery designers. It is important to them that their shells tip over and come down point first.
In 308, a 1”14 will shoot match bullets up to and including 180 grains. The ideal twist for 155 gr bullets is 1:16. However, to actually see and measure the advantage of a 1:16 over, say, a 1:12, one would need to test a dozen identical barrels and even then I am not certain I could see the difference. The trade off is long range vs short range performance, and measuring long range results is difficult, unless one has a 1000 yard tunnel.
Personally, in 308 I buy 1:14 and 1:13 barrels. Now that I am shooting 32” tubes (higher velocity and RPM) I should stick with 1:14.
