Greetings,
I want a second take on that. I use sierra matchking 168gr (#2200) in .308 and past 600 yards, the accuracy begins to suffer pretty badly. especially when there is wind. It was suggested to me to switch to 155gr Palma MatchKing (#2156). It has a superior BC and the drop will be less considering that bullet can be pushed way faster.
Anyone use #2156 pas 600 yards (Anything under 600 yards is irrelevant for me in this discussion because I can cloverleaf the #2200 at 200 yards but past 600 the accuracy drops to 2.5 MOA)? How do they perform for you, especially with wind?
Thank you
What rifle are you shooting do you want to shoot this in?
Si vous avez besoin de plus, faites-le moi savoir.
VOICI:
http://www.exteriorballistics.com/ebexplained/4th-rifle_tables/index.cfm
http://www.exteriorballistics.com/ebexplained/4th-rifle_tables/pdf/308155hpbt.pdf
http://www.exteriorballistics.com/ebexplained/4th-rifle_tables/pdf/308175hpbt.pdf
http://riflemansjournal.blogspot.com/2011/01/cartridges-1000-yard-308-load.html
http://riflemansjournal.blogspot.com/2010/10/cartridges-308-palma-preparation-and.html
http://riflemansjournal.blogspot.com/2010/10/cartridges-loading-308-for-palma.html
http://riflemansjournal.blogspot.com/2011/01/cartridges-1000-yard-308-case-capacity.html
https://www.snipercentral.com/308.htm
Quote from: kestak on June 20, 2014, 07:50:14 AM
I want a second take on that. I use sierra matchking 168gr (#2200) in .308 and past 600 yards, the accuracy begins to suffer pretty badly. especially when there is wind.
Might I suggest that the bullet accuracy may be just fine but your accuracy may be suffering? :cool2:
It takes more than just a few clicks of elevation to hit "accurately" at 500+ yards. 10MPH wind in a single direction can give you over 36" of bullet drift in that single direction. The "problem"" is that wind is often not blowing in that one single direction for the whole 600 yards. It can vary in velocity and direction drastically. This is the reality that many people are not aware of. You also have to take mirage into consideration as that can also be a significant factor.
Wind, position issues, respiratory pause issues, trigger control, head position, all become bigger concerns at 600+ yards. However, I can say that as far as bullets go for 600 the 168 Matchking is among the best. Unless I was shooting a rifle with a palma twist, I would try 173's or 175's before I went to 155 (if I was sure that the problem was the bullet). MANY national championships were won with Sierra 168's.
I would suggest a drill of shooting the highpower SR target at 200 yards until you can consistently shoot it clean, or better yet, shoot all X's. Once you can do that (and maybe before), I bet your issues at 600 will go away.
Thank you all for the answers.
I think DEH hit the nail by pointing me on those links. Especially the articles on reloading for the 308 for 1000 yard targeting.
I do not neck turn.
I do not check case capacity.
I do not check the concentric.
I weight the powder .1 and not .01 (or maybe .05, I do nto recall at this early time).
At 600+, all those factors put together begin to show on accuracy.
I've been shooting a lot at 600 yards lately with my Service Rifle, and while I'm hardly an expert, I think you're answer does not lie with your ammo. JMDavis is, I think, on the right track, and it seems to me your ammo is the least of the challenges at 600 yards.
I shot this past weekend at Fort Benning with the AMU, and saw plenty of those guys shoot 198's and 199's (out of 200) at 600 yards with their service rifles in .223. The ammo they shoot is 80 grain .223 factory ammo from Black Hills. Now while Black Hills certainly makes good ammo, this isn't benchrest ammo that's been neck turned, sorted for case capacity, concentricity checked, or anything else. But those AMU shooters are really good at reading the wind, and they make very few (if any) errors in their positions and their shooting.
Switching to 155 grain Palma bullets (or 175 SMK's) isn't likely to make much difference, at least in my opinion. Making better ammo is always a laudable goal, and neck turning, case sorting, concentricity checking, powder trickling, etc. will all help there, but it's not going to turn a 2 1/2 MOA group (which isn't bad at all at 600 yards) into a 1 MOA group.
Agrivere
Check the sd of your loads. It's not the bullet. If you are getting sub Moa at 200 yds at what point does the group start to open up? Is there a noticeable vertical component in the group? Are you testing in the same conditions? Most of the other causes have been covered.
Milt
The winner of the President's 100 in 2011 at Camp Perry is a man named Konrad Powers from IL. He loads all of his ammo on a Dillion progressive, weighing nothing, turning nothing and and shoots a .223 with 80gr Sierras at 600 yards. He regularly shoots slow prone scores of 195+ with iron sights at a target with a 2 moa 10 ring. His secret isn't his ammo, it isn't his vision, and it isn't his rifle. His secret is a good position, a good npoa and relaxing.
Here are his thoughts on slow prone at 600 yards with a sling.
http://www.sw-hearing.com/konrad/thoughts/slow_prone.html
That's some good stuff!
Quote from: jmdavis on June 26, 2014, 12:51:16 AM
The winner of the President's 100 in 2011 at Camp Perry is a man named Konrad Powers from IL. He loads all of his ammo on a Dillion progressive, weighing nothing, turning nothing and and shoots a .223 with 80gr Sierras at 600 yards. He regularly shoots slow prone scores of 195+ with iron sights at a target with a 2 moa 10 ring. His secret isn't his ammo, it isn't his vision, and it isn't his rifle. His secret is a good position, a good npoa and relaxing.
Here are his thoughts on slow prone at 600 yards with a sling.
http://www.sw-hearing.com/konrad/thoughts/slow_prone.html
Thank you for posting this. Very good information. Regards, Two Wolves :cool2:
A much bigger factor than most realize is rifle cant. At just 500 yards, each degree of rotation off vertical equals about 1 inch of horizontal error. Vertical error, meanwhile, remains mostly negligible.
If you are rotated 18 degrees, then your horizontal error is about 19 inches. Torso size! Think this is a lot? Consider an analog clock that is three minutes before noon. The minute hand is (3/30) x 180 degrees= 18 degrees off vertical. Can you hold to within just 3 minutes of high noon? If so, you have 19 inches of horizontal error! To reduce this, a bubble level can help limit you to within 3-5 degrees, or to within about 3 to 5 inches of horizontal error. Steady hold factors practiced at less than 200 yards for a center fire rifle won't help you practice getting rifle cant right. Shooting a .22 LR rifle at more than 100 yards will help, though.
I had to re-learn steady hold factors when I first shot at 600 yards; my horizontal errors were way off. I had corrected for Windage properly. The problem was my rifle cant!
At 600 yards, the error is even larger than 1 inch per degree of error.
Be sure to mount targets horizontal, too. If your target is 6 or 7 degrees off horizontal at 500 yards, then your sight picture will throw off your horizontal accuracies, too, by about 6-7 inches. It's worse than this at 600 yards!
(I have been working on a set of KD notes; I was surprised when I first analyzed the effect of unintended sight rotation!)
-gb
Cant is only an issue if you don't know your zeroes and your rifle. Winner of 37 National Championships in highpower, longrange, smallbore, and highpower silhouette David Tubb shoots with a cant. He minimizes it with rotated sights, but he still shoots with one.
If you can shoot without a cant, do so. But in and of itself a cant is not a major issue, if you know your zeroes and keep the cant consistent.
Article on Cant:
http://www.accurateshooter.com/optics/canting-effect-on-point-of-impact/
Quote from: jmdavis on July 11, 2014, 12:56:46 AM
Cant is only an issue if you don't know your zeroes and your rifle. Winner of 37 National Championships in highpower, longrange, smallbore, and highpower silhouette David Tubb shoots with a cant. He minimizes it with rotated sights, but he still shoots with one.
If you can shoot without a cant, do so. But in and of itself a cant is not a major issue, if you know your zeroes and keep the cant consistent.
Article on Cant:
http://www.accurateshooter.com/optics/canting-effect-on-point-of-impact/
Yes, David Tubbs shoots with his rifle canted. (His books are excellent, too, where he explains this!). But, his sights are not canted! He found that he could control his rifle cant, for improving his steady hold factors, while not having his sights canted. His sights are rotated from his rifle. For us mere mortals, the key is keeping your sights level. You can know your come ups precisely, and have excellent hold factors, and correct for wind perfectly. But if you cannot hold your sights level to within a couple degrees, your horizontal errors will throw you off the target center. Excellent article on cant, incidentally! Thanks for the link!
-gb
Tubb attempts to minimize his cant via sights that can be adjusted. But he still has cant relative to the sights. His books are good. So are the DVD's on the T2000.
It doesn't matter if the sights are level as long as they are consistent. Most shooters who have cant have it in standing or sitting as the attempt to keep their heads erect and bring the rifle to the eye rather than vice versa.
QuoteIt doesn't matter if the sights are level as long as they are consistent.
I think you hit the nail on the head here, especially when shooting at 600 yards. Regardless of what part of the position or shooting steps we're talking about, consistency is critical!
Quote from: Agrivere on July 11, 2014, 10:09:14 AM
QuoteIt doesn't matter if the sights are level as long as they are consistent.
I think you hit the nail on the head here, especially when shooting at 600 yards. Regardless of what part of the position or shooting steps we're talking about, consistency is critical!
This is true, at one distance, only. But if you shoot at different distances, say 400 yards, 600 yards, and 800 yards, then it won't work unless you adjust both elevation and windage at each distance. The reason is that there is a different amount of come-up at each of these distances. The horizontal error is proportional to "r", the total bullet drop plus the sight height above the bore. There is a different amount of horizontal error for the same amount of cant at these 3 distances, because the bullet drops are different. It is easier just to keep the sights level for UD work, that can occur at multiple distances. That way, you only have to adjust your elevation, only.
misspost
Quote from: Guntuckian on July 11, 2014, 10:32:20 PM
]
This is true, at one distance, only. But if you shoot at different distances, say 400 yards, 600 yards, and 800 yards, then it won't work unless you adjust both elevation and windage at each distance. The reason is that there is a different amount of come-up at each of these distances. The horizontal error is proportional to "r", the total bullet drop plus the sight height above the bore. There is a different amount of horizontal error for the same amount of cant at these 3 distances, because the bullet drops are different. It is easier just to keep the sights level for UD work, that can occur at multiple distances. That way, you only have to adjust your elevation, only.
Thus the need to know your zeroes. I shoot with a cant in sitting and offhand. That makes a difference between my 200 and 300 zeroes of 1.5 minutes (6 clicks) right. I do not have a cant in prone (either slow or rapid). My experience is that it is much more important to keep an upright head position than it is to worry about cant. But because my cant is consistent in offhand and sitting, and I have my zeroes for 200, 300, and 600. The cant doesn't matter.
I could do the same thing at 1000 or 900 or 800 or anyother distance as long as I was consistent. If you watch Tubb's T2k video, you will see him setting up the rifle for his daughter, the sights will be cheated for a cant but won't take away all of that cant. You will see that it is the same with his rifle and then you will watch him shoot 10 after 10 after 10 (with a number of X's for good measure).
If you come to the line at Camp Perry for the P100, NTI or NRA week you will see hundreds of people shooting with varying degrees of cant (mainly in offhand and sitting). It is one of the few ways that you can get the Service rifle in the right place to keep an upright head position. In the match rifle the stock is completely adjustable for length, height, angle and offset, so you don't need as much cant.
Quote from: jmdavis on July 11, 2014, 11:27:05 PM
Thus the need to know your zeroes. I shoot with a cant in sitting and offhand. That makes a difference between my 200 and 300 zeroes of 1.5 minutes (6 clicks) right. I do not have a cant in prone (either slow or rapid). My experience is that it is much more important to keep an upright head position than it is to worry about cant. But because my cant is consistent in offhand and sitting, and I have my zeroes for 200, 300, and 600. The cant doesn't matter.
I could do the same thing at 1000 or 900 or 800 or anyother distance as long as I was consistent. If you watch Tubb's T2k video, you will see him setting up the rifle for his daughter, the sights will be cheated for a cant but won't take away all of that cant. You will see that it is the same with his rifle and then you will watch him shoot 10 after 10 after 10 (with a number of X's for good measure).
If you come to the line at Camp Perry for the P100, NTI or NRA week you will see hundreds of people shooting with varying degrees of cant (mainly in offhand and sitting). It is one of the few ways that you can get the Service rifle in the right place to keep an upright head position. In the match rifle the stock is completely adjustable for length, height, angle and offset, so you don't need as much cant.
How does one shoot a stock M1 Garand with a controlled amount of cant? I find it best to use a target to get it level at mid-range and 600 yards. But, this only works for paper targets mounted to a backer. Do you cant using the target to set the cant?
For an AR-15, with a scope, I use a Scopelevel flip-up bubble level, mounted on the scope tube. I can interpolate the elevations, and adjust the windage only for actual wind corrections for UD work. I have a mil-dot scope for ranging. That way, shooting prone, I control my horizontal errors due to cant being limited. Straight levels keep the cant limited to between 3-5 degrees. I know that curved levels would keep cant to around 1 degree, but that is more accuracy than I need at 600 yards.
-gb
You mount the rifle in the exact same place every single time. You keep your head upright, you have a consistent spot or stock weld, and it works. That's how you insure consistency.
You do not need a level to shoot well in prone at 600 yards. You can see cant. If you have it by accident in prone, you need to adjust your sling. Normally, unintended cant in prone is due to the sling being too tight.
The human eye can detect minute amounts of sight misalignment and it can also detect small angular irregularities. From what I can find, that detection ability is not 3 to 5 degrees but 1'. The same 1' that we use to teach inches minutes and clicks it has been measured to finer than 1' in some cases.
https://answers.yahoo.com/question/index?qid=20111011082520AAxh5rp
Yes, the human eye can detect small resolutions that are about 1 MOA. This comes from the properties of the optical blur size that a retina can detect. And, if there is motion, then 1 MOA per second is usually visually detectable, too, by most humans. Some birds can do considerably better. Wire antennas smaller than about 30 AWG will usually be broken by birds flying through the thin wire. 28 AWG wire will usually last better, as birds can see the wire. Humans detect thin covert antennas whenever it exceeds about 0.7 MOA, but won't see even 28 AWG wires in the air. This is thicker in terms of wires than birds can obviously see.
But, angular rotation detection within 1 MOA of true vertical is not usually detectable by humans in the absence of a plumb line. I haven't analyzed this, but I would be very surprised if it is much below a degree or two.
A straight tube spirit or bubble level is only going to indicate rotation at between 3 to 5 degrees, before the bubble starts to move. A curved bubble level can usually lower rotation before the bubble starts to move to around 1 degree. The inner ear has a similar curved structure.
Experimenting with a straight tube bubble level, mounted to a rifle seems like a logical next step. In casual trials, I was canted more than enough to see a tilt in the straight tube bubble level about half the time when I tried it. I didn't do but a few trials, but I wonder if this is improve-able with practice. Will have to experiment with this, and also do an analysis!
Vestibular sensing is likely more of a factor than optical resolution. Having two functional inner ears is also probably an advantage, too. I will have to think this through!
Thanks, jmdavis!
-gb