Chances are that your issue is with bullet dispersion from the rifle itself, not what happens after the bullet leaves the bore. The rifle and the load are the variables that you're having trouble controlling, not the flight of the bullet itself. With the right powder and bullet combination, the .338 LM burns the powder quite consistently, you just have to find that combination and hope that it matches the harmonics of your barrel.
It's possible, not my theory, it's the theory of some of the best shooters in the world-- others theorise it's recoil and barrel harmonics... None of the largebore magums have won the 1000 yard Benchrest comp yet....Originally Posted by helotaxi
Just used my Lapua as a general example...The very best rifles/shooters in the world have the same type issues.
The current world record holder in 1000yd benchrest is a .300WSM.
Weight counts, right? For a given barrel weight, the smaller bore is going to be more rigid. More rigid means less barrel harmonics to deal with and that means less dispersion from the barrel from the getgo. After the bullet leaves the bore, it's purely physics and aerodynamics. Same BC, same velocity, under the same atmospherics means exactly the same flight path.
The large-bore magnums also kick like a mule and since most of the comps don't allow muzzle brakes and limit the weight of the rifles. That limits who's willing to shoot a large bore magnum in long range competition. Trigger time counts. Fatigue matters. A rifle that is abusive to shoot decreases rounds fired before fatigue becomes a factor. That limits practice and makes such a rifle impractical and uncompetitive over a long course of fire.
Last edited by helotaxi; 10-24-2012 at 12:41 PM.
Well, the reason I started this thread about the 270Win is that I already had a one and wondered if it was worth spending money on a 260Rem since there is only .010 difference in caliber. I wondered if I could achieve the same thing with a 270 as I could with a 260. It seems such a tiny difference
(.010)The amswer seems to be that I could or nearly could achieve the same result if I studied and worked at it. But at long distance I may achieve what I want easier and sooner with a 260 from the standpoint of a novice tying to get somewhere..
Way off of the OP:
30 calibers use to rule, and the may again but--
The highest IBS single high score was set by Sally Bauer with a 6-6.5 Lapua Improved http://bulletin.accurateshooter.com/...-score-record/
30 calibers & 7mms make up about 20% of the shooters for 2012
The Overall IBS Grand Champion for 2012 is Mark King shooting a 6mm Dasher
http://internationalbenchrest.com/re...iteHorseNC.php
I think someone was shooting a 338 Norma in the Heavy gun division for the 2012 National Championship, but Heavy Gun was won with a 6mm Dasher
Ballistic programs work off of algorithms and data input, they are "trajectory models" they do not produce empirical data....
Different makes can and do produce different information using the same bullet
Last edited by FUBAR; 10-24-2012 at 01:42 PM. Reason: Left out
However, with accurate data, the algorithms have proven to be amazingly accurate. The problem is that getting accurate data is impossible. Variations in how the bullet leaves the bore will alter the realized BC of the bullet as well. Since no two rifles shoot exaclty the same, everything is "theoretical". Since you can't exactly measure the wind or air density over a 1000yd range, you also can't attribute differences in the outcome to the cartridge, the caliber, the rifle or anything else because you can't isolate the external variables. The good news is that professionals who have the time and resources to test a lot of bullets and loads and measure their performance extremely precisely have done so. Their results have created the models that the algorithms are built on and those models are built using empircal data.
Go with what you want, Mach 2. But before you make the leap, look into .260 and the various 6.5mm variants. I wouldn't want to end up with 2 years of work and a bunch of money that you couldn't get rid of easily. But everybody does things for different reasons, so if that's your game, go with it.
Most importantly - have fun and go shoot!
The sole limitation on the .270 is bullet selection. Even the VLDs from Berger give up a lot of BC to the other calibers because there has never been a demand for long range bullets in .277cal. If you have a .270 already, something to consider would be a 6.5 or 6mm-06 or a .280 AI. They'll take advantage of the long action and get you into a caliber that does have a wealth of good long range bullets available.
Mach2:
I think you might be surprised with what you can do with a .270 now days....
However you will love a .260 in the appropriate configuration for Longrange shooting/hunting-- a lot of theory and practice has went into developing the .260 family into Longrange shooters.
Don't be confused by our rambling arguments, even though there is a direct correlation between bullet weight and BC, that's academic. (visit the Berger link below and make your own decision)
Right now BC and velocity alone does not guarantee you a win...In the IBS Nationals many of the larger calibers .30 & 338 were shooting higher BC bullets with equal or higher velocity than many of the 6mm rifles that scored higher than them. It's the old in theory vs in practice, and in purely sincetific terms it's an anecdotal argument....however it's the same basic argument that supports your .260 decision
http://internationalbenchrest.com/re...iteHorseNC.php
BC in simple terms is mass, diameter, and drag coefficient, here is a link to a basic starting point for the formula(s). It outlines the relationship between SD and Form Factor....
http://en.wikipedia.org/wiki/Ballistic_coefficient
Then move on to Bryan Litz, you can read the articles and decide if you want the book....I highly recommend.
http://www.appliedballisticsllc.com/...files/Book.htm
And if you don't have ballistics program, get one, more than one. Also it's good to understand things like the difference between G1 vs G7, but in general terms use G1 for more round nose designs and G7 for VDL type designs. Note: the previous statement is overly simplified, but that hint will get you started on the path to understanding ballistic models...
Since Bryan and Berger are referenced, I provided a link to Berger target bullets, and it has a nice comparison link for their other bullets.
helotaxi is correct in his statement "all you need to know to calculate ballistic trajectory is velocity and BC" but it's misleading, the program inherently knows data about the weight, SD, and form factor etc. (reference the formula)
In other words the data has already been inputed/stored in the ballistic programs database i.e. a .243 700 BC bullet is a 117 grain DTAC . Even when a custom BC is entered the ballistics program extrapolates the results based on known, stored information.
As helotaxi said weight alone does not matter....
I originally said in simple terms that it's weight, velocity & BC, and it's basically a correct statement....but I admit I could drop the "weight" because I inherently know that the weight falls at the high end of the BC/weight spectrum , if I know the BCThe reverse is not true, knowing the weight, will not provide an extrapolated BC.
Note that in each caliber listed in the Berger Target bullet link, the highest weight bullet is also the highest BC bullet. That's not accidental, it's by design, and in the vernacular "they are the long pointy ones (that's the form factor, formula stuff)
http://www.bergerbullets.com/Product...20Bullets.html
There is no direct relationship between SD and form factor, unless you're using the BC as a constant. SD is nothing more than weight related to the caliber. Form factor is the shape of the bullet. For example, take two bullets of the same caliber with the same form factor, one of monolithic construction and the other a standard copper jacketed lead core bullet. They will have different SD's because of the different densities of copper and lead. As a result they will have a different BC as well.
You can use a program that doesn't know the first thing about the bullet except the BC that you enter and the velocity and it will calculate the trajectory. The weight, through the SD, is captured in as much as it matters in the BC of the bullet. BC is all that matters as far as the bullet itself is concerned. Digging any deeper is really just complicating things.
Read Litz's book. I would say that it is the single best reference out there about what matters written in terms that a lay person can understand.
Last edited by helotaxi; 10-25-2012 at 07:36 PM.
Guys,
This is a quiet reminder that you are way off topic.
Mach2's question appears to have been answered well some posts ago and since then, the discussion has turned to an extremely detailed discussion of the finer points of external ballistics.
I am not against this discussion, but may I gently suggest that if you wish to continue your discussion, you start an appropriate new thread?
I didn't stay at a Holiday Inn express, and I'm not a moderator (or even a replacement referee), but I thought I'd say something before you get jumped on by one.
Thanks
This is not right it has to be the same weight as 10lbs and 10lbs
I started this thread and I enjoyed what was discussed. I learned more in this thread than all the other threads Ive ever read in this entire blog. I used to buy rifles because they had beautiful wood stocks. The next rifle I buy will be due to qualities you cant see by looking at the gun.
I understood his example, here is a link: http://hyperphysics.phy-astr.gsu.edu/hbase/grav.html
Yes it's time to close this thread.
I did not read all of the posts but the ones I did reminded me of a story I told before but It sticks in my mind when talking long range. Several years ago I was on a western trip. We covered a number of states and were coming home thru Wyoming during Antelope season. I saw a large herd of Antelope and stopped along the road to film them. I filmed for several minutes and then heard a shot. I looked all around but did not see a hunter. I did see a doe get hit by the bullet. She just stood there obviously sick. Soon another shot rang out and the doe dropped. I looked around for the hunter and soon he stood up in the sage. He walked to the doe and went back the way he came. I remembered a car back down the road so I turned around and drove back to it. When I got there the hunter was there. He forgot his knife and went back to get it. I got out and talked to him for a while.
He was a local hunter. I asked how far the shot was and he said 732 yds. He said that this was his last tag. He shot his first doe the week before also over 700 yds. I looked at his rifle and it was a .280 Remington with a large target scope. His rifle was a 700 ADL (WalMart special! I told him that the shot was amazing with a sporter rifle. He looked at me and said "this isn't my long range rifle. My long range rifle is the same but in .270".
I did not read all of the posts but the ones I did reminded me of a story I told before but It sticks in my mind when talking long range. Several years ago I was on a western trip. We covered a number of states and were coming home thru Wyoming during Antelope season. I saw a large herd of Antelope and stopped along the road to film them. I filmed for several minutes and then heard a shot. I looked all around but did not see a hunter. I did see a doe get hit by the bullet. She just stood there obviously sick. Soon another shot rang out and the doe dropped. I looked around for the hunter and soon he stood up in the sage. He walked to the doe and went back the way he came. I remembered a car back down the road so I turned around and drove back to it. When I got there the hunter was there. He forgot his knife and went back to get it. I got out and talked to him for a while.
He was a local hunter. I asked how far the shot was and he said 732 yds. He said that this was his last tag. He shot his first doe the week before also over 700 yds. I looked at his rifle and it was a .280 Remington with a large target scope. His rifle was a 700 ADL (WalMart special! I told him that the shot was amazing with a sporter rifle. He looked at me and said "this isn't my long range rifle. My long range rifle is the same but in .270".
Last edited by Tom Brush; 10-30-2012 at 08:53 PM.
I did not read all of the posts but the ones I did reminded me of a story I told before but It sticks in my mind when talking long range. Several years ago I was on a western trip. We covered a number of states and were coming home thru Wyoming during Antelope season. I saw a large herd of Antelope and stopped along the road to film them. I filmed for several minutes and then heard a shot. I looked all around but did not see a hunter. I did see a doe get hit by the bullet. She just stood there obviously sick. Soon another shot rang out and the doe dropped. I looked around for the hunter and soon he stood up in the sage. He walked to the doe and went back the way he came. I remembered a car back down the road so I turned around and drove back to it. When I got there the hunter was there. He forgot his knife and went back to get it. I got out and talked to him for a while.
He was a local hunter. I asked how far the shot was and he said 732 yds. He said that this was his last tag. He shot his first doe the week before also over 700 yds. I looked at his rifle and it was a .280 Remington with a large target scope. His rifle was a 700 ADL (WalMart special! I told him that the shot was amazing with a sporter rifle. He looked at me and said "this isn't my long range rifle. My long range rifle is the same but in .270".
Well the 280 is a great round with great bullets ;-) and might be my next gun but I wounder why savage doesn't have a rifle ni it ??????
That would be an accurate statment. You could or come close enough for practical purposes with the .270 Win but it would most likely be easier with the .260 Rem. The .270 has a very limited choice of long range bullets though and that will make it tougher. Besides, there does seem to be something special about the 6.5s. I do think more shooting time and less computer time would benefit a lot of people.
Last edited by Jamie; 10-31-2012 at 08:29 AM.
Almost no one does. Browning and Winchester do right now. Remington comes and goes. Nosler chambers the Ackley Improved version. Lots of barrel makers chamber for it though and with a Savage, that's all you need
Just thought everyone here would like to know, that among other things, Nosler is releasing a new Accubond long range bullet for the 270 with a BC of .625 according to them:
http://www.noslerreloading.com/phpBB...98d85a30a6b97f
Should make the 270 competitive at long range, if those numbers are true that is.
Nosler is known to use the highest velocity range BC as their advertised number. The real number decreases with velocity and the average will work out in the .60 range most likely. I wouldn't trust it until is was verified and certainly wouldn't attempt a long shot based solely on that advertised number without some real world dope.
Regardless, I'm looking forward to getting ahold of some of them the .270 and 7mm.
Anyone shoot the Woodleigh 180 grain protected point? I'd be interested in how that performs on game.
Except they also listed the G7 BC, which isn't velocity dependent and is still a very high number, but I do know that they have been known to really inflate their BC numbers. The fact that they list a G7 BC to me shows that there might be some truth in the numbers their claiming, but like most other people, I will remain skeptical until the real world numbers come out.
G7 still uses velocity--Drag Functions simplified Drag Coefficients...
G7 is for a particular projectile shape, we want to use the drag function whose BC changes the least over a range of specified/usable velocities
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