Same! ER/Urgent care
Importance of STD Deviation of velocity with repesct to accuracy?
- Thread starter kujuak
- Start date
Same! ER/Urgent care
internal medicine
Alex Wheeler
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Es does not correlate to accuracy untill it gets real bad. We do not use ES or SD in our tuning for sr br, lr br, or F class. I have seen tons of vertical groups with good es. Especially at 600, dont worry about es if its under 30. 30s not good but it wont hurt you at 600. Es is a tuning thing so long as your loading is good. You can tune for small es or small groups. Some times they line up. Most times they dont.
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wboggs
Gold $$ Contributor
How can a load with a large ES not lead to a large vertical dispersion?
Alex Wheeler
Site $$ Sponsor
Barrel harmonics.
jelenko
Gold $$ Contributor
Indeed!
Some do use muzzle velocity as an input to QL/GRT to get guidance on where accuracy nodes might be.
That said, my perception is some people still tune for small es/sd and some want to see how fast they can make the bullet go.
Equipment and tuned loads are of course important. But if you plan to shoot an animal at those distances, I submit that the limiting factor will be your ability to make a shot in the vital area under field conditions, not off a bench.
I see it all the time, guys spending hours on the bench trying to squeeze a few .1's in load development and never practice or determine their realistic capability to hit the vital area in a simulated field shooting position.
It might be sobering to do some testing by placing a target representing the vital area at varying distances and shooting 3 shots at each distance to the maximum distance you intend to take a shot in the same manner you will shoot in the field.
This is the difference between target shooting and hunting.
I see it all the time, guys spending hours on the bench trying to squeeze a few .1's in load development and never practice or determine their realistic capability to hit the vital area in a simulated field shooting position.
It might be sobering to do some testing by placing a target representing the vital area at varying distances and shooting 3 shots at each distance to the maximum distance you intend to take a shot in the same manner you will shoot in the field.
This is the difference between target shooting and hunting.
Alex Wheeler
Site $$ Sponsor
Theres obviously many reasons to know your velocity. And many still believe that ES has a role in accuracy. However if you shoot a lot of groups on paper at long range you will eventually see that the ES does not correlate to the best groups. In fact most of the time the real small ES groups will be vertical. Its just not a good tool to use. However it can be for diagnosing problems. Like a flier. If it correlates to a odd velocity then that gives you an idea of how to fix it. Before the orange box came out a lot of use would not bother to setup a chrony while tuning, many still dont. It just doesnt matter.
There is accuracy and there is precision. Hitting the point of aim is accuracy, how close multiple shots are to each other is precision. At shorter ranges, at 100yds, the point of impact is primarily governed by the internal ballistics and direction that the bullet is traveling when it leaves the muzzle (where the barrel is pointing and how fast it is moving). Most centerfire cartridges will only move the POI by about 1 caliber for a 100fps change in velocity at 100yds. At 300yds a typical drop for 20 fps is about 1/2 inch or 0.16 MOA (1/2 Click on most scopes). However, differences in velocity ultimately show up in the vertical drop as the time of flight increases.
These values were based on a 308 168 gn bullet trading at 2600 fps. Obviously every cartridge and bullet with vary but a 300 WM is going to be better.
These values were based on a 308 168 gn bullet trading at 2600 fps. Obviously every cartridge and bullet with vary but a 300 WM is going to be better.
Thanks . I am aware of that. I have shot competively for decades in what we call up here service rifle matches until our government decided civilians were not to be trusted with AR-15s.these matches consist of position shooting(prone, kneeling, offhand, with some moving targets) with narrow time windows, I also do alot of bush plinking, shooting small boulders at various distances with my hunting rifles. I have always hunted with factory ammo focusing my reloading on 308 and 223 ammo for matches. In retirement i have branched out to loading for my hunting rifles. I have found this to be a much more complex proposition.For my match rifles I settled on Lapua brass/Berger Juggernaught bullet and Fed Match primers/and Varget powder for 308 and a similar set up in 223. With hunting rifles I find it a much bigger challenge. The rifles are much lighter, thinner barrels and at their best not as accurate as my match rifles in my hands. Bullet choice makes it even more challenging, ballistic coefficients vs bullet construction. Grizzly bears are a major consideration where i hunt (2 confirmed grizzly attacks in my province in the last 2 weeks!) so a stout bullet with 1.5MOA accuracy trumps a non"premium " bullet with 0.5 MOA accuracy. Load development costs also weigh on my decisions. I buy my match bullets in boxes of 500, sometimes several boxes at a time. This retired old fart sure as heck cannot buy Nosler Accubonds, Swift AFrame, or North Fork bullets in such quantities.That is why i want to get to the most accurate load with the fewest rounds fired as possible. So any tricks/tips or insights from experience are greatly appreciated.
L.Sherm
Silver $$ Contributor
I'm with Alex on the E.S and S.D thing. I dont shoot any competion but I do shoot alot of different rifles at 665-700 yards and my 6.5x300wsm waterlines with a E.S of 18fps at 665 both times ive tested the load. 2" wide but completely flat, I would like to stand it up some though.
I've seen single digits E.S. shoot horrible vertical and terrible groups at the distances I test at and some really good.
I run with whatever the target tells me.
I've seen single digits E.S. shoot horrible vertical and terrible groups at the distances I test at and some really good.
I run with whatever the target tells me.
Sounds like you are on the right track. As you know, as a hunter, shot placement and bullet construction is the key to success for hunters.
You shouldn't have any trouble developing a reload that meets and most likely exceeds the performance of factory ammo even though factory ammo is 100% better than when I started in the 60's. I just wouldn't get too bogged down with theories. Developing a high-performance hunting reload, especially for big game is a fairly straight forward proposition at least in my experience. When I missed, even critters with small vital areas such as groundhogs or predators, it wasn't due to the reload, it was me.
I do all most all my range shooting off cross sticks since this is the way I hunt. I have realistic idea of my capabilities, and this builds confidence. Plus, at least for me, this is a lot more fun and is a way to test myself in real world hunting scenarios.
Or if they have their heart medications handy especially if hiking for an hour in the "big woods" of north central PA.
Why would any one do that ?
I use one or two shots per increment during powder testing at one point of aim to identify
nodes and three per increment for seating test.
I do have my Garmin set up but only for general info.
The target is king.
I liked the std comments. I like a smartass comment ever so often. Like Doc says, He reminds me of me. Doug
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