4xforfun
Well-Known Member
It wasn't a 3.8 inch group. It was a 3.8 inch AGG for the weekend. And ...to this day, that load in that BBL produces a crappy ES.
Just sayin.
300 wm 200 gr Berger hybrid retumbo?? Little advice needed
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It wasn't a 3.8 inch group. It was a 3.8 inch AGG for the weekend. And ...to this day, that load in that BBL produces a crappy ES.
Just sayin.
To me, that means his largest group was probably in the 5 to 6 inch range and the smallest 2 to 3 inches. Quite normal for several 5-shot groups to do that at all ranges.
Regarding the 40 fps velocity spread; that bullet has about a 9 inch drop difference. With positive compensation, they'll all strike the same place. With bullets leaving on the muzzle axis up swing, faster ones leave sooner, slower ones leave later. The barrel does not stay still while bullets go through it. It whips and wiggles a lot. The muzzle axis does not point to someplace on the target above the point of aim equal to sight height plus bullet drop until the bullet exits. While aiming, it points somewhere else. Depending on the center of mass of what holds the barreled action (stock, sights, and human) the barrel will whip and wiggle quite a bit at its resonant and harmonic frequencies in some direction until the bullet leaves 1 to 1.5 milliseconds after the round fires.
Here's a software page from Border Barrels to show the principals of how that works.
Barrel vibrations
Pick a barrel contour and load, then run the program with 1/10th inch increments of center of mass below the bore axis starting at zero. Note how the bullet leaves at higher angles as the mass center offset increases.
Ok. Again, would you say this is typical? Is it good advice then to ignore ES for the rest of us who notice it correlates to vertical stringing?
I have an off the shelf remington 700, bone stock, that will routinely shoot into the .2s, and truthfully im not that great off the bench. However, I understand that isnt typical, and wouldn't recommend to someone that who needs a quarter moa rifle to go buy an off the shelf factory rifle and expect the same results.
Anyway, good shooting. I wish my rifle would compensate for ES too!
4xforfun
Well-Known Member
Ok, just clarifying, I apologize if I read too much into what you were saying. They are both important, which is what i have been saying all along. I bring it up because there are plenty of shooters who load develop on group size only, then record drops to get velocity data to input into their ballistic programs. In fact, most hunters I know dont even gave a chronograph.
That can lead to inconsistent results, and Im trying to get more shooters to recognize the importance of their velocity data. I think it is one of the main reasons I see people making lots of adjustments to BC in their programs and otherwise having a hard time making their real world data fit the program-their data points dont line up because of inconsistent loads. If you spend time getting accurate, and consistent, velocity data then the various ballistic programs are remarkably accurate.
This leads to the first round hits that are critical for long range hunting.
In any case, a 3.8 agg is amazing shooting, really. There are some talented people here for sure, and you obviously know what you are doing. I was just pointing out that it is not the norm to shoot long range groups of that size with 40 fps spreads, and that others should not expect to duplicate thise results. Obviously, something else, such as what Bart pointed out, is compensating for it.
That can lead to inconsistent results, and Im trying to get more shooters to recognize the importance of their velocity data. I think it is one of the main reasons I see people making lots of adjustments to BC in their programs and otherwise having a hard time making their real world data fit the program-their data points dont line up because of inconsistent loads. If you spend time getting accurate, and consistent, velocity data then the various ballistic programs are remarkably accurate.
This leads to the first round hits that are critical for long range hunting.
In any case, a 3.8 agg is amazing shooting, really. There are some talented people here for sure, and you obviously know what you are doing. I was just pointing out that it is not the norm to shoot long range groups of that size with 40 fps spreads, and that others should not expect to duplicate thise results. Obviously, something else, such as what Bart pointed out, is compensating for it.
4xforfun
Well-Known Member
Yep.....I have 4 chronographs . ES is has always been a big deal. But, I didn't see where he had shot the 1/4 moa load with the crappy ES at long range to test......thus...my comment. Sometimes what is...well...is!!!
