Long range load development at 100 yards.

[Erik Cortina]

.

Erik, I am following your topic from Brazil since day one and found it very informative!

My question is: I see that almost all shooters use just one group per load to determine the accuracy of that load in particular. Is it enough?

I saw too many times that a single group does not tell reliable the accuracy (or even the position of the center of the group as based on your method) of a single load.

Would it be better to produce 2 groups of 3 shots on each load, instead of 1 group of 5 shots?

Or in you experience, just one group is enough to point to the right direction?


Thank you very much,

LRCampos.

I see your point, but shooters must know their limitations. When I fire groups I am confident of the results, if I am not, I try again. Keep in mind that I also use and recommend using a chronograph when firing groups. If groups and chronograph numbers coincide, you are on the right track.

 

[Steve Blair]

I see your point, but shooters must know their limitations. When I fire groups I am confident of the results, if I am not, I try again. Keep in mind that I also use and recommend using a chronograph when firing groups. If groups and chronograph numbers coincide, you are on the right track.

[br]
http://www.youtube.com/watch?v=CG2cux_6Rcw

 

[savageshooter86]

Nice Steve

 

[SWThomas]

Erik,

Any advice on my post from the previous page?

Sorry, I missed that one.

I'm thinking somewhere between 45.3 and 45.6. They seem to be pretty similar in relation to the center, they're tight, and the ES SD and AV velocities look pretty good too.

I agree with you, 45.3 and 45.6 look the best. Without knowing what it looks like past 45.6, I would pick 45.5 and test it.

Good luck!

Thanks!

 

[LRCampos]

I see your point, but shooters must know their limitations. When I fire groups I am confident of the results, if I am not, I try again. Keep in mind that I also use and recommend using a chronograph when firing groups. If groups and chronograph numbers coincide, you are on the right track.

Thank you for your answer. I use a chronograph while shooting groups and I too develop my loads at 100 meters since I started shooting rifle.

In my understanding, the development of loads at 100 yards/meters are the first phase, as the second and last phase is the actual use at the desired distance.

Thanks again,

LRCampos.

 

[Minox]

Minox -

Great accuracy and great shooting !.!.!

Since 38.5 is obvious, but yet the starting increment, I would like to see what under 38.5 looks like, and would be great to see what 37.5 to 39.0 would play out like.
Myself I would close the increment up to .3-tenths to refine it down even better with in that found zone.

Donovan

Minox, I agree with Donovan. Based on the target, I would pick between 38.5 and 39.0.

Nice shooting!

Thank you Donovan and Erik I will follow your advices hoping in better results!

bye bye from the Alps/Italy

Sergio

 

[savageshooter86]

Anyone have target of a load worked up then re shot the "window" after doing seating depth test? Seems to me it would change after doing seating depth test

 

[Erik Cortina]

Anyone have target of a load worked up then re shot the "window" after doing seating depth test? Seems to me it would change after doing seating depth test

I have done it, but I would have to dig up the targets. It does not change, why would it?

 

[savageshooter86]

wouldn't seating depth change pressure which would shift the node?

 

[SWThomas]

Anyone have target of a load worked up then re shot the "window" after doing seating depth test? Seems to me it would change after doing seating depth test

I have done it, but I would have to dig up the targets. It does not change, why would it?

If changing seating depth does not change anything, why change seating depth at all? Or am I reading your response wrong?

 

[Raythemanroe]

I would guess if you went from jump to jammed it would alter the pressure therefore changing your node..

 

[Erik Cortina]

Anyone have target of a load worked up then re shot the "window" after doing seating depth test? Seems to me it would change after doing seating depth test

I have done it, but I would have to dig up the targets. It does not change, why would it?

If changing seating depth does not change anything, why change seating depth at all? Or am I reading your response wrong?

Yes, you are reading it wrong.

 

[Erik Cortina]

wouldn't seating depth change pressure which would shift the node?

Ok, my previous answer was the short answer. Allow me to expand on it. The correct answer would be, it depends.

The reason I say that nothing would change is because I advise to find a wide powder node and load to the middle of it. I also recommend that you test at Jam - 0.020" and fine tune seating depth by going from Jam - 0.010" to Jam - 0.030" in 0.003" increments. Therefore, the most you will be off from the mean is .010". So, the slight pressure changes that seating depth causes will no be large enough to put you outside the wide powder charge node that we selected on step one of the tuning procedure.

If you go from jump to hard jam, or vice versa, all bets are off. At that point I would recommend to do a powder test again to isolate the node.

I hope that made sense.

 

[Mr. Ten-X]

Did a 100yd ladder test yesterday w/200 Hybrids and found a flat area of 4 consecutive groups in 3/10th gr increments. Final group had ES of 6. Loaded and tested at 1000yds from the bipod today. The system works.

 

[Erik Cortina]

Nice shooting!

 

[ShootDots]

The vertical on that target look VERY IMPRESSIVE!! Excellent load / shooting!

 

[Steve Blair]

I guess we know what Grant will be shooting at Berger.

 

[Mr. Ten-X]

Yeah, may have to give that one a workout in a couple of weeks

Funny how this 9/8-pitching tomato-stake suddenly started holding elevation when I decided not to clean it at all. Grant has finally pulled his head out and has seen the light.

 

[trailrider121]

On my last outing I ran a test at 325 yards with charges from 65.0 to 66.2grs, and 65.6 through 66.2 had 5/8 to 3/4" vertical and all shared same POI. So my next test was to try Erik's method of seating depth at 100 yards in .003" increments. I've never really tested in that small of movements before, and usually tested in .005" increments. I must say I was impressed with the results.

Wind was blowing from left to right around 3-5 mph. I used wind flags, but no Chronograph.

Here are the results:

-.010"
-.013"
-.016"
-.019"
-.022"
-.025"
-.028"
-.031"

 

[Erik Cortina]

Looks like -.019" is the one! Nice shooting!