Range Report How I Test Ballistic Coefficients-Matrix 175gr

[RemingtonSPS]

I have had time to do some extensive testing now with the Matrix .277 cal 175gr VLD. Here is my rifle info, how i determined bc, and the final results.

<span style="font-weight: bold">THE RIFLE</span>

BAT Action.
27" 5-R Rifled 1-9 twist Benchmark barrel.
270 WSM .180" freebore, .310 neck.
Norma brass seperated by weight and match prepped.
Bullets seperated by Ogive. 2.265" BTO (-.020").
65.8gr H-1000. (very hot)
2,990fps Avg MV, ES 13, SD 5 (Veryfied by two chronographs)
Nightforce NXS 3.5-15x50 NPR1 .25 moa

<span style="font-weight: bold">THE PROCESS</span>

I measured out a perfect 100yd distance target using a 300ft tape measure.
My reticle is set dead level by using a vice at the range. I use a level to set the action perfectly level on the vice.
I set up a plumb bob at 100yds.
With the rifle dead level, i level the reticle with the plumb bob down range. Once the rings are tight and i am confident the scope is level with the rifle, i install and level the anti cant device.
I shoot 3 shot groups at the measured hundred yard target, first to zero, then i dial up 20 moa and shoot another 3, then up 40 moa and shoot the last 3. I measure the distance between the groups
with the reticle and then a tape measure to make sure my rifle is tracking level and accurately.

I used the Gseven ballistic engine and the Shooter ballistic engine to verify the data because they agree with each other perfectly. I used the same target board and backed up for each extended distance.
Knowing that i have a sub 1/4 minute load, perfect 100yd zero, and a scope that tracks perfectly, i feel confident in the measured results. Ranges were measured with a Gseven BR2 Rangefinder 3 times each for
accuracy. The target was a large 4'x4' pylwood stand covered in white butcher paper.
My shooting spot is in the bottom of a canyon with a 3mph head wind. It is almost perfectly North to South so the wind is consistent in both speed and direction.
There is no East to West bearing so there is no Coriolis Effect, making it a perfect site for testing BC with drop.
Distances can be shot out to 1611 yds with almost no angle compensation.

<span style="font-weight: bold">ATMOSPHERICS</span>

82F
29.1 HG
600F
50% RH

Here are the ranges i shot, adjustments i used on the dial, and the measured distance from the group average to the point of aim. I like to shoot as close to the edge of supersonic as i can get so that i have a good average BC. These are the inputs i used in the Gseven ballistic engine and used the "True Bullet BC" option. I used a ProChrono that has a history of accuracy, and the Magnetospeed. They agreed within a couple of fps with each other so i did not true the velocity, only the BC.



458yds
7.25 MOA on the dial
+2" high

866yds
19.25 MOA on the dial
+8.5" high

1240yds
34 MOA on the dial
+9.18" high

<span style="font-weight: bold">THE RESULTS</span>

My lot of Matrix bullets measure 1.49" in length with an average Meplat diameter of about .060".
Average BC with a MV of 2,990fps
G7 BC=<span style="font-weight: bold">.3225</span>
G1 BC=<span style="font-weight: bold">.6435</span>

 

[steve123]

Re: How I Test Ballistic Coefficients-Matrix 175gr

Interesting info MuleHunter.

I suspected that the estimated BC's for their .277/175G weren't as high as they advertised. Still pretty good though and higher than the standard 6.5/140G BC's are.

 

[Woodlanddude]

Re: How I Test Ballistic Coefficients-Matrix 175gr

Coriolis is maxed going n/s, not negated. Eotvos effect comes into play E/W at extended range as well. No perfect system for this. Just proves that the effects at closer ranges are inside the human error range for you in this case.

 

[RemingtonSPS]

Re: How I Test Ballistic Coefficients-Matrix 175gr

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Woodlanddude</div><div class="ubbcode-body">Coriolis is maxed going n/s, not negated</div></div>

Thats interesting. I would think with the Earths rotation it would show up as windage shooting N/S which is not part of the equation when determining BC based off of drop. When shooting E/W the theory is that it shows up in a change in elevation. I try to get as accurate a BC as possible to the limits of the bullets subsonic flight. The system I use has been very accurate to 1400yds which is the effective limit of my current equipment and practice.

 

[tobias]

Re: How I Test Ballistic Coefficients-Matrix 175gr

When you shoot North to South you only get windage to the right. The same with South to North (again only to the right!). No elevation. Firing in any direction (at a fixed latitude) gives the same horizontal drift.
When firing to the East Coriolis counteracts gravity and causes the bullet to strike slightly higher. Firing to the West Coriolis reinforces gravity and the bullet strikes lower.

 

[RemingtonSPS]

Re: How I Test Ballistic Coefficients-Matrix 175gr

Thats what I thought which is why I chose that N/S shooting spot for testing BC with drop.

 

[tobias]

Re: How I Test Ballistic Coefficients-Matrix 175gr

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MuleHunter</div><div class="ubbcode-body">Thats what I thought which is why I chose that N/S shooting spot for testing BC with drop. </div></div>

Correct!

 

[spinlite]

I have had time to do some extensive testing now with the Matrix .277 cal 175gr VLD. Here is my rifle info, how i determined bc, and the final results.

<span style="font-weight: bold">THE RIFLE</span>

BAT Action.
27" 5-R Rifled 1-9 twist Benchmark barrel.
270 WSM .180" freebore, .310 neck.
Norma brass seperated by weight and match prepped.
Bullets seperated by Ogive. 2.265" BTO (-.020").
65.8gr H-1000. (very hot)
2,990fps Avg MV, ES 13, SD 5 (Veryfied by two chronographs)
Nightforce NXS 3.5-15x50 NPR1 .25 moa

<span style="font-weight: bold">THE PROCESS</span>

I measured out a perfect 100yd distance target using a 300ft tape measure.
My reticle is set dead level by using a vice at the range. I use a level to set the action perfectly level on the vice.
I set up a plumb bob at 100yds.
With the rifle dead level, i level the reticle with the plumb bob down range. Once the rings are tight and i am confident the scope is level with the rifle, i install and level the anti cant device.
I shoot 3 shot groups at the measured hundred yard target, first to zero, then i dial up 20 moa and shoot another 3, then up 40 moa and shoot the last 3. I measure the distance between the groups
with the reticle and then a tape measure to make sure my rifle is tracking level and accurately.

I used the Gseven ballistic engine and the Shooter ballistic engine to verify the data because they agree with each other perfectly. I used the same target board and backed up for each extended distance.
Knowing that i have a sub 1/4 minute load, perfect 100yd zero, and a scope that tracks perfectly, i feel confident in the measured results. Ranges were measured with a Gseven BR2 Rangefinder 3 times each for
accuracy. The target was a large 4'x4' pylwood stand covered in white butcher paper.
My shooting spot is in the bottom of a canyon with a 3mph head wind. It is almost perfectly North to South so the wind is consistent in both speed and direction.
There is no East to West bearing so there is no Coriolis Effect, making it a perfect site for testing BC with drop.
Distances can be shot out to 1611 yds with almost no angle compensation.

<span style="font-weight: bold">ATMOSPHERICS</span>

82F
29.1 HG
600F
50% RH

Here are the ranges i shot, adjustments i used on the dial, and the measured distance from the group average to the point of aim. I like to shoot as close to the edge of supersonic as i can get so that i have a good average BC. These are the inputs i used in the Gseven ballistic engine and used the "True Bullet BC" option. I used a ProChrono that has a history of accuracy, and the Magnetospeed. They agreed within a couple of fps with each other so i did not true the velocity, only the BC.



458yds
7.25 MOA on the dial
+2" high

866yds
19.25 MOA on the dial
+8.5" high

1240yds
34 MOA on the dial
+9.18" high

<span style="font-weight: bold">THE RESULTS</span>

My lot of Matrix bullets measure 1.49" in length with an average Meplat diameter of about .060".
Average BC with a MV of 2,990fps
G7 BC=<span style="font-weight: bold">.3225</span>
G1 BC=<span style="font-weight: bold">.6435</span>

I realize this is an old Post, but was wondering if you ever tested the matrix 165g in .277