Range Report Missing Data on range card. Fill in the blanks!

[Sebben]

I was reading another thread about battlefield zero and this got me wondering if this is what my problem was caused by. Other Thread. Or if it was caused by shooting at a down hill angle.

With my rifle zeroed at 100 yards I attempted to engage 1 steel swinger at all previously ranged distances(ranged with mils) using hold overs in only 20 rounds (1 mag). 10 targets so 2 rounds per wouldn't be so bad. Great if ya tag it first shot cause you have more to spare! I hit everything except targets 6 and 7 which were at the bottom of the hill. 7 was obscured by grass so I couldn't get a range but if I had to guess it would be around 530 yards.

My hard dope range card for this one particular range reads as follows. Note: did not shoot at 100 yards.

Yards......Mils (308 win 168 SMK)
100........0.00 (Zeroed on level ground)
185........0.00 (down hill)
277........1.3
333........1.5
392........2.1
476........3.2
530~.......?.?? (#6)
592........?.?? (#7)
654........5.4
686........5.7
727........6.6


Can anyone explain why Targets 6 and 7 did not follow the regular drop? here is a picture of the range hope this helps. The targets are at the bottom of the slope where the trees narrow.

Gun site hills GA.

 

[TackDriver13]

Re: Missing Data on range card. Fill in the blanks!

Too many variables to give you an answer. If you have a smart phone get a ballistic software app that has an angle indicator built in, then you can have perfect data every time.

 

[gstaylorg]

Re: Missing Data on range card. Fill in the blanks!

Any indication of what direction you actually missed on those two?

 

[jbailey]

Re: Missing Data on range card. Fill in the blanks!

I bet 3.7mils would have stung the 530yd target and 4.6mils would have done the 592yd. I'm also guessing your muzzle velocity is 2645fps. I also bet you were a tad low on the 185yd, maybe 3"...

No way does the look angle have anything to do with this ballistic solution, nor are the environmentals.

 

[Sebben]

Re: Missing Data on range card. Fill in the blanks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gstaylorg</div><div class="ubbcode-body">Any indication of what direction you actually missed on those two? </div></div>

Oh yeah. They were high. Just couldn't tell how high. It was hard to see bullet impact due to the tall grass at the target. I migh just have to throw rounds at it until i get a hit. I know it was higher than soft dope for the 592. That should be a 4.5 mil hold but it's not for some reason. I think it's around 3.8. All the targets that were engaged followed soft dope to within .2 mils except for 6 and 7. Wind was not a factor. We had very light 0-5 no value wind. The trees offer excellent cover.

 

[Sebben]

Re: Missing Data on range card. Fill in the blanks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JamesBailey</div><div class="ubbcode-body">I bet 3.7mils would have stung the 530yd target and 4.6mils would have done the 592yd. I'm also guessing your muzzle velocity is 2645fps. I also bet you were a tad low on the 185yd, maybe 3"...

No way does the look angle have anything to do with this ballistic solution, nor are the environmentals.
</div></div>

At the 185 target it was dead bang on the cross hair from my 100 yard zero.

 

[Neo]

Re: Missing Data on range card. Fill in the blanks!

There is no way that you POI is the same at 100 and 185. Even with a muzzle velocity of 3400 fps you would need .2 mils from your hundred yard zero and with an average load of 2600 fps it goes to .4 mils. So either your 100 yard zero is off or your not seeing the difference( aprox 2.7" ) in POA to POI.

 

[Sebben]

Re: Missing Data on range card. Fill in the blanks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Neoshooter</div><div class="ubbcode-body">There is no way that you POI is the same at 100 and 185. Even with a muzzle velocity of 3400 fps you would need .2 mils from your hundred yard zero and with an average load of 2600 fps it goes to .4 mils. So either your 100 yard zero is off or your not seeing the difference( aprox 2.7" ) in POA to POI. </div></div>

That's what I thought too. At 185 I held .5 to get me on the 6x6 steel but it was .5 over the center hitting the top of the target. It has to be the down hill angle that makes it do that.

 

[timelinex]

Re: Missing Data on range card. Fill in the blanks!

You said you ranged these using your reticle?? That could very well be the problem! There is a reason range finders are used, reticle ranging doesn't have the resolution needed for making a solid dope chart.

 

[gstaylorg]

Re: Missing Data on range card. Fill in the blanks!

If the targets were 6"x6", as you noted there is some play in the drop that you had versus what will still allow you to be on. I ran some numbers using an MV of 2630 fps, 7 degree down angle, 80 degrees, 30% humidity, 505 ft elevation (the last three were the last conditions I had here in SD...I was too lazy to change them). I came up with:

185 - 0.4 mil
277 - 1.1
333 - 1.6
392 - 2.2
476 - 3.1
530 - 3.7
592 - 4.5
654 - 5.4
686 - 5.9
727 - 6.6

These numbers are generally within 0.1 mil of what you listed. So my guess would be that you may have been just a tick high on those two because those are "soft" numbers as you pointed out; just needed to hit the steel, not necessarily exactly dead center. Seems like the most probable reason would be the range estimate was slightly off. Alternatively, is it possible you may have just pulled a couple? How many times did you actually shoot at those two?

 

[Sebben]

Re: Missing Data on range card. Fill in the blanks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gstaylorg</div><div class="ubbcode-body">If the targets were 6"x6", as you noted there is some play in the drop that you had versus what will still allow you to be on. I ran some numbers using an MV of 2630 fps, 7 degree down angle, 80 degrees, 30% humidity, 505 ft elevation (the last three were the last conditions I had here in SD...I was too lazy to change them). I came up with:

185 - 0.4 mil
277 - 1.1
333 - 1.6
392 - 2.2
476 - 3.1
530 - 3.7
592 - 4.5
654 - 5.4
686 - 5.9
727 - 6.6

These numbers are generally within 0.1 mil of what you listed. So my guess would be that you may have been just a tick high on those two because those are "soft" numbers as you pointed out; just needed to hit the steel, not necessarily exactly dead center. Seems like the most probable reason would be the range estimate was slightly off. Alternatively, is it possible you may have just pulled a couple? How many times did you actually shoot at those two? </div></div>

Only the one at 185 was the 6x6 steel the target measurement are as fallows. Also just to reiterate the holds I listed were hard dope. Getting center or very close to center hits on the steel.

Target Height
0... 100 yards not counted
1... 30" (target measured)
2... 22"
3... 24"
4... 24"
5... 24"
6... 30" (obscured by grass)
7... 32"
8... 33"
9... 84"
10.. 55"

On target 7 I sent 4 rounds at it before I moved on to the next. I would hold lower than previous round but still couldn't hit it. The rounds were still going over. This is what I'm trying to figure out. Is why targets 6 and 7 didn't follow the normal curve of drop. It seems like target 7 called for more of a 3 mil hold rather than a 4.5. I guess the only way to find out is to go out again and try it. I also have some hand loads that I'm going to ladder test and recheck my zero at 100 with some FGMMs. Ill keep this thread updated and give some hard dope with targets 6 and 7 in the near future. Ill just bracket it. That's what auto loaders are good for right ha ha!

Also going to crono everything. I think that the FGMMs are around 2600 not 2630. we'll see.

 

[jbailey]

Re: Missing Data on range card. Fill in the blanks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sebben</div><div class="ubbcode-body">
Target Height
6... 30" (obscured by grass)
7... 32"
8... 33"
9... 84"
10.. 55"

On target 7 I sent 4 rounds at it before I moved on to the next. I would hold lower than previous round but still couldn't hit it. The rounds were still going over. This is what I'm trying to figure out. Is why targets 6 and 7 didn't follow the normal curve of drop. It seems like target 7 called for more of a 3 mil hold rather than a 4.5. I guess the only way to find out is to go out again and try it. I also have some hand loads that I'm going to ladder test and recheck my zero at 100 with some FGMMs. Ill keep this thread updated and give some hard dope with targets 6 and 7 in the near future. Ill just bracket it. That's what auto loaders are good for right ha ha!

Also going to crono everything. I think that the FGMMs are around 2600 not 2630. we'll see. </div></div>

Well, targets 6 and 7 are almost 2mils at that range. Something else beyond dope must be going on for you not to hit them. Maybe you are pulling them high because something in your position for those two targets is pulling the buttstock up? Unless those targets are at an extreme angle that we can't see in the photo, the look angle is not significant enough to drive bullet off a 2mil target.

Anyway, let us know the chrono results and get out and reshoot that lane!

 

[Twitch2120]

Re: Missing Data on range card. Fill in the blanks!

the FGGM's seemed to be somewhere in the 2650 fps neighborhood although the last string of the day ran in around 2580-ish. think the light was a bit off for the chrony.

he missed because he was a bad shot. haha! really though it was hard for me to walk him down as the lighting was off. the low area was shaded and i suspect the light made the bullets seem lower than they were so my corrections of .2 or .3 tenths were off.

the position we shot from drops off about 30 ft in elevation directly in front of the muzzle and continues to drop all the way to target 6 where it comes back uphill rather steeply.

in his defense he did drill a 20 oz gatorade bottle at 727 in 2 shots.

 

[turbo54]

Re: Missing Data on range card. Fill in the blanks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Twitch2120</div><div class="ubbcode-body">the FGGM's seemed to be somewhere in the 2650 fps neighborhood although the last string of the day ran in around 2580-ish. think the light was a bit off for the chrony. </div></div>

Can you expound on this? You were chronoing during the day, and in the late afternoon the same ammo indicated nearly 100fps less than earlier?

Which chrono? What different lighting conditions caused faster/slower readings?

 

[Twitch2120]

Re: Missing Data on range card. Fill in the blanks!

CE Pro chrony. first readings were taken as a baseline of 3 shots, then a few sub loads i worked up, followed by 3 more FGGM. they all registered 2611 being lowest, 2670 something being highest. sun was at our backs, 4pm. the following 10rds were shot at 545pm so the sun was at a lower angle, one round did not register. the 9 shots that were captured ranged from 2511-2580 something. these were out of the same box as the previous 6. either federal has real bad QC or the sun was reflecting funny and causing the timing to be off. i suspect the latter.

sebben did say he felt like he was shooting the last 10 like crap after having been shooting clover leaves all day. the final 10 looked more like a tight 00 buck spread. also had some strange ladder test results but thats a post for a different section