Need help with 2285 yard shot.

[4xforfun]

On my hunting gun (actualy taped on the scope...NSX 8-32) I have the moa dialups from my 300 yard zero up to 1500 in 25 yard incruments. I also have the wind in 5 mph incruments (5 -30 mph full value) to 1500 in 100 yard incruments. I also have a drawing of the retical (np2r) with TWO vertical lines. On this I use the standard (2MOA hash marks) holdovers for 22x on the left of the left line, but I also use 3 MOA (between the two vert lines) at 17.5 and 4 moa at 11x (on the right of the right vert line). This is for simple holdovers from my 300 yard zero.


Then, somewhere in my gear I have another copy of the retical drawing with the 3 different MOA values, but............this one is from a 1500 yard zero.....gets me out way further than I have shot to date. I was going to use it at the mile shoot at the IBS 1k nats in OHIO in 08, but I got there with simple dialups.

It all sounds way more complecated and cluttery than it really is. There is lots of room on the scope when you have the 4" sunshade. BUT.........I found this year that I need to use bigger fonts to be able to see them. Somehow I aged enough to the point where I need reading glasses. WHO's FRIGGEN BRIGHT IDEA WAS THAT????

I guess my point is that, although I have not used the 1500 zero + holdovers yet ( I spend the bulk of my shooting time now days with my 1K comp guns) , It would be no different with a 300 yard zero or a 1500 yard zero. I have tested the 22x, 17.5x, 11x holdovers with the 300 yard zero........it is simple math and it works!!!!

Good luck and have fun!!

 

[nfhjr62]

So when is the shot and we all want to KNOW WHAT HAPPENED

 

[Buffalobob]

I have tested the 22x, 17.5x, 11x holdovers with the 300 yard zero........it is simple math and it works!!!!

The point is well made. Back before there were laser rangefinders and one had to use the reticle, the first thing one did was calibrate the reticle to verify that when the power setting said that you were subtending 18 inches that the reticle actually measured 18 inches.

If one wishes to use the data from the shot for future shots then it will be necessary to ensure that when the power dial says you are at 11X that it is actually 11X and not 10.6X or 11.3X.

 

[4xforfun]

The point is well made. Back before there were laser rangefinders and one had to use the reticle, the first thing one did was calibrate the reticle to verify that when the power setting said that you were subtending 18 inches that the reticle actually measured 18 inches.

If one wishes to use the data from the shot for future shots then it will be necessary to ensure that when the power dial says you are at 11X that it is actually 11X and not 10.6X or 11.3X.

I should re-phrase.......I have tested.....but not at "ultra" LR. I have used it on shorter ranges......say out to 8-900 yards.....where the 10.6 or 11.3 thing is not as critical!!!! When the range gets waaaaaayyyyy out there things need to be EXACT.

Good point Buffalobob!!

 

[theodore]

So 5.5x @ 2285 yards is same as open sight @ 415.45 yards?

 

[4xforfun]

So 5.5x @ 2285 yards is same as open sight @ 415.45 yards?

Please.....no more math for me.........my head hurts.

If you say so.

 

[3fingervic]

This is way out of my league. I just want to hear/see the results. Good luck, keep us posted.

 

[Topshot]

I have everything all sorted out and will be going out in the morning at first light to try this shot.

Just need the wind to play the game and be calm for me. Will post the results when I get back.

 

[Eaglet]

Will Definitely be interesting!

 

[Topshot]

I got up this morning and went out to the location just on day light for my first attempt at this distance with my .338 Edge. Short story, 9 shots over an hour, no hits. But got very close and learned a heap.

Bullet 300 gn SMK, M.V. used 2790 fps, This is a good load and shoots very tight in elevation at 1000 yards. Temp was 14 deg C, pressure 994 mb, wind about 5mph? coming from 5 o'clock.

First lesson. My version of Exbal for PDA doesn't work past 2000 yards so had to use Exbal P.C. version and also JBM ballistics.
Decided to go with the Litz, G7 data which seemed to work in quite well. (There is about 5 MOA of difference between Litz G7 drop data and Sierra G1 drop data at this range). Using G7 data gave me a figure of 120 MOA elevation. And I used "Point Mass" to get Coriolis and Spin drift data of 44" right drift.

The first shot, I dialed in 50 MOA on the elevation turret to avoid the extreme end of the scope travel adjustment. Doing this would also give me some room to move if I needed it.

No input for wind or drift as I hoped they might cancel each other out. I then set the scope at 5.5 power and held 2.5 segments above the bottom of the vertical line on the R1 reticle. This gave me 120 MOA in total. See photo. (Camera is tilted not scope)

I fired the first shot with a clean cold bore and waited the 4.6 seconds for the bullet to get to the target. This is a long time! And I was amazed that I could actually see the dust fly from the bullet impact, even on 5.5 power. I was also amazed that the bullet actually landed very close to the target! Impacting spot on for level with the target but about 3 MOA left.

I then dialed 3 MOA right and fired two more shots. Both these shots landed just left of the target but about 2 MOA over the top.

I then let the barrel cool for a while and dialed down 1 MOA lower. A three shot group followed with two bullets just going over the target and one falling about 10 yards below the target. I then drove up to the target to see what was going on.

After looking at the impact points I had two thoughts. (1) That I needed to shoot a bit lower and (2) that maybe the bullets were not going through the trans sonic barrier too well.

I then went back to the start, by this time the breeze had dropped a bit but I decided to ignore that as it was switching a bit as well. I then dialed down another 1 MOA and fired another three shot group.

One went just over the target, one was level with the target but just right and the last fell in line with the target but just low.

Conclusions. 118 MOA seems to be the drop I need. Litz G7 data is a bit closer to the mark than the Sierra G1 B.C.
The bullets that land high seem to group well together but any that land low could land anywhere. i.e. Some bullets seem to be becoming unstable as they go sub-sonic.
2285 yards is a bloody long way when shooting on 5.5 power.
I need to try this again as it is a lot of fun.

Photo below. At first light, waiting for enough light to shoot.

 

[Buffalobob]

I need to try this again as it is a lot of fun.

Yes it is!!!!

 

[3fingervic]

That was cool. Thanks for sharing. When you going out again?

 

[bigngreen]

That so awesome, sure looks fun . We have found when shooting LR BPCR that when the bullet is on the edge of stability most will be in a group then a few will flop low. Some times we can push them just a little faster or get a faster twist and they will straighten out.
I re-entered the data into my PPC with Loadbase 3.0 and got 118.5 for the come up, so it's close.

 

[MontanaRifleman]

Great pics and report Topshot! It sound to me like you're seeing sub sonic destabilization with some bullets. I'm showing your bullets transitioning at about 1700 yds. I'm wondering if you might be able to set up a target at that range and fire a few to see what happens?

Great stuff! Keep us posted. Makes me wanna get out there and fling some lead gun)