Question/Advice about an elevation correction

klink1983

klink1983

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Ontario Soviet Socialist Republic
Givens:
-Rem 700AACSD .308, muzzlebrake, choate tactical stock, Vortex HST Viper 4-16x44 in MRAD (second focal plane)
-Norma 168gr Match, FedGMM 175gr
- "Mystery Handloads:" - 168 or 178gr Amax, ?? grs of either H4895 or IMR4895, OAL of 2.83", WLR primers I think (I negletcted to record what these handloads were.

So I started shooting yesterday with a rifle that I thought was 0 to 100m, it wasn't, I had to come up 6 clicks to get dead centre....all was good.

I tried a few different rounds both factory and "mystery handloads" at 200m, also with fantastic success using iStrelok to help with the elevation correction at 200m; one jagged little hole.

I opted to shoot now at 400m, my 0 at 100m was ammended 6 clicks up remember. I dialed in 400m on iStrelok using 175 FedGMM as I have the exact velocity for it out of my rifle. I fired 9 rounds, no hits :( So I dropped my elevation back to my 100m 0 that I previously setup, which got rid of the 6 clicks I added to bring me to the centre of my target. I re-entered my information into iStrelok in the event that I made a booboo. I was now on target, 3-4 inches high, and a bit to the right because of the breeze. My buddy had the same issue with wind. From here, I corrected using my reticle versus adjusting my dials and I was on.

My question to you all: Why did I have to add 6 clicks initially at 100m to get on target, if at 400m these 6 clicks put me off of the target and hitting the lane number marker? In my defence it was a pretty good group!!!

Thanks in advance!
 
info@mysticprecision.com

The actual range to target can have a big effect on impact elevation so it is best to use a measured range or a consistent rangefinder. Then any error is consistent so things can get mapped out better.

being actual 90yds vs 100yds vs 110yds will throw your zeros out... which then keep growing at all the other distances.

As long as the scope works and you have consistent ranging, modern ballistics programs are getting really good at predicting drop. Variations will occur due to ambient conditions and light but close enough to "hit paper".

Jerry
 
I would have thought that after I corrected my 0 to a proper 100m, my 37 clicks would get my on my target at 400m and not 12ish inches high. I cancelled out the 6 clicks I had to add to my 0 to get on at a proper 100m, and then at that point I was on target where I corrected off of my reticle for the wind.

Picture sent, I shredded that "D" sign real good!
 
That was some fine shooting for sure.

Remember the first point in my first post..... Not every scope tracks properly or consistently. You have to confirm what you dial is actually what you get.

Give your scope a good test and see what happens when you turn the dials. I have a few article on my website in the Tech section to help you along.

Jerry
 
The saga continues.....

I was out at one of my spots to shoot last week. I borrowed a range finder from someone at work and re confirmed my zero at 100 metres. I had to come up again as what I did at Eganville from my original zero, so now she is bang on. I have no idea why this happened, since I had thought it was already at 0. No big deal, 10 minutes with an Allen key and another zero stop ring and we will be good to go.

I guess this happened as the bore became dirtier again.
 
Remember that the first cold bore on a dirty barrel may have a different POI vs the next shots. Barrels do what barrels do and you need to tracking how that bullet will fly. Track the zero after you have shoot a few shots and the group has stabilized.

Also, radical changes in shooting position can affect gun recoil/tacking and that will change POI. I am still unsure about the "come up to zero"?

Are you suggesting that shooting at various locations yield a different zero? Or that you are now changing the zero from a setting at the beginning of your shooting but this new zero is different but stable?

Jerry
 
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