Range Report 55gr M193 / Burris XTR14 LR ballistics?

[JL]

Cheers,

Was shooting with my 16" carbine. I´m using Burris XTR14 with ballistic reticle.

Got hash mark positions as MOA/mil from Burris webpage- but for some reason I had to use 500meters calculated aiming point for 600meters target.
In another words, aiming point I was using was just above 4th hash mark looking from top.
According to Burris pic/chart I attached, it would be about 5.1mils dope (roughly 16-17MOA) with 100meters zero.

Only two explanations I can come up with would be that 0.120 G7 is pessimistic or given hash mark <span style="text-decoration: underline">dimensions</span> (by Burris) are wrong. Instead, given (yds) ranges seem to match true path nicely, since 4th hash from top is 700yds with 62gr M855- thats 640meters. Since I had to aim, say one line thickness above that fourth hash, it would make about 610-620 meters aiming point with M855.
And target was exactly 600 meters range so it makes sense.

MV:s were measured with Oehler 35P, and my chart was spot on.

In any case, M193 works surprisingly well- even in moderate 11-13mph wind constantly changing from 12 to 9.


Any ideas what is wrong? Anybody here who has checked reticle dimensions or shoot M193?


Here´s dimensions- I´m using 556 reticle.

 

[Rafael]

Re: 55gr M193 / Burris XTR14 LR ballistics?

I am a bit confused by your description when you say the fourth hash is for 500 yards and later say it is for 700.

There are multiple reasons why it could be wrong in this case.
1-This is not an FFP reticle so you must find the exact power setting that yields the subtensions listed. You cannot be sure until you verify this.
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/

2-The conditions must be identical to the conditions the reticle was designed for.

 

[ChadTRG42]

Re: 55gr M193 / Burris XTR14 LR ballistics?

I use 2 of these scopes, and know them well. Burris uses the 62 grain bullet at 3000+ fps for this reticle. If you change the bullet and/or speed, you will have to alter your holds for this reticle. I run the 60 grain V-max and 68 grain BTHP for these reticles. I have a drawing I hand made that shows my hold overs for these 2 bullets on the Burris drawing. You will probably need to do the same thing. Once you know your holds, it's simple to get good hits at distance. In a 16", you won't get the stated velocity with the 62 grain. Hope this helps!

Chad

 

[JL]

Re: 55gr M193 / Burris XTR14 LR ballistics?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rafael</div><div class="ubbcode-body">I am a bit confused by your description when you say the fourth hash is for 500 yards and later say it is for 700.

There are multiple reasons why it could be wrong in this case.
1-This is not an FFP reticle so you must find the exact power setting that yields the subtensions listed. You cannot be sure until you verify this.
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/
</div></div>

Sorry- edited question few times, I was trying to make myself clearer...

Since I´m metric -and reticle works with yds...well...you guess rest.


Anyway, according to MOA hash mark positions in Burris manual:

- third hash is 3.96 mils
- fourth 5.35 mils
- fifth 7.07 mils

G7 0.120 BC with measured 3084fps in shooting day temp and air pressure says:

- 500 meters 4.1 mils (bit below third hash mark)
- 600 meters 6.4 mils (about half way between fourth and fifth hash mark)

But true aiming point where I was able to hit 600 meters target was above fourth hash -in about 4.6 mils accordingly to Burris MOA dimension chart- and it shouldn't be so if BC is ok and given MOA dimensions are correct.


In another hand, as I was trying to explain, if looking only given <span style="text-decoration: underline">yds</span> ranges in Burris manual- fourth hash is 700yds/640 meters. Since aiming point was slightly above it, in about 620meters- it is correct or very close atleast.
That 20 meters range difference is in a ballpark what difference between M193 and M855 should be. Target was exactly at 600meters- Measured with various lasers.

So - because yards match and MOAs doesent- I was thinking that given hash mark <span style="font-style: italic">dimensions</span> might be wrong -and ranges correct.
Or, if hash mark MOA dimensions are correct- then 0.120 G7 BC must be wrong as well as Burris reticle values in yards.

 

[ChadTRG42]

Re: 55gr M193 / Burris XTR14 LR ballistics?

what was your velocity? I don't see it listed.

 

[JL]

Re: 55gr M193 / Burris XTR14 LR ballistics?

From previous post,
"G7 0.120 BC with measured 3084fps in shooting day temp and air pressure says: "

Rifle is 16" carbine.
I guess I´ll have to check reticle dimensions with test table.


P.S.
Sorry for confusing posts...my English is simply not good enough.

EDIT
Just noticed this:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rafael</div><div class="ubbcode-body">
1-This is not an FFP reticle so you must find the exact power setting that yields the subtensions listed. You cannot be sure until you verify this.
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/</div></div>

XTR14 is FFP.

 

[Rafael]

Re: 55gr M193 / Burris XTR14 LR ballistics?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JL</div><div class="ubbcode-body">From previous post,
"G7 0.120 BC with measured 3084fps in shooting day temp and air pressure says: "

Rifle is 16" carbine.
I guess I´ll have to check reticle dimensions with test table.


P.S.
Sorry for confusing posts...my English is simply not good enough.

EDIT
Just noticed this:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rafael</div><div class="ubbcode-body">
1-This is not an FFP reticle so you must find the exact power setting that yields the subtensions listed. You cannot be sure until you verify this.
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/ScopeChecking/</div></div>

XTR14 is FFP. </div></div>

No problem on the english thing..........just don't try to get me to speak your native language.

I think you are wrong about this being an FFP reticle.
If you look at the chart you posted at the top of this thread, it says the 4X is calibrated at 4X and the 6X at 6X.
This means it is not an FFP reticle, and that precise power setting is critical to correct reticle subtension.