600 yard question

[cmshoot]

I’ve got a chrono if y’all wanna get together at some time and run some ammo through it.

 

[GAgunLAWbooklet]

Once I get on paper, each shot will be individually spotted from the pit crew with a 5" contrasting color disc. With the value given, too. I can estimate how many feet or inches I'm off and fine -tune it as the match progresses.

 

[palmettomoon]

What you really need to know for an accurate value:
Environmentals during the time of zeroing the rifle.
actual MV vs temperature.
Bullet BC.
Current Environments.
Scope tracking error.

I used Hornady BTSP 100gr with .386 G1, in a 1 in 9 twist barrel. I set the zero environmentals to be 90 degrees F with a Density Altitude of 2550. I set the zero distance to 200 yards. Using a MV of 2969 ft/s with the same environmentals as the zero, I get a drop at 600 yards to be 11.25 MOA (11.25 translates to 45 clicks using 1/4 MOA per click turret)

RBGC is about 1,300 ft above mean sea level. I double it makes much difference in your calcs though moving from 200 yd zero to 600 yds.

 

[_Raining]

RBGC is about 1,300 ft above mean sea level. I double it makes much difference in your calcs though moving from 200 yd zero to 600 yds.

Not enough to be off the paper. I don't even check my environmentals, but I shoot at Talladega which has unlimited sighters for the first string at 300 and the first string at 600. RBGC does normal rules which I believe is 2 sighters and they do 3 strings at 600 so he won't get a chance to get his feet wet at 300.

OP's problem is he doesn't know what his MV is. He is using a hunting rifle, most likely with a thin barrel and he will be shooting strings of 20. A hunting scope which is not going to track well, it needs a coin to even turn the turret. Chances are its POI will be off just by changing the magnification. I don't see a parallax adjustment either. We don't know if he reloads or not but I am guessing not, in which case his ammo for the match may not be from the same lot as the ammo he zeroed his rifle for. I don't see a bubble level on his scope so he could have a natural cant which will throw off the numbers for his elevation.

Can you have a fun time and do well with a hunting rifle at an F Class match, sure. Can you do it with 0 preparation, eh...

My advice would be to go to Talladega with a friend (a friend who owns a chronograph) on Saturday. Start at 200 and chrono his ammo. Then plug in the adjustment for 300 and see if the turrets track properly. Once he is comfortable at 300, move out to 600 and see how he does. Set the scope at 9x and leave it there. Note, Talladega will be very busy on Saturday with their D Day competition going on, I don't even know if their will be room for non competitors.

 

[REDX]

OP you might make it to 600 with 20 rounds of sighters but what will you actually have learned once you get there? With out the basic info do you think that you will be able to replicate it? your data can change in minutes. what are you going to do when a storm rolls in and the humidity jumps, the wind goes ape $H!t and the barometric pressure rises?

Get some good data and do it right the first time.

Old wise man said "failing to plan is Planning to Fail!!"

 

[GAgunLAWbooklet]

The rifle shot about 18" low when I'd only gone up 50 clicks from my 200 yd. zero. It was fine after I added a total of 12 more clicks during the next few shots.
When I used an improvised rest front and rear (my range bag under the fore-end, a bath towel rolled and stuffed under the rear of the stock) I was getting mostly 9s and 10's, with more X's than 8's.

Windage required about 4-6 clicks.
The wind was light and generally coming from the front left direction.

When I shot from the unsupported prone position, no sling, my wobble area was about 3 MOA, and my group was about two feet diameter.
The size of a trash can lid.

Ideally, my light profile barrel should be used for 3-shot groups with 5 minutes of cooling time in between, not a 20-24 round "group" fired in 25 minutes in the hot sun.

 

[GAgunLAWbooklet]

P.S. had this been a long range hunting scenario, and I went into the field having never fired this rifle past 200 yards, but relying on Internet data and approximations of similar ammo fired from similar guns, thinking I could make a 600 yard kill on an elk, I would've failed. I wouldn't have taken that elk or moose. I would've shot nearly 2 feet too low.

 

[GAgunLAWbooklet]

my friend shot this with his inexpensive Savage axis in 308 caliber.
His rifle did fine for the first 20 round string, using 168 grain match grade ammo,
but then on the second group of 20 things went straight to hell.
He switched to Remington soft point hunting ammo and his groups opened up, and then by the end of that string he found out that his scope had come loose at the mounts. Some of his shots missed the target backing cardboard completely-- and that's about 8 feet tall and 6 feet wide.
That plastic magazine for his Savage Axis rifle also kept falling out having shaken loose under recoil.
Even though he wasn't loading any rounds into the magazine; he was single loading for each shot instead.

 

[JFM33]

Congrats on getting out there . If you had fun with less then ideal equipment it gets better.
One suggestion now that you have confirmed 600yd zero take the rifle to the range and with a strip of butcher paper (aprox 4' long)make an aim point at the bottom and shoot it at 100yds. This will allow you to have true measure of the actual elevation required.Some scopes don't actually track as advertised,it will also allow you to go to the range before the next match and put the correct elevation. Just rehang the butcher paper and shoot until they match .
John

 

[REDX]

now since you are going to be hooked, you need to purchase my 300 club membership so that you can upgrade at a great deal