Help in sight in

[wbhco2011]

hello...
Load is 4350 IMR @ 2950 fps
200 gr AccuBond
sighted in at 100 to be 4.5 high
dead on at 300 yds.

At 200 yds the bullets are printing at 10" high. Is it the trajectory or am I at fault with poor mechanics on the trigger
at 100 group sub MOA
300 yds 3" group.

need to understand why the extreme variance at 200yds

 

[Guy Miner]

That's pretty wild, 10" high at 200 yards to be "dead on" at 300 yards... Particularly with a nearly 3,000 fps muzzle velocity on a high BC bullet.

Frankly, I don't know. Never ran into that sort of thing before...

How high above the center of your bore is your scope?

Guy

 

[JD338]

wbhco2011

Welcome to the forum.

Need a little bit more information...

What rifle and chambering?

What scope and mounts?

What are you using for a rest?

JD338

 

[wbhco2011]

338
lija barrel 1:10
Leupold 2.5 x10 vx111 ao
set 1.5" off barrel
control mounts
sand bags off bench

 

[Antelope_Sniper]

What's your barrel contour?
How long is the barrel?
Did you chronograph your load, or are you going by the book?
How much H4350, what brass and primer?
Did you use the exact same load, or did you change something minor between the two targets?
Did you change the power on your scope?

 

[SJB358]

With that bullet speed and bullet combo I would guess you should be on the rise and be about 5-6" high at 200. I tend to sight in 3-3.5" high with most of my rifles in that range. Gives me a 250-300 yard zero depending on the cartridge.

Just looking quickly at a ballistics chart, 4.0 high at 100 would make you about 4.7 high at 200 and give you a 300 yard zero and about 11" low at 400. The charts are not right on, but that should be more of the effect of what you are seeing. Sounds like a great combo, I have the same scope on my 338WM rifle. Scotty

 

[wbhco2011]

The lilja contour is 1 1.200" .700" .525" 2.50" 6" 27.0" 2.70 lbs.

I have not chronographed the load

i hand weigh each load

I am unsure of the extreme rise when by all considerations it should be around 5" high but it is printing 10"

I will go back out and set up on the bench and watch my breathing and trigger squeeze and see if that mends the problem.

 

[SJB358]

Good luck, let us know how they work. Hope it corrects itself. Scotty

 

[OU812]

What is the group size at 200? I see your scope has an AO. Is it set parallax free at 200?

 

[Antelope_Sniper]

A number 1 contour in .338 is a very light barrel with a very big hole down the middle of it. I don't imagine it would take much to heat it up. And at 27" it could be pretty whippy.

.525
-.338
=.187
divide by 2
.0935.

That's paper thin for a barrel.

 

[Ridge_Runner]

ok scope is prolly 1,5" over bore center to center, plus your raising the bullet another 4.5 " at 100, thats a total of 6" at 100 yards, if it wasn't beyond the top of the arch you would be 12" high at 200 with no drop.
RR

 

[wbhco2011]

Ridge Runner,

your spot on in yor explanation. I just needed advice from the forum and thus I will reduce my 100yd point of impact to 3 " thus 4.5" and should reduce my 200 yd to some 8 "

 

[Antelope_Sniper]

RR, don't most ballistics programs assume the sites are 1.5" over bore? In addition the .338 WM should hit it's apex right at 150 Yards, so the bullet trajectory should be headed down at 200 yards.

WB, you said you are dead on at 300.
Did you shoot it at 300?

 

[Ridge_Runner]

RR, don't most ballistics programs assume the sites are 1.5" over bore? In addition the .338 WM should hit it's apex right at 150 Yards, so the bullet trajectory should be headed down at 200 yards.

WB, you said you are dead on at 300.
Did you shoot it at 300?

yes, and correct, thats why I said it would be 12" high at 200 if it hadn't reached the top of the arc and started dropping. Is it top of the arc at exactly 150, have no idea, depends on too many variables to determine exactly where the apex is.
RR

 

[Antelope_Sniper]

I usually carry my .338 zeroed for 250, and turn the dials for anything past 300.
Top of trajectory is right at 150 yards.

Trajectory
Input Data
Manufacturer: Nosler Description: AccuBond™ Spitzer
Caliber: 0.338 in Weight: 200.0 gr
Ballistic Coefficient: 0.414 G1

Muzzle Velocity: 3000.0 ft/s Distance to Chronograph: 10.0 ft

Sight Height: 1.50 in Sight Offset: 0.00 in
Zero Height: 0.00 in Zero Offset: 0.00 in
Windage: 0.000 MOA Elevation: 0.000 MOA
Line Of Sight Angle: 0.0 deg Cant Angle: 0.0 deg

Wind Speed: 10.0 mph Wind Angle: 90.0 deg
Target Speed: 10.0 mph Target Angle: 90.0 deg
Target Height: 12.0 in

Temperature: 59.0 °F Pressure: 29.92 in Hg
Humidity: 0.0 % Altitude: 0.0 ft

Vital Zone Radius: 5.0 in

Std. Atmosphere at Altitude: No Pressure is Corrected: Yes
Zero at Max. Point Blank Range: No Target Relative Drops: Yes
Mark Sound Barrier Crossing: No Include Extra Rows: No
Column 1 Units: 1.00 in Column 2 Units: 1.00 MOA
Round Output to Whole Numbers: No
Output Data
Elevation: 5.844 MOA Windage: 0.000 MOA

Atmospheric Density: 0.07647 lb/ft³ Speed of Sound: 1116.4 ft/s

Maximum PBR: 356 yd Maximum PBR Zero: 303 yd
Range of Maximum Height: 168 yd Energy at Maximum PBR: 2207.3 ft•lbs

Sectional Density: 0.250 lb/in²
Calculated Table
Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead
(yd) (in) (MOA) (in) (MOA) (ft/s) (none) (ft•lbs) (s) (in) (MOA)
0 -1.5 *** 0.0 *** 3008.0 2.694 4017.4 0.000 0.0 ***
25 -0.1 -0.4 0.0 0.2 2948.5 2.641 3860.2 0.025 4.4 16.9
50 1.1 2.0 0.2 0.3 2889.9 2.588 3708.2 0.051 9.0 17.1
75 2.0 2.5 0.4 0.5 2832.0 2.537 3561.2 0.077 13.6 17.3
100 2.6 2.5 0.7 0.7 2775.0 2.486 3419.1 0.104 18.3 17.5
125 2.9 2.2 1.1 0.9 2718.6 2.435 3281.7 0.131 23.1 17.6
150 3.0 1.9 1.7 1.1 2663.0 2.385 3148.7 0.159 28.0 17.8
175 2.7 1.5 2.3 1.2 2608.1 2.336 3020.2 0.187 33.0 18.0
200 2.2 1.0 3.0 1.4 2553.8 2.287 2895.8 0.217 38.1 18.2
225 1.3 0.5 3.8 1.6 2500.2 2.239 2775.5 0.246 43.3 18.4
250 -0.0 -0.0 4.8 1.8 2447.2 2.192 2659.2 0.277 48.7 18.6
275 -1.6 -0.6 5.9 2.0 2394.9 2.145 2546.6 0.308 54.1 18.8
300 -3.6 -1.2 7.0 2.2 2343.2 2.099 2437.9 0.339 59.7 19.0
325 -6.0 -1.8 8.3 2.5 2292.1 2.053 2332.7 0.372 65.4 19.2
350 -8.8 -2.4 9.8 2.7 2241.6 2.008 2231.2 0.405 71.2 19.4
375 -12.0 -3.1 11.3 2.9 2191.8 1.963 2133.0 0.438 77.2 19.7
400 -15.7 -3.8 13.0 3.1 2142.5 1.919 2038.2 0.473 83.3 19.9
425 -19.9 -4.5 14.9 3.3 2093.9 1.876 1946.8 0.508 89.5 20.1
450 -24.6 -5.2 16.9 3.6 2046.0 1.833 1858.6 0.545 95.9 20.3
475 -29.7 -6.0 19.0 3.8 1998.6 1.790 1773.6 0.582 102.4 20.6
500 -35.5 -6.8 21.3 4.1 1952.0 1.748 1691.8 0.620 109.1 20.8


Based on that, I think there is something else goin on, Thin barrel that is warming up, change is scope power, ect....

 

[Ridge_Runner]

I usually carry my .338 zeroed for 250, and turn the dials for anything past 300.
Top of trajectory is right at 150 yards.

Trajectory
Input Data
Manufacturer: Nosler Description: AccuBond™ Spitzer
Caliber: 0.338 in Weight: 200.0 gr
Ballistic Coefficient: 0.414 G1

Muzzle Velocity: 3000.0 ft/s Distance to Chronograph: 10.0 ft

Sight Height: 1.50 in Sight Offset: 0.00 in
Zero Height: 0.00 in Zero Offset: 0.00 in
Windage: 0.000 MOA Elevation: 0.000 MOA
Line Of Sight Angle: 0.0 deg Cant Angle: 0.0 deg

Wind Speed: 10.0 mph Wind Angle: 90.0 deg
Target Speed: 10.0 mph Target Angle: 90.0 deg
Target Height: 12.0 in

Temperature: 59.0 °F Pressure: 29.92 in Hg
Humidity: 0.0 % Altitude: 0.0 ft

Vital Zone Radius: 5.0 in

Std. Atmosphere at Altitude: No Pressure is Corrected: Yes
Zero at Max. Point Blank Range: No Target Relative Drops: Yes
Mark Sound Barrier Crossing: No Include Extra Rows: No
Column 1 Units: 1.00 in Column 2 Units: 1.00 MOA
Round Output to Whole Numbers: No
Output Data
Elevation: 5.844 MOA Windage: 0.000 MOA

Atmospheric Density: 0.07647 lb/ft³ Speed of Sound: 1116.4 ft/s

Maximum PBR: 356 yd Maximum PBR Zero: 303 yd
Range of Maximum Height: 168 yd Energy at Maximum PBR: 2207.3 ft•lbs

Sectional Density: 0.250 lb/in²
Calculated Table
Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead
(yd) (in) (MOA) (in) (MOA) (ft/s) (none) (ft•lbs) (s) (in) (MOA)
0 -1.5 *** 0.0 *** 3008.0 2.694 4017.4 0.000 0.0 ***
25 -0.1 -0.4 0.0 0.2 2948.5 2.641 3860.2 0.025 4.4 16.9
50 1.1 2.0 0.2 0.3 2889.9 2.588 3708.2 0.051 9.0 17.1
75 2.0 2.5 0.4 0.5 2832.0 2.537 3561.2 0.077 13.6 17.3
100 2.6 2.5 0.7 0.7 2775.0 2.486 3419.1 0.104 18.3 17.5
125 2.9 2.2 1.1 0.9 2718.6 2.435 3281.7 0.131 23.1 17.6
150 3.0 1.9 1.7 1.1 2663.0 2.385 3148.7 0.159 28.0 17.8
175 2.7 1.5 2.3 1.2 2608.1 2.336 3020.2 0.187 33.0 18.0
200 2.2 1.0 3.0 1.4 2553.8 2.287 2895.8 0.217 38.1 18.2
225 1.3 0.5 3.8 1.6 2500.2 2.239 2775.5 0.246 43.3 18.4
250 -0.0 -0.0 4.8 1.8 2447.2 2.192 2659.2 0.277 48.7 18.6
275 -1.6 -0.6 5.9 2.0 2394.9 2.145 2546.6 0.308 54.1 18.8
300 -3.6 -1.2 7.0 2.2 2343.2 2.099 2437.9 0.339 59.7 19.0
325 -6.0 -1.8 8.3 2.5 2292.1 2.053 2332.7 0.372 65.4 19.2
350 -8.8 -2.4 9.8 2.7 2241.6 2.008 2231.2 0.405 71.2 19.4
375 -12.0 -3.1 11.3 2.9 2191.8 1.963 2133.0 0.438 77.2 19.7
400 -15.7 -3.8 13.0 3.1 2142.5 1.919 2038.2 0.473 83.3 19.9
425 -19.9 -4.5 14.9 3.3 2093.9 1.876 1946.8 0.508 89.5 20.1
450 -24.6 -5.2 16.9 3.6 2046.0 1.833 1858.6 0.545 95.9 20.3
475 -29.7 -6.0 19.0 3.8 1998.6 1.790 1773.6 0.582 102.4 20.6
500 -35.5 -6.8 21.3 4.1 1952.0 1.748 1691.8 0.620 109.1 20.8


Based on that, I think there is something else goin on, Thin barrel that is warming up, change is scope power, ect....

Good catch AS, just ran the numbers through exbal, yes he has 2" too much elevation at 100 to have a 300 yard sight in, so back to square 1
RR

 

[wbhco2011]

Yes I have 3" group off sand bags @ 300yds

I am heading to the range tonight and lowering my 100yd point of impact to 3.5 " then shoot at 200yds and 300yds to see the difference in impact.

FYI

Scope mounts are tight and I only shoot three shots and rest the barrel to reduce heat. I also dry snake the bore after 6 shots

 

[Antelope_Sniper]

Very nice.
I suggest you work out, shoot 100, 200 then 300. Be sure to keep your scope on the same power for all the targets.

 

[wbhco2011]

Range trip completed

reduced POI at 100yds to 3.5 "
result was 5.5 high at 200 yds
1" low at 300 yds

thanks for the advice and direction

 

[Guest]

Try as I might, I can't duplicate that trajectory with a 200gr AccuBond from a 338cal weapon, using my favorite simulator. What I can do is get 4.5" high at 100, 5.5" high at 200, and 1" low at 300yds, if I use 2700fps as the velocity. That's the closest I can get to your observed trajectory, and it's well below your estimated velocity (which wouldn't totally surprise me, just for the record). Very puzzling that the trajectory isn't consistent.