45-70-405 100yd 'Hold Over' for a 200yd target?

[Walstr]

Greetings;
My rifle range is limited to 100yd. I'm developing loads for my custom 45-70-405 cast w/CWW+2% Pewter. It's a broad nosed 73% Meplat designed for 'thumping'.

Right now I'm evaluating 50yd, 5 rnd group'g results with 36gn-46gn IMR 3031. So far NO LEADING - Yahoo! The higher loading's seem to be doing the best in my Marlin 1895 SS Guide, 18" bbl.

When I move to the 100yd range, what "Hold Over" shall I use for a 200yd target? Thanks much.

Wally

[country gent]

With not knowing the velocity of your load its a wild guess but you probably need to hit 4"-6" high at 100 yds to be close at 200yds. Is my guess. My 45-90 with 550 grn bullets dead on at 100 will pass just under the repair center (src) at 200 yds. Thats with a 550 grn bullet at 1350 fps.

[tsubaki]

http://www.hornady.com/assets/snippets/custom/ballistics_calculator/images/print-header.jpg


Your Input Variables

Ballistic Coefficient
0.214
Velocity (ft/s)
1200
Weight (grains)
405


Maximum Range (yds)
200
Interval (yds)
25
Drag Function
G1


Sight Height (inches)
1.5
Shooting Angle (degrees)
0
Zero Range (yds)
100


Wind Speed (mph)
0
Wind Angle (degrees)
90
Altitude (ft)
0


Pressure (hg)
29.53
Temperature (F)
59
Humidity (%)
0.78


Ballistics Results

RANGE(YARDS)
VELOCITY(FPS)
ENERGY(FT.-LB.)
TRAJECTORY(IN)
COME UP IN MOA
COME UP IN MILS
WIND DRIFT(IN)
WIND DRIFT IN MOA
WIND DRIFT IN MILS


Muzzle
1200
1295
-1.5
0
0
0
0
0


25
1154
1197
1.5
-5.6
-1.6
0
0
0


50
1113
1114
2.8
-5.3
-1.5
0
0
0


75
1078
1044
2.3
-3
-0.9
0
0
0


100
1046
985
0
0
0
0
0
0


125
1019
933
-4.3
3.3
0.9
0
0
0


150
994
888
-10.7
6.8
2
0
0
0


175
971
848
-19.3
10.5
3.1
0
0
0


200
951
813
-30.1
14.4
4.2
0
0
0







http://www.hornady.com/assets/snippets/custom/ballistics_calculator/images/print-header.jpg


Your Input Variables

Ballistic Coefficient
0.214
Velocity (ft/s)
1500
Weight (grains)
405


Maximum Range (yds)
200
Interval (yds)
25
Drag Function
G1


Sight Height (inches)
1.5
Shooting Angle (degrees)
0
Zero Range (yds)
100


Wind Speed (mph)
0
Wind Angle (degrees)
90
Altitude (ft)
0


Pressure (hg)
29.53
Temperature (F)
59
Humidity (%)
0.78


Ballistics Results

RANGE(YARDS)
VELOCITY(FPS)
ENERGY(FT.-LB.)
TRAJECTORY(IN)
COME UP IN MOA
COME UP IN MILS
WIND DRIFT(IN)
WIND DRIFT IN MOA
WIND DRIFT IN MILS




















Muzzle
1500
2023
-1.5
0
0
0
0
0


25
1430
1839
0.6
-2.3
-0.7
0
0
0


50
1365
1675
1.6
-3.1
-0.9
0
0
0


75
1304
1528
1.5
-1.8
-0.5
0
0
0


100
1247
1399
0
0
0
0
0
0


125
1196
1287
-2.8
2.1
0.6
0
0
0


150
1151
1190
-7.2
4.6
1.3
0
0
0


175
1110
1109
-13.1
7.2
2.1
0
0
0


200
1075
1040
-20.9
10
2.9
0
0
0

[tsubaki]

Sorry, that was the best I could come up with at the time.
This was assuming a lot of stuff such as the bullets BC and muzzle velocity.
These were based on 1200fps and 1500fps assuming 36gr and 46gr of powder would produce those velocities.

[NSB]

Pretty good figures. Most of my loads are in that ball park. It's no varmit rifle, but they're fun to shoot.

[OnHoPr]

If you are using irons or a peep the drop will be more. The input stated above is with a 1.5" sight height. If you are using a scope and sighted in 1.5" high @100 yds the drop @ 200 yds won't be so severe and you will only be about 2" high or so @ 50 yds.

[Motor]

I simple old ballistics program like "on target" would tell you all you need to know and more. Like how high to sight in for any down range zero. You need your "sight above bore centerline dimension" your ballistic coefficient, and you velocity.

Motor

[Sagebrush7]

My medium loads 300 to 405 grain bullets pushed with 45-50 grains 3031 will scope set 2-1/2" high will give me dead deer at 200 yds. Will ring my 200 yd gong all the time. Not scientific, but works in the high country of Alabama. That is 350' above sea level.

[Walstr]

tsubaki;
Much appreciated. No fps 'cause I shot my chrony---one shot, one kill. That 'sight over barrel' dimension got me, arrgh. When it's replaced, I'll have some good data. Thanks again.

Do I understand then a 21" Holdover @ 100yds, 1500fps, will put me on target @ 200yds?

p.s. Sorry for delayed response == my laptop crashed.

[Artful]

Maybe this will make it easier to visualize

1200 fps


http://www.hornady.com/assets/snippets/custom/ballistics_calculator/images/print-header.jpg


Your Input Variables



Ballistic Coefficient
0.214
Velocity (ft/s)
1200
Weight (grains)
405


Maximum Range (yds)
250
Interval (yds)
25
Drag Function
G1


Sight Height (inches)
1.5
Shooting Angle (degrees)
0
Zero Range (yds)
200


Wind Speed (mph)
0
Wind Angle (degrees)
90
Altitude (ft)
0


Pressure (hg)
29.53
Temperature (F)
59
Humidity (%)
0.78


Ballistics Results - .45-70 405 grain




RANGE(YARDS)
VELOCITY(FPS)
ENERGY(FT.-LB.)
TRAJECTORY(IN)
COME UP IN MOA
COME UP IN MILS
WIND DRIFT(IN)
WIND DRIFT IN MOA
WIND DRIFT IN MILS


Muzzle
1200
1295
-1.5
0
0
0
0
0


25
1154
1197
5.3
-20
-5.8
0
0
0


50
1113
1114
10.4
-19.7
-5.7
0
0
0


75
1078
1044
13.7
-17.4
-5.1
0
0
0


100
1046
984
15.1
-14.4
-4.2
0
0
0


125
1019
933
14.6
-11.2
-3.2
0
0
0


150
994
888
12
-7.6
-2.2
0
0
0


175
971
848
7.2
-3.9
-1.1
0
0
0


200
951
812
0.1
0
0
0
0
0


225
931
780
-9.5
4
1.2
0
0
0


250
913
750
-21.5
8.2
2.4





1500 fps


http://www.hornady.com/assets/snippets/custom/ballistics_calculator/images/print-header.jpg


Your Input Variables



Ballistic Coefficient
0.214
Velocity (ft/s)
1500
Weight (grains)
405


Maximum Range (yds)
250
Interval (yds)
25
Drag Function
G1


Sight Height (inches)
1.5
Shooting Angle (degrees)
0
Zero Range (yds)
200


Wind Speed (mph)
0
Wind Angle (degrees)
90
Altitude (ft)
0


Pressure (hg)
29.53
Temperature (F)
59
Humidity (%)
0.78


Ballistics Results - 45-70 405



RANGE(YARDS)
VELOCITY(FPS)
ENERGY(FT.-LB.)
TRAJECTORY(IN)
COME UP IN MOA
COME UP IN MILS
WIND DRIFT(IN)
WIND DRIFT IN MOA
WIND DRIFT IN MILS


Muzzle
1500
2023
-1.5
0
0
0
0
0


25
1430
1839
3.2
-12.3
-3.6
0
0
0


50
1365
1675
6.9
-13.1
-3.8
0
0
0


75
1304
1528
9.3
-11.8
-3.4
0
0
0


100
1247
1399
10.5
-10
-2.9
0
0
0


125
1196
1287
10.3
-7.9
-2.3
0
0
0


150
1151
1190
8.6
-5.4
-1.6
0
0
0


175
1110
1109
5.2
-2.8
-0.8
0
0
0


200
1075
1040
0.1
0
0
0
0
0


225
1044
981
-7
3
0.9
0
0
0


250
1017
930
-16
6.1
1.8
0
0
0






So at 100 yard range aiming at center at

1200 fps you need to be hitting 15" high to be on at 200 ish

1500 fps you need to be 10 1/2" high to be on at 200 ish

[Walstr]

Sagebrush7;
What rifle & Pb alloy are you having such good luck with? Marlin 1895 perhaps? No leading issues @ 50gr of IMR3031? Whew!!
Wally

[tsubaki]

Do I understand then a 21" Holdover @ 100yds, 1500fps, will put me on target @ 200yds?

No, 21" is the difference in drop between the 100 and 200 yard target.
Do like Artful said and hold over 10" at 100 yards to hit center at 200 yards. Or hold over 21" on the 200 yard target to accomplish the same thing.

[tsubaki]

On most of my firearms I generally try to keep the bullet rise (line of sight) somewhere around 1 1/2" at any given range.
The 1500fps chart I posted very nicely accomplishes this.
If you put a little thought process into it, you will get even more confused.
I would zero at 100 yards and place a target at 25/50/75 yards and see how high or low it may shoot. Just so you will know.

I'm intending to cast some 405gr boolits and throwing them at the same velocities you are playing with, even the same power too. But for now I have lots of 300gr j-words to go through.
So please do keep us up to date on your findings.

[Sagebrush7]

Hey Wally
We have two Marlin 45/70 1895 SS in the family. Back when we were looking for speed the testing was done with full cases of IMR 3031. Older now to keep my teeth and brain function we don't do that. Water dropped wheel weights with 2% tin did not lead the micro groove barrels. I would always end the shooting session with a couple of Lee 500 gr gas checked bullets to clean things up and rearrange the hair. I don't have any hair now to arrange. The Lee 340 grain Gould bullet is outstanding in the Marlins. Accurate and least punishing! No gas check to install, just use a good lube. All the other non gas check bullets I used milk carton wads pushed into the case with the bullet. It is best not to leave an extra airspace between bullet wad and powder. IMR3031 will give you a full case with the larger bullets and compressed loads.


Sagebrush7;
What rifle & Pb alloy are you having such good luck with? Marlin 1895 perhaps? No leading issues @ 50gr of IMR3031? Whew!!
Wally