Well I have spent a lot of time on this and it has literally taken years to dial this gun in. I am shooting 98 grains of Retumbo with velocities between 3030 and 3050 so I had leuplod build the turret for the 250 NPT. at 3040fps. It shoots just over an inch at 200 and at 500 about an 9 inch group. However with the nosler dial at 500 I am 12 inches low so I have to come up 3/4 of a minute to be zero ie in the bull at 500. So is the difference between theoretical and actual performance or BC is not quite rite or what, temp and alt are right on? Has anyone else experienced this? I have figured the dope out and shoot it well just looking to do better. This guy did not know I had to come up 2 clicks.
leupold CDS and the 338 RUM 250 npt.
- Thread starter fwood
- Start date
Might look at the height of the scope above the bore and make sure that measurement is accurate. If you post all the specifics of your atmospheric conditions and sight height I can run some numbers for you. Also share what your actual drop at 500 is in MOA.
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- Nov 4, 2004
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Congratulations on a nice bull. The 338 RUM loaded with the 250 gr PT is a hammer.
I load 98.6 grs of Retumbo with the 250 gr PT for a MV of 3014 fps and .5 MOA accuracy in my M700 LSS.
Not sure why the CDS dial is off but it may be due to elevation and temp variances.
JD338
I load 98.6 grs of Retumbo with the 250 gr PT for a MV of 3014 fps and .5 MOA accuracy in my M700 LSS.
Not sure why the CDS dial is off but it may be due to elevation and temp variances.
JD338
Guy Miner
Master Loader
- Apr 6, 2006
- 17,525
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Elevation can be a pretty big factor at longish ranges.
Am sure there are some other explanations as well. Just confirming JD's assertion.
And yes, CONGRATS on the bull!
Guy
Am sure there are some other explanations as well. Just confirming JD's assertion.
And yes, CONGRATS on the bull!
Guy
- Thread starter
- #5
Your Input Variables
Ballistic Coefficient 0.473 Velocity (ft/s) 2990 Weight (grains) 250
Maximum Range (yds) 1000 Interval (yds) 100 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) 7500
Pressure (hg) 29.53 Temperature (F) 32 Humidity (%) 0.2
This seems to more closely duplicate the way the gun is shooting. The only variable that changed here is the velocity was moved from 3050 on my turret (thought it was 3040) to 2990 which is showing a 6.9 moa come up at 500 yards so I need to go back to the range and re-chronograph the loads. It might have been a bit warmer than I anticipated at the range last time. If you guys want to run the data and see what you come up with two sets of eyes are always better.
Yep JD the 338 rum is about as big a hammer in the woods as there is. I have only shot two animals with it, an Alaskan Moose and a Colorado Elk. The moose ran 25 feet and expired the NPT penetrated 3+ feet on the quartering shot, got a lung and the heart. The Elk was 364 on the range finder, I hit the heart, lucky shot, and he just locked up and fell over. I have tried a few bullets and the Partition seems to shoot the best.
Thank
Fwood
Ballistic Coefficient 0.473 Velocity (ft/s) 2990 Weight (grains) 250
Maximum Range (yds) 1000 Interval (yds) 100 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) 7500
Pressure (hg) 29.53 Temperature (F) 32 Humidity (%) 0.2
This seems to more closely duplicate the way the gun is shooting. The only variable that changed here is the velocity was moved from 3050 on my turret (thought it was 3040) to 2990 which is showing a 6.9 moa come up at 500 yards so I need to go back to the range and re-chronograph the loads. It might have been a bit warmer than I anticipated at the range last time. If you guys want to run the data and see what you come up with two sets of eyes are always better.
Yep JD the 338 rum is about as big a hammer in the woods as there is. I have only shot two animals with it, an Alaskan Moose and a Colorado Elk. The moose ran 25 feet and expired the NPT penetrated 3+ feet on the quartering shot, got a lung and the heart. The Elk was 364 on the range finder, I hit the heart, lucky shot, and he just locked up and fell over. I have tried a few bullets and the Partition seems to shoot the best.
Thank
Fwood
- Thread starter
- #6
Your Input Variables
Ballistic Coefficient 0.473 Velocity (ft/s) 2990 Weight (grains) 250
Maximum Range (yds) 1000 Interval (yds) 100 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) 7500
Pressure (hg) 29.53 Temperature (F) 32 Humidity (%) 0.2
Ballistics Results - NPT
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 2990 4963 -1.5 0 0 0 0 0
100 2829 4443 1.4 -1.4 -0.4 0 0 0
200 2674 3970 0 0 0 0 0 0
300 2525 3538 -6.3 2 0.6 0 0 0
400 2380 3144 -18 4.3 1.3 0 0 0
500 2240 2785 -36 6.9 2 0 0 0
600 2104 2458 -60.8 9.7 2.8 0 0 0
700 1974 2163 -93.5 12.8 3.7 0 0 0
800 1848 1896 -135.1 16.1 4.7 0 0 0
900 1728 1658 -187 19.8 5.8 0 0 0
1000 1615 1447 -250.5 23.9 7 0 0
This seems to more closely duplicate the way the gun is shooting. The only variable that changed here is the velocity was moved from 3050 on my turret (thought it was 3040) to 2990 which is showing a 6.9 moa come up at 500 yards so I need to go back to the range and re-chronograph the loads. It might have been a bit warmer than I anticipated at the range last time. If you guys want to run the data and see what you come up with two sets of eyes are always better.
Yep JD the 338 rum is about as big a hammer in the woods as there is. I have only shot two animals with it, an Alaskan Moose and a Colorado Elk. The moose ran 25 feet and expired the NPT penetrated 3+ feet on the quartering shot, got a lung and the heart. The Elk was 364 on the range finder, I hit the heart, lucky shot, and he just locked up and fell over. I have tried a few bullets and the Partition seems to shoot the best.
Thank
Fwood
Ballistic Coefficient 0.473 Velocity (ft/s) 2990 Weight (grains) 250
Maximum Range (yds) 1000 Interval (yds) 100 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) 7500
Pressure (hg) 29.53 Temperature (F) 32 Humidity (%) 0.2
Ballistics Results - NPT
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 2990 4963 -1.5 0 0 0 0 0
100 2829 4443 1.4 -1.4 -0.4 0 0 0
200 2674 3970 0 0 0 0 0 0
300 2525 3538 -6.3 2 0.6 0 0 0
400 2380 3144 -18 4.3 1.3 0 0 0
500 2240 2785 -36 6.9 2 0 0 0
600 2104 2458 -60.8 9.7 2.8 0 0 0
700 1974 2163 -93.5 12.8 3.7 0 0 0
800 1848 1896 -135.1 16.1 4.7 0 0 0
900 1728 1658 -187 19.8 5.8 0 0 0
1000 1615 1447 -250.5 23.9 7 0 0
This seems to more closely duplicate the way the gun is shooting. The only variable that changed here is the velocity was moved from 3050 on my turret (thought it was 3040) to 2990 which is showing a 6.9 moa come up at 500 yards so I need to go back to the range and re-chronograph the loads. It might have been a bit warmer than I anticipated at the range last time. If you guys want to run the data and see what you come up with two sets of eyes are always better.
Yep JD the 338 rum is about as big a hammer in the woods as there is. I have only shot two animals with it, an Alaskan Moose and a Colorado Elk. The moose ran 25 feet and expired the NPT penetrated 3+ feet on the quartering shot, got a lung and the heart. The Elk was 364 on the range finder, I hit the heart, lucky shot, and he just locked up and fell over. I have tried a few bullets and the Partition seems to shoot the best.
Thank
Fwood
Guy Miner
Master Loader
- Apr 6, 2006
- 17,525
- 4,786
Excellent results! 
Rem Jim
Handloader
- Jan 7, 2012
- 676
- 2
Nice Elk - i have being using H1000 in my Rum but now just gotten hold of 5 Lbs of Remtumbo - I am going to give it a try with your 98 gr Load and some 250 gr NPT Bullets and see what the results are ! RJ
Yup my guess is your velocity is slightly off from the turret. I did a reverse calculation of your muzzle velocity based on the info given and came up with 2972.8fps. Keeping in mind that the closer the distance the less accurate the calculation. If you have verified drop data past 500 yards let me know.
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- Oct 30, 2004
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did you shoot the gun at 500 yards with that load prior to making up the dials?
- Thread starter
- #11
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