Author Topic: Need some ballistic info  (Read 736 times)

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Offline Varmint Hunter

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Need some ballistic info
« on: October 04, 2007, 12:06:50 PM »
I'll be heading out soon for a southern muzzleloader whitetail hunt. The land owner said to expect shot opportunities from 100yds to 200yds.

I am shooting the new 270gr Platinum Powerbelts w/ aerotips at 1,525 ft/sec. I sighted the rifle in so that it is 3" high @ 100yds. Where will impacts be @ 200yds?

Offline quickdtoo

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Re: Need some ballistic info
« Reply #1 on: October 04, 2007, 12:15:37 PM »
Powerbelt data is available on their website, but they show higher muzzle velocities.

Tim

http://www.powerbeltbullets.com/docs/PBB26inchballistics.pdf
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Offline quickdtoo

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Re: Need some ballistic info
« Reply #2 on: October 04, 2007, 12:22:02 PM »
Here's calculated data using PB's BC of .220 and your velocity...

Trajectory for Custom .50 Cal 270gr Platinum PowerBelt at 1525 Feet per Second
At an Elevation Angle of: 0 degrees
Ballistic Coefficients of: 0.22   0.22   0.22   0.22   0.22
Velocity Boundaries (Feet per Second) of: 1525   1525   1525   1525
Wind Direction is: 0.0 o'clock and a Wind Velocity of: 0.0 Miles per hour
Wind Components are (Miles per Hour): DownRange: 0.0   Cross Range: 0.0   Vertical: 0.0
Altitude: 0 Feet with a Standard Atmospheric Model.
Temperature: 59 F
Data Printed in English Units
Range   Velocity   Energy   Momentum   Drop   Bullet Path   Wind Drift   Time of Flight
(Yards)   (Ft/Sec)   (Ft/Lbs)   (Lb-Sec)   (inches)   (inches)   (inches)   (Seconds)
0   1525.0   1394.0   1.83   0.0   -1.5   0.0   0.000000000
25   1456.2   1271.1   1.75   -0.48   1.26   0.0   0.050333964
50   1391.1   1160.0   1.67   -1.99   3.0   0.0   0.103035511
75   1330.0   1060.4   1.59   -4.62   3.62   0.0   0.158182512
100   1273.3   971.8   1.53   -8.47   3.01   0.0   0.215827950
125   1221.3   894.0   1.46   -13.67   1.05   0.0   0.275988533
150   1174.3   826.6   1.41   -20.33   -2.36   0.0   0.338636041
175   1132.5   768.8   1.36   -28.55   -7.34   0.0   0.403694091
200   1095.8   719.7   1.31   -38.48   -14.02   0.0   0.471046049
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Offline Varmint Hunter

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Re: Need some ballistic info
« Reply #3 on: October 04, 2007, 01:49:48 PM »
WOW - 14" of drop! A guy at the range told me to expect impact to be 2"-3" below POA but I wasn't too sure about that.

Thanks for your help.

Offline Semisane

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Re: Need some ballistic info
« Reply #4 on: October 04, 2007, 01:58:00 PM »
If you know the bullet weight, ballistic coefficient, and muzzle velocity, you can get a pretty good idea of trajectory using this free calculator.

http://www.handloads.com/calc/

Set the "intervals" for 25 yards and plug in different distances in the "sight in at" box and you can find your best trajectory for 200 yards.

It's pretty close to published data I've compared it to.
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Offline quickdtoo

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Re: Need some ballistic info
« Reply #5 on: October 04, 2007, 01:58:28 PM »
The best way to find out what the drop actually is, is to shoot it at that range to confirm it if you can. ;) But if you can increase your velocity, it would help a lot.

Tim

"Always do right, this will gratify some and astonish the rest" -  Mark Twain

Offline Varmint Hunter

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Re: Need some ballistic info
« Reply #6 on: October 05, 2007, 03:24:41 PM »
I recently switched from 100gr of 777 powder (loose) to 2-50gr pellets of 777. I also switched from a standard 209 primer to a Rem CleanBore 209 primer. This switch resulted in a whopping 200 ft/sec loss in velocity. Somehow I've got to get the velocity back in order to flatten the trajectory.

Offline poncaguy

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Re: Need some ballistic info
« Reply #7 on: October 05, 2007, 03:59:49 PM »
At the range ur shooting, I would use 3 777 pellets or 120 grains of loose powder and a 250 grain Shockwave........

Offline Redhawk1

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Re: Need some ballistic info
« Reply #8 on: October 06, 2007, 12:11:23 AM »
Varmint Hunter if you really want to be able to shoot too 200 yards do what I did with my Encore.
I am loading 120 gr. of loose triple7 or you can use 3 pellets of triple7, a Remington Kleenbore 209 primer and a 250 gr. T/C bonded shock wave bullet.
The key to this all is the Nikon Omega 250 BDC scope. I have my Encore sighted in for 100 yards dead on. I use the 4 circles in the scope to compensate for bullet drop. Like I said the cross hairs are dead on at 100, the first circle is 150 yards the second circle is 200 yards the third is 225 yards and the bottom circle is 250 yards.
I have shot at all but the 250 yard range and the impact was dead on for all the listed distances. I would not hesitate to make a 250 yard shot with this set up.
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Offline Varmint Hunter

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Re: Need some ballistic info
« Reply #9 on: October 08, 2007, 08:06:48 AM »
Redhawk,

I've heard from many muzzloaders that they saw a measurable loss in accuracy when moving up in powder charge from 2 pellets of 777 to 3 pellets. How are your groups @ 200yds using 120gr loose  or 3 pellets?

Have you tried 300gr sabots with the same charge?

Offline Redhawk1

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Re: Need some ballistic info
« Reply #10 on: October 08, 2007, 08:54:23 AM »
My load as I described above works very good out to 200 yards. I get 3 inch groups. But you heard right about people getting worse groups when moving up in powder weight. But if they took the time, they can find a bullet that will give them good performance with more powder or pellets as I have. The only way to really find out, is to go to the range and do it. Just remember, what works for me, might not work as well for you. It is all trial and error.

I have not tried the 300 gr. sabots, because the scope is set up for the 250 gr. weight bullets.
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Offline Varmint Hunter

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Re: Need some ballistic info
« Reply #11 on: October 08, 2007, 09:38:01 AM »
Gottcha - Thanks for the info.

Offline dmurphy317

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Re: Need some ballistic info
« Reply #12 on: October 09, 2007, 06:52:38 AM »
Another way to set your rifle up is to do whats called a max point blank range sight in. For my son's Apex, which is a similar design to the Omega, I use 130gr of Pyro pellets and a 250 Shockwave. MV is right at 2100fps and a 6" PBR setup puts it 3" high at 100 yards and 3" low at 200 yards. At 250 yards its down about 11" so you just need to put the crosshair on the back or slightly above it for that shot, just need to know the distance. This is based on the 7500 foot elevation we typically hunt at. At sea level it drops about 2" more at 250. I have shot groups of 2.5 to 3 " at 200 yards with this load. It should be able to be duplicated with around 110 to 115gr of 777 loose if desired. Good luck with it.
David

It's better to shoot for the sky and come a bit short than to shoot for the ground and hit every time. After all, the ground is just a place to start, the sky's the limit.