Ballistic Question?

[Panhandle]

A couple days ago with my Triumph I shot 110gns BH with some 250 and 300 gn XTP's with exceptional results. Both bullets grouped under an inch at 100yds. Last night I punched all the data into a ballistics calculator to get a idea of what to expect velocity, trajectory, and energy wise. When doing so I changed the BC numbers to match the Hornady SST and re-calculated. I was surprised with the results. Are these figures correct? It's hard to believe that there is this much difference between the two in velocity and energy at 200 yds.According to these tables the SST at 200yds is doing the same as the XTP at around 100yds. If that is correct those are significant numbers.
Zen

250 gn XTP / Listed BC .153

Range Velocity Impact Energy
0 2010 -1.5 2243
50 1760 2.46 1720
100 1541 3.59 1318
150 1350 1.22 1012
200 1196 -6.3 794


250gn SST / Listed BC .287

Range Velocity Impact Energy
0 2010 -1.5 2243
50 1875 1.87 1952
100 1750 2.75 1700
150 1632 0.77 1479
200 1520 -4.48 1283

 

[Mark whiz]

I've always found that the ballistic calculators don't work really well with muzzleloading - close but no cigar. Did your calculator actually have BH powder in it's program? If you approximated it, then your results can only be an approximation.

BUT, since the SST has twice the BC of the XTP, you do have to expect it to carry more speed and power downrange - it's just a matter of how much.

 

[Lee 9]

With a 25 % difference the BC you will find a very noticeable difference the drop, the energy, and the wind drift. The 200 gr 40 caliber bullets especially the Shock Wave and I believe you will see two maybe 3 more 40 caliber high BC bullets on the market in the next year. I hear one of them will be an all copper.
If you are really interested in a long range bullet run the 200 gr SW with a BC of .269 at 2200 fps [120 gr BH through your calculator.

 

[Busta]

Panhandle,

I am not positive, but I would say your BC figure for the 250 SST is way to high. I would think it shoud be right about the same as the 250 FTX which is .210. The .430" 265 gr FTX BC is only .225, and conventional wisdom would tell us that the .452" 250 SST which is shorter, fatter, and lighter would have a lower BC. I think the SST BC's were always inflated.

Try it in your calculator with a BC around .210 or .220 and see what you get. I think those numbers will be a lot closer to real world results.

http://www.hornady.com/story.php?s=789

 

[Panhandle]

I think you all are right about the BC. I got the number from the BC calulator on the program. It was very generic. Diameter bullet / weight of bullet / HP or Spitzer etc. Thanks
Zen

 

[squirrelhawker]

yes...too good to be true. The BC for the 250 SST is .210.

 

[squirrelhawker]

Ballistics Calculation

Input Variables Firearm type Rifle Sight Height 1.5
Bullet Weight (grains) 250 Ballistic Coefficient .210
Muzzle Velocity (fps) 2010 Temperature 75
Barometric Pressure (hg) 29.53 Relative Humidity 78%
Zero Range (yards) 100 Wind Speed (mph) 0



Ballistics Table in Yards 250 SST 250 gr., .210 B.C. www.hornady.com

Range (yards) Muzzle 50 100 200 300 400 500
Velocity (fps) 2010 1838 1676 1390 1171 1032 942
Energy (ft.-lb.) 2243 1875 1559 1073 762 591 492
Trajectory (100 yd. zero) -1.5 0.5 0.0 -11.0 -40.2 -94.7 -180.3
Come Up in MOA -1.5 -1.0 0.0 5.3 12.8 22.6 34.4




The following table is provided as a "cheat sheet" that you can tape to your gun.
Ballistics Table in Yards 250 SST 250 gr., .210 B.C. www.hornady.com

Range (yards) Muzzle 50 100 200 300 400 500
Trajectory (100 yd. zero) -1.5 0.5 0.0 -11.0 -40.2 -94.7 -180.3
Come Up in MOA -1.5 -1.0 0.0 5.3 12.8 22.6 34.4



Ballistics Calculation

Input Variables Firearm type Rifle Sight Height 1.5
Bullet Weight (grains) 250 Ballistic Coefficient .146
Muzzle Velocity (fps) 2010 Temperature 75
Barometric Pressure (hg) 29.53 Relative Humidity 78%
Zero Range (yards) 100 Wind Speed (mph) 0



Ballistics Table in Yards 250 XTP 250 gr., .146 B.C. www.hornady.com

Range (yards) Muzzle 50 100 200 300 400 500
Velocity (fps) 2010 1765 1544 1194 1000 890 809
Energy (ft.-lb.) 2243 1730 1323 791 555 439 363
Trajectory (100 yd. zero) -1.5 0.7 0.0 -13.4 -51.2 -121.6 -231.6
Come Up in MOA -1.5 -1.2 0.0 6.4 16.3 29.0 44.2




The following table is provided as a "cheat sheet" that you can tape to your gun.
Ballistics Table in Yards 250 XTP 250 gr., .146 B.C. www.hornady.com

Range (yards) Muzzle 50 100 200 300 400 500
Trajectory (100 yd. zero) -1.5 0.7 0.0 -13.4 -51.2 -121.6 -231.6
Come Up in MOA -1.5 -1.2 0.0 6.4 16.3 29.0 44.2

 

[vabowhntr]

The wind drift might be the most significant of all, about 6 inches different (~10" vs ~16") in a 10 mph crosswind. In a no wind scenario, you are only about 3" different at 200 yards if both are sighted in at 100, and both will kill deer at that range.

Of course, if I wanted to shoot that far I would go with the 200 gr SW. Should be 2" less wind drift and drop than the 250, with about the same energy.

 

[squirrelhawker]

The wind drift might be the most significant of all, about 6 inches different (~10" vs ~16") in a 10 mph crosswind. In a no wind scenario, you are only about 3" different at 200 yards if both are sighted in at 100, and both will kill deer at that range.

Of course, if I wanted to shoot that far I would go with the 200 gr SW. Should be 2" less wind drift and drop than the 250, with about the same energy.

Tell me about the 200 sw. Actual bullet diameter? Im speaking of use in a 50 cal.

 

[squirrelhawker]

I see there is a topic already on the 200sw. We can carry on there. :wink: