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Post by Deleted on Aug 3, 2009 19:24:20 GMT -5
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 200-225 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 Drop ToF Energy Drift
0 2010 -1.5 0 0 2243 0
25 1878 0.79 0.36 0.04 1958 0
50 1760 2.46 1.34 0.08 1720 0
75 1648 3.44 3.01 0.13 1508 0
100 1541 3.59 5.5 0.17 1318 0
125 1442 2.84 8.9 0.22 1154 0
150 1350 1.05 13.34 0.28 1012 0
175 1268 -1.95 18.99 0.34 893 0
200 1196 -6.3 25.99 0.4 794 0
225 1134 -12.17 34.51 0.46 714 0
250 1083 -19.74 44.72 0.53 651 0
250gn SST / Listed BC .287
Range Velocity Impact Drop ToF Energy Drift
0 2010 -1.5 0 0 2243 0
25 1939 0.47 0.35 0.04 2087 0
50 1875 1.87 1.28 0.08 1952 0
75 1811 2.63 2.84 0.12 1821 0
100 1750 2.75 5.05 0.16 1700 0
125 1690 2.14 7.98 0.21 1586 0
150 1632 0.77 11.67 0.25 1479 0
175 1575 -1.41 16.18 0.3 1377 0
200 1520 -4.48 21.57 0.35 1283 0
225 1467 -8.49 27.9 0.4 1195 0
250 1417 -13.5 35.24 0.45 1115 0
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Post by sabotloader on Aug 4, 2009 1:02:58 GMT -5
Panhandle
Think might way high on your BC number for the 250 SST/SW...
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Post by Dave W on Aug 4, 2009 2:25:59 GMT -5
PanhandleThink might way high on your BC number for the 250 SST/SW... Ditto Try .241 for the 250 SST, works out pretty well for drops at 2600fps in the Savage. |
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Post by Deleted on Aug 4, 2009 6:19:16 GMT -5
That could very well be. I used the calculator that's with the program.
Zen
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Post by sabotloader on Aug 4, 2009 11:01:03 GMT -5
Panhandle
From what I can find - Hornady site - BC is 210 on the SST
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Post by rossman40 on Aug 4, 2009 12:56:48 GMT -5
My rule is never to trust a factory BC unless the give you velocity data to go with it. The BC you use is one thing but you have to use a drag factor (G1) that is over 100 years old and doesn't quite work with modern bullets. Lapua has started using radar data to show the BC over the spectrum and even has a program that uses the data to get dead nuts accurate.  Companies are quick to use the highest number they can to sell their bullets. With the XTP your talking about a pistol bullet whose BC was probly calculated at pistol MVs and now your pushing it 50% faster. I basicly use computer calculated data as a guestimate and verify my drop table on the range. Guys will sometimes take real world drop data and use that to backwards figure out the BC to fill in the gaps and longer ranges. You usually end up getting burned because the data is only good over a segment of the range spectrum. Of course with a ML we are talking about a shorter spectrum then say a out to 1000yd shooter. If you fudge your BC to match the drop your velocities at range are junk (maybe just not real accurate) too. |
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Post by wilmsmeyer on Aug 4, 2009 16:24:47 GMT -5
Kinda like the dark side of the moon.........get it?
Anyway, in general terms from shooting 250 TMZ's, SST's and XTP's, there is not enough "real world" differences out to 200 yds...trajectory wise...to miss a deer.
To Rossman's point, everyone should shoot at the ranges they intend to ethically kill game. Make your own drop chart and stick it on your stock. After you do this, the numbers don't matter much.
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Post by davewolf on Aug 4, 2009 21:10:52 GMT -5
Great subject matter, like it and appreciate it!
Have a great day!
Dave
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Post by reloader on Aug 5, 2009 10:22:39 GMT -5
Zen,
Did you clock those loads?
I clocked some 250SSTs in HPH12 and some 250TMZ in the blue EZ sabots a few weeks back, both over 110grn of BH209 in an Omega 28" bbl. The 250 SSTs avg 2150 fps and the TMZ avg 2115fps.
Hope that helps alittle.
have a good one,
Reloader
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Deleted
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Post by Deleted on Aug 5, 2009 10:37:11 GMT -5
Zen, Did you clock those loads? I clocked some 250SSTs in HPH12 and some 250TMZ in the blue EZ sabots a few weeks back, both over 110grn of BH209 in an Omega 28" bbl. The 250 SSTs avg 2150 fps and the TMZ avg 2115fps. Hope that helps alittle. have a good one, Reloader Reloader... Yes, I did chrono those loads. 2010fps Avg with 250gn XTP and 1940pfs Avg with 300XTP. Last winter those velocities were about 50fps lower at 30 degrees. I measured the powder with a TC see thru plastic measure. I think it throws the charges a little light. I'm going to go with the 300gn XTP's this year....they sure shoot good. The same goes for the .458 Remington HP. Thanks for the info guys...... Zen |
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Post by grouse on Aug 6, 2009 21:36:12 GMT -5
The 250SST might fly a little better then the XTP. But, the XTP is alot better on Deer size game then the SST.  |
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