Joined: Apr 18, 2007 Posts: 66 Location: Ft. Hood, TX
Posted: Mon Aug 13, 2007 8:43 pm Post subject: Bullet drop question.
I was out at the range recently on Ft Hood, TX shooting my Tikka 30-06sprg and have a question for yall. Because the range was military/civilian it's metric so my question will be in meters.
I don't have a chrony so I don't know exactly how fast my loads are goin but I estimate about 2600fps. I started zeroed at 50m dead center. Then I moved out to 100m (approx 110yds) and shot without adjustment. I'm shooting a Nosler BTBT .30cal 165grn with 54.5grn H4350. My drop at 100m with a 50m zero was about 1 1/4". It was a very hot humid day with zero value wind. My load shot at worst 1/2" from center with two together and one flyer. I shot from sandbags for and aft. Does this sound right to yall? I couldn't believe there would be that much drop in a 30-06 over 50m.
I brought my scope 6 clicks up and it's dead on at 100m now. At least under those atmospheric conditions.
_________________ Tikka T3 Light Stainiless Left-Hand 30-06 Springfield
Posted: Tue Aug 14, 2007 5:43 am Post subject: Re: Bullet drop question.
At that speed with that combo....
Assuming the wind was zero and the ambient temp 90ish F......
And assuming the altitude was 1000ish ASL.....
50 meter zero should yeild approximately .17 inches low at 100 meters, and 2.16 inches low at 150 meters.
On aside....2600 is way low for a 30 cal 165 grain anything, 'specially a Ballistic Tip. I don't have any load books handy at the moment so I can't relate a published Hodgdon MV to the grain weight charge you posted.
Am thinkin' though you could use a little more powder and bump that speed up, which in turn will flatten things out, and possibly get rid of those flyers.
I'm running 168 Match's and X's at 2900, give or take, which ain't no barn burner either, but......
If you could get that velocity, you would be .15 high at 100m and only 1.14 low at 150m.....
I generally as a rule sight in for zero at 250 yards with all of my bottleneck CF rifles and can hold dead on out to that mark....out past that it's quick twistin' turrets via MOA to compensate.
A Chrony is always handy and lessens the guessin' game a wee bit.................
Joined: Aug 22, 2005 Posts: 1032 Location: Phoenix, Arizona
Posted: Tue Aug 14, 2007 8:46 pm Post subject: Re: Bullet drop question.
Nosler lists 55.5gr of H4350 w/ the BTBT in an '06 @ 2757fps. 53.5 gr gives 2642fps. These velocities are out of a 24" barrel, however, the Tikka has a 22", so 2,650 fps or so seems about the right velocity in theory.
If we use the 2,600 fps figure and a 100yd zero, the trajectory would be
-4.5" @ 200yds, -15.9" @ 300yds.
Changing to a 200yd zero yields +2.2" @ 100yds, and -9.2 @ 200yds.
Knowing what your rifle actually does is far more important than text published ballistics. But, 2,600 fps MV is adequate for anything you ever find in Texas, IMO. That said, 2,900fps to 3,000 fps are max text loads and are normally achieved with slower powders than H4350.
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