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Joined: Jun 2012
Posts: 33
Campfire Greenhorn
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OP
Campfire Greenhorn
Joined: Jun 2012
Posts: 33 |
I didn't have my chronograph with me today, and I wanted to test out a new load in my Tikka 7-08. I checked my zero at 200 yards, and everything was good. I went back to 350, and ended up dialing + 4.75 moa to get zerod. in order for this to match up in my ballistic calculator, I need to enter a velocity of 2575 fps, which seams about 225 fps flow for 42 grains of varget and a 140 grain Nosler ballistic tip. Every manual, and everyone online seams to be getting around 2800-2850 with this load. Is my rifle really this slow, or is there another factor I may be overlooking?
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Joined: Oct 2011
Posts: 2,926
Campfire Regular
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Campfire Regular
Joined: Oct 2011
Posts: 2,926 |
Your scope isn't moving the indicated amount per click.
The BC you are using for your bullet is wrong.
I have no idea if either of these statements are correct, but they are other possible causes of what you are seeing.
David
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Joined: Jan 2011
Posts: 590
Campfire Regular
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Campfire Regular
Joined: Jan 2011
Posts: 590 |
Probably the scope. Folks would riot if they knew what percentage of scopes didn't track correctly. I borrowed a 35 Whelen yesterday to use for a "primitive weapon" draw hunt. Zeiss Divari wouldn't track for [bleep].
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Joined: Aug 2005
Posts: 15,648 Likes: 1
Campfire Ranger
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Campfire Ranger
Joined: Aug 2005
Posts: 15,648 Likes: 1 |
I'd chronograph - Tons of things can cause that -
- Greg
Success is found at the intersection of planning, hard work, and stubbornness.
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Joined: Oct 2009
Posts: 2,934
Campfire Regular
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Campfire Regular
Joined: Oct 2009
Posts: 2,934 |
My bet is on the scope. I have a Zeiss conquest that tracks close to 1/6" which means a lot more MOA is needed to dial given ranges.
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Joined: May 2015
Posts: 708
Campfire Regular
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Campfire Regular
Joined: May 2015
Posts: 708 |
It's not like Nosler to inflate the G1 BC of their bullets Also, a Tall Test will reveal what the actual 'clicks' per MOA is, factor this into your calculation.
Last edited by Axtell; 10/30/16.
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Joined: Nov 2003
Posts: 28,875 Likes: 1
Campfire Ranger
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Campfire Ranger
Joined: Nov 2003
Posts: 28,875 Likes: 1 |
My bet is on the scope. I have a Zeiss conquest that tracks close to 1/6" which means a lot more MOA is needed to dial given ranges. Would you clarify this please?
"Only Christ is the fullness of God's revelation." Everyday Hunter
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Joined: Jun 2004
Posts: 44,882 Likes: 10
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2004
Posts: 44,882 Likes: 10 |
I'm reading that as more indicated MOA is required.
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Joined: Jan 2007
Posts: 35,900
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2007
Posts: 35,900 |
Until you chronograph you are just guessing.
I would not drop dead from shock to see a rifle fail to deliver as shown in a loading manual. It sure would not be the first time.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Oct 2009
Posts: 2,934
Campfire Regular
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Campfire Regular
Joined: Oct 2009
Posts: 2,934 |
My bet is on the scope. I have a Zeiss conquest that tracks close to 1/6" which means a lot more MOA is needed to dial given ranges. Would you clarify this please? Meaning each click equals ca. 1/6" at 100yds rather than the listed 1/4" @100yds. I have owned this scope for several years and it has been this way since day one. I have verified this out to 800 yds. It is on my main calling rifle and gets lots of use.
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Joined: Dec 2002
Posts: 6,930
Campfire Tracker
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Campfire Tracker
Joined: Dec 2002
Posts: 6,930 |
Without a chronograph, all you have is a bad guess.
Selmer "Daddy, can you sometime maybe please go shoot a water buffalo so we can have that for supper? Please? And can I come along? Does it taste like deer?" - my 3-year old daughter
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Joined: Dec 2002
Posts: 6,930
Campfire Tracker
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Campfire Tracker
Joined: Dec 2002
Posts: 6,930 |
Without a chronograph, all you have is a bad guess.
Selmer "Daddy, can you sometime maybe please go shoot a water buffalo so we can have that for supper? Please? And can I come along? Does it taste like deer?" - my 3-year old daughter
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Joined: Jan 2010
Posts: 8,423
Campfire Outfitter
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Campfire Outfitter
Joined: Jan 2010
Posts: 8,423 |
Did you enter the correct twist and the correct BC for the twist in your rifle.
Example my 264 win has a crap factory twist of 9. The 140 gr, Berger BC has to be deflated from.307 to .295 G7. I believe off the top of my head.
That slower twist will make it appear that the rifle is slow to get the numbers to match your ballistics calculations.
Matching the bullet to the twist and actual BC with said twist will reveal the velocity clearer. The important part is to enter all values in the ballistic calculator exactly.
Last edited by fredIII; 11/01/16.
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