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Anyone own a 7mm 300 Win Mag?

 
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  #379  
Old 08-03-2013, 09:50 AM
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Re: Anyone own a 7mm 300 Win Mag?

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Originally Posted by 300stw View Post
all loads were shot in a 1.5 hour time frame this afternoon, chrony and shooting bench stayed in same exact spots, overcast the whole time, no acces to anothe chronograph,,,, ,
Then you are screwed... I have 3 chrony's I can say with confidence all 3 give different readings and all 3 are wrong.

Also I learned, especially with a Chrony, it needs to be at least 18' from the muzzle or the blast rattles the screens and give erratic readings.

Another thought is if you are confident you are only getting 2860 from 73 gr of H-1000 and a 180, I would check my scales.

I have built 3 of these rifles and all were shot with 180 Bergers. I started in the 72 ~73 gr charge with H-1000. In RWS brass, which will require a lesser charge weight due to the redued case volume, 73 gr was well over 3000 in a 29" tube at 4100' asl.

My advice is forget the Chrony, go work up an accurate load at 200 yards. Then take it out to 800 to 1000 yards and find the spot on drops. Ten let the ballistic program tell you the velocity.

Jeff
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  #380  
Old 08-03-2013, 01:26 PM
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Re: Anyone own a 7mm 300 Win Mag?

Jeff do you just use the chrony for ES ?
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  #381  
Old 08-03-2013, 03:00 PM
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Re: Anyone own a 7mm 300 Win Mag?

Shot mine today to check velocity. My chrono would give me inconsistent readings. Load is 74.5 h1000 with fed210m primers 180 vlds. Zero at 300 and 10.5 moa drop to 750. With the pressure bein about 30 and temp 80 I am getting around 3120. The load is hotter than i would like but not too bad. This is with Norma brass.

It also did a 3 shot two inch group at 500 yards this morning.
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  #382  
Old 08-03-2013, 07:14 PM
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Re: Anyone own a 7mm 300 Win Mag?

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Originally Posted by cummin_un_glued View Post
Jeff do you just use the chrony for ES ?
I do for initial development. But I wuld rather go by a tape measure on the vertical of a 1000 yd group or two.

Jeff
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  #383  
Old 08-03-2013, 08:33 PM
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Re: Anyone own a 7mm 300 Win Mag?

I kinda figured that you only used them for powder comparisons during initial development. that is my plan also.
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  #384  
Old 08-03-2013, 09:13 PM
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Re: Anyone own a 7mm 300 Win Mag?

I have a like new set of RCBS 3 die set for this cartridge plus a bag of 300W brass if anyone is interested. $170 shipped powdr
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  #385  
Old 08-04-2013, 11:14 AM
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Re: Anyone own a 7mm 300 Win Mag?

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Originally Posted by powdr View Post
I have a like new set of RCBS 3 die set for this cartridge plus a bag of 300W brass if anyone is interested. $170 shipped powdr

I'll take the dies, PM sent.
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