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300 rum standard deviation,HELP

 
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  #1  
Old 08-02-2010, 02:03 PM
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Location: north platte ne
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300 rum standard deviation,HELP

Hi everyone first time posting a thread,please bear with me .I have a rem sendaro 300 rum,my mv for my loads vairys mabey 45 fps from my fastist to my slowist.Iam using rem brass with 4 or 5 shots through them ,my gun loves 95 grs retumbo,with 210 vlds .5 moa mabey at 100 yards.I just annealed some brass and loaded some with different primers,havent shot them yet,is 45 fps to much deaviation. I wanna take this gun out to say a thousand yards ,but 45 fps difference seems like a lot ,that was for 5 shots ,anywhere from 3125 to 3170 or so ,does anybody have any ideas for me to try. Any help would be appreciated.
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  #2  
Old 08-02-2010, 02:53 PM
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Re: 300 rum standard deviation,HELP

I use federal 215 match primers in my .300 RUM and I shoot 210 bergers as well. I think the SD should be alot lower than that but I may be wrong I just shot my crony the other day so I can't say what my load is at this time but I have a nice group at 752 YARDS . My advice to you would be to start your load development @ 200 yards and once you have about an 1/2 inch group to 3/4 inch group ,move out to 300 and when it's nice in tight @ 300 go on out to 800-1000 yards Let the paper tell you what you need to know . my crony was the biggest lyer that i've ever seen . Not exactly what you was looking for but I atleast took a stab at it

Just my opinion.

Just noticed that this is your first post congrats and welcome to LRH someone thats a whole lot wiser than i will chime in hopefully......

BigBuck
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  #3  
Old 08-02-2010, 02:56 PM
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Re: 300 rum standard deviation,HELP

Running your load, 3125 from a 100yd zero gives 226.5" drop at 1000 yds, 3170 gives 219.1" drop at 1000 yds. So yeah you will need to get the extreme spread down to shoot out to 1000 yds.

Last edited by kiwi3006; 08-02-2010 at 04:58 PM.
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  #4  
Old 08-02-2010, 04:13 PM
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Location: Cranbrook, BC, Canada
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Re: 300 rum standard deviation,HELP

What are your groups like out at 300-400 yards. Shoot it and see what the vertical group size is. There are many things that can a do go wrong with chrony's all the time. 45fps is quite a bit of velocity change, especially if you are trying to go out to 1000. FWIW I load 95gr retumbo behind a 200gr partition with CCI primers in Nosler brass, this load holds under 0.3moa vertical.

Is there any reloading steps that could be giving you this variation? Are you using a good digital scale? Varying powder charges will contribute to velocity differences.

Shoot at 300 yards and try and get your loads to group under half MOA for vertical size. Try going up and down in .2gr increments, and you will find the sweet spot.
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Old 08-03-2010, 10:05 AM
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Re: 300 rum standard deviation,HELP

Welcome, glad to have you here. Lots of good folks and lots of good info. You mentioned .5 moa @ 100 yards...so at first glance one might think such wide spreads in MV are attributed to a faulty chrony, however IMHO I think you should take it out further where if you do have significant MV spreads it'll be more apparent...then again maybe at greater distances the .5 moa may hold up in which case you may have a faulty chronyor groups open up and bear out your chrony readings in which case it could be your loads or something else. Let us know how it goes at greater distances. Enjoy.
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  #6  
Old 08-03-2010, 10:20 AM
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Re: 300 rum standard deviation,HELP

Quote:
Originally Posted by bigbuck View Post
I just shot my crony the other day..............my crony was the biggest lyer that i've ever seen.
That's still no reason to shoot your chrony.

Seriously, sorry to hear you shot it...is it beyond repair or just need a new screen or something?
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  #7  
Old 08-03-2010, 10:33 AM
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Re: 300 rum standard deviation,HELP

Quote:
Originally Posted by Chas1 View Post
That's still no reason to shoot your chrony.

Seriously, sorry to hear you shot it...is it beyond repair or just need a new screen or something?
I posted pics of it in a thread titled 752 yard 3 shot group . You can take a look at it there . I don't know if i can fix it or if I should just hange it on my reloading room wall to get grins and giggles from all of the deer slayer friends that come over to visit .

How I found out that it lied was I used my NF software to correct my drop and match up with my real world data . I'm kind of leaning towards just matching my drops with the real world data that I gather from the target and adjusting it with my NF SW if that makes any since ....

BigBuck
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