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03-11-2014, 07:10 PM
(This post was last modified: 03-11-2014, 07:13 PM by dsw0007.)
I went to the range and shot these groups.
5 rounds each @ 100yds
123SST's, Leverolution, Hornady brass, Federal 205's, 2.270" COL
All from bipod with rear bag.
[ATTACH=CONFIG]4831[/ATTACH]
I'm attaching a pic showing all four groups and I can post individual groups if you need close ups. I'm still fairly new to the load development game so I don't have everything down pat quite yet. I'm fairly confident that we're looking for minimal vertical dispersion, and not necessarily concerned with horizontal dispersion at this point, correct? The charges from left to right: 30.3, 30.8, 31.3, and 31.8. To me, it looks as if the 30.3 and 31.8 are the charges where I'm getting close to my node, agree? The outlier shots in the first two groups were all on me (1st shot of 1st group and last shot of second group, pulled both anticipating trigger break, still getting used to the new two-stage). I'm at my max COL so I can only shorten that to maintain use of the magazine. I've got light ejector marks at 31.8 so I might be able to get away with going up to 32.0 but wouldn't feel comfortable at all going above that. I don't have a chrono or means by which to measure pressure. I know that there is some sort of computer program to use than can calculate ES and SD but I don't remember what it is. Any help at all would be greatly appreciated.
Thanks
No war is over until the enemy says it's over. We may think it's over, we may declare it's over, but in fact, the enemy gets a vote. - Gen. James Mattis
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nice groups! Get a Chrono, you are missing out on a lot of data and you will want to know the pressure as well. I would run the 30.3 over a Chrono and the 31.8. I just did an OCW today and I didn't have any ejector marks on my brass at 31.7-31.9 but the primers were flattening.
Now try the 30.3 at 300 yards and see how it groups then. I do an OCW then fine tune at 300 at least. I have had groups that were almost 2" at 100 yards that would group sub MOA at 300 in a .308. So I always confirm my loads as far as I can to see how they truly perform.
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Good shooting. I second the chrono.
Do you have a range where you stretch out to 200 yards or beyond. I do all my work ups with the Grendel at a minimum of 200 yards. It's a lot easier to identify your nodes at that range.
It does look like you've got a good node there from 30.8 to 31.3.
8541 Tactical put out a good video on nodes, I want to say within the last 6 months. I'd check that out if I was you.
"Those who sacrifice liberty for security, deserve neither." Benjamin Franklin
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Thanks guys. I'll check out the videos. Unfortunately, I don't have access to a range that is over 100. And to be perfectly honest, I'm not even sure that the range I do have access to is a true 100 yards. I'll be shooting in a steel match (to 1000yds) once per month, next match being in May and then every month thereafter till September, but I only have access to it on days of the matches.
No war is over until the enemy says it's over. We may think it's over, we may declare it's over, but in fact, the enemy gets a vote. - Gen. James Mattis
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03-11-2014, 09:45 PM
(This post was last modified: 03-11-2014, 09:50 PM by Dave Bob.)
To find the ES (extreme spread) and SD (standard deviation) you have to have a chronograph because you have to measure the bullets speed. The extreme spread is the difference between the fastest and slowest speed in a string of shots. Standard deviation is a formula you can calc it here http://www.calculator.net/standard-devia...lator.html or setup a spreadsheet to do it. Good groups also. Also forgot to add most chronographs will figure it for you.
Dave
Nice groups right off the bat. Since you are going to be competing, you will really need to see what's happening at 300yds with your groups. You will also need the chrono to see optimum Extreme Spread, and plug your velocity data into a ballistics program.
You will want to know the barometric pressure, temperature, and humidity when calculating accurate trajectories for your boom stick, especially for a match. Get that into a density altitude function, and you will have very accurate data for the load once you have a load that you have settled on.
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Looks like you will be spending some money on a Kestrel, Chrono (or a version thereof) and an app for your phone to do the SD calculations. Also, a range finder. I hope your wife understands why you need all these things.
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Nice groups, I'll second the opinion on getting a chrono. I got my Magnetospeed for Christmas and I don't know how I got along without it.
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Dang that's purty very nice
Hey I'm not a complete idiot I have parts missing. Though some times I wonder.
Grendellizing predators as of the fall of 2012.
Small bullets that go really fast, make me giggle........... 
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Nicely done! +1 on the chrono; once you have one you will wonder how you did without it.
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Thanks for all the advice, guys. I'll have to work on getting a chrono and finding a little bit longer range to work on. Getting married in May so this may take a little while. Will keep you updated with any changes though. Thanks again!
No war is over until the enemy says it's over. We may think it's over, we may declare it's over, but in fact, the enemy gets a vote. - Gen. James Mattis
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There's still time before the wedding!
heinz57grendel
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I do all load development at 300 yds. I see better results and this round really shines at distance. Magnetospeed chronys are nice but do affect accuracy a little bit requiring you to load an extra round in order to find velocity then load five more to print a group with no interference on the barrel. I still use the old "shooting chrony"
Klem Wrote:There's still time before the wedding!
Good advice.
dsw0007; great groups! +1 on the magnetospeed, love mine. What's your barrel length, twist and the approximate temperature when you tested? I got some Leverolution and want to try it under some SST's.
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26" 1:8 61f
No war is over until the enemy says it's over. We may think it's over, we may declare it's over, but in fact, the enemy gets a vote. - Gen. James Mattis
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Werd
No war is over until the enemy says it's over. We may think it's over, we may declare it's over, but in fact, the enemy gets a vote. - Gen. James Mattis
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