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Reloading Berger Bullets


Help interpret first chrony data

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Unread 05-29-2008, 04:48 PM
Silver Member
Join Date: Apr 2007
Location: Colorado
Posts: 332
Not bad groups, seem pretty good.
I prefer IMR4064 - 42.5 - 43.5 gr load - 175 BTHP match sierra. .308 caliber
I also use Federal Gold Metal Match brass and Winchester large rifle primer.

SD I prefer less than 50 FPS 100 MAX but as always the closer the better.
I understand the magazine and chambering regarding your bullet length.

I still adjust this to find the sweet spot then see if you can cycle the rounds
you will most probably still be OK.

Hope that Helps best of luck keep up the good work.
Location, Location, Location - Send It
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Unread 06-04-2008, 12:14 PM
Bronze Member
Join Date: Nov 2007
Posts: 45
Thought I would provide an update:
Looking at the numbers and the insight provided by this board and others I changed some things:
a) gave my rifle a really good copper cleaning which it hadn't had in a few rounds.
b) choronographed earlier in the day with more light and total overcast.
c) got a digital scale. I've never been really comfortable with my working of the balance beam so I got a Lyman 1000 grain scale.
I loaded up the same batches I ran through the last time and got much better numbers in terms of standard deviation and extreme spread (assuming I'm doing my math right). Here's the best one:

1) 2689 fps
2) 2692 fps
3) 2686 fps
4) 2681 fps
5) 2690 fps
6) 2692 fps
7) 2682 fps
8) 2694 fps
9) 2701 fps
10) 2691 fps
Avg Vel 2689.8 fps
Extreme Spread 20 fps
Deviation 5.55 fps
10 Shot group size 0.717 inches
10 Shot group MOA 0.685 MOA

The group size got pushed out just a little bit by two hits that landed on the outside edge of the grouping, otherwise it would have been .5 inches. But at the time I had called them as flubbed shots so its something for me to work on.
Thanks for all the help guys.
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Unread 06-07-2008, 08:48 AM
Bronze Member
Join Date: Mar 2008
Location: Alabama
Posts: 66
What is the purpose of this gun/round combo? From the looks of it, it suggest this is a paper puncher/target combo? I guess if you're going to punch paper inside 300yds, your velocity, or SD's wont make that much difference. Accuracy will rule. Im not a BR shooter, but understand they don't really care about SD as long as the accuracy is there. SD will become important at longer ranges though, but we're talking long range, and how precise do you want to be at those ranges. If you're SDs are in the 20fps range, unless you're trying to create one hole at 1000yds, I doubt it will make much difference. Probably none at all on plates out to 600yds. Others may have different ideas.

Bottom line is I'm not sure what you really want interpreted?

I do have one question from looking at a couple of the 5 shot strings...are you letting your bbl cool down sufficiently?

Do you weight each charge individually?

And, though I'm not a .308 loader, this "rule" holds true mostly across the board, or at least is my rule of thumb...use a powder that is fast burning enough to generate max velocity, but slow enough that the max velocity is attained at 90% or greater case fill. I think with the loads you listed, you're right at that with Varget. R-15 might be another choice. IMR 4064, BL-C(2) Also.
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