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Post by junglere on Nov 5, 2015 11:42:22 GMT
For year on hand load when using the chrono id be looking for the best speed possible with the smallest ES. Fairly straight forward logic, speed equals less drop and a more consistent speed equals less vertical range so better accuracy.
On this credence all my load development was based.
till now! Some strange results! Worked up a simple load in the 300 win mag, pushing a 208gr amax at 2904 avg but with a crazy ES of 115! I'd expect it to not shoot well at distance as it was only managing around the inch at 100yrds. Only had chance to take it back to 500yrds (working out drops for a few other rifles also) but I was surprised that once I had it dialled in every shot I could ring the 4x3" plate. It's confused me slightly and tiff and I had a chat in which he also said his 338 lap mag also had a triple figure ES yet held consitantly 1 Moa out to a mile. Looking forward to seeing how it behaves in the next 1000m additional range.
any idea why this would be? If this is the case then is there any point at all in chasing a tight ES?
thougts and comments sought
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Post by oaken on Nov 5, 2015 14:11:26 GMT
VooDoo!
I have shot tiny groups with huge velocity variation and dreadful groups with impressive ES.
Very easy to get obsessed when you first get a chronograph, I only use mine now to get a quick velocity confirmation to work out my drops. Drops that are then confirmed with field testing.
IMHO a ladder test (or OCD if you prefer) is best way to fine tune your accuracy.
Personally, from scratch, I load at .3 gr increments to find where pressure starts, then ladder test at .3 increments up to the limit for MY rifle to find the accuracy node. I will stick with that node even if it is quite a way below the pressure limit. Only then will I chrono the load!
Works for me and I reckon a lower velocity accuracy node is good for both accuracy (consistency) and barrel life :-)
Interested in theories about your findings though I reckon a fair few of us have found the same and no longer worry about it ;-P
AtB
Rup
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Post by sako75varminter on Nov 5, 2015 15:43:39 GMT
Good advice from Rup!..i do pretty much the same but load in .5 increments,and always ladder test!...as for your accuracy findings Will...some bullets get better the further you push them out...i.e..1MOA at 100yrds but then stabilize them selves to give 1/2MOA at 500...yep its a head cracker!  |
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Post by Jungle-re on Nov 5, 2015 16:58:32 GMT
Yeah I develop the same using 0.3 v started with 0.2 but it was just too many rounds. Loads are only tested at 100or 200 though as that was the club at sever side I had access to. With the round house being close that's likely to change now.
I'm glad I'm not the only one it just seemed that was one hell of a variation logic says its shouldn't shoot at distance.
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Post by tisme on Nov 5, 2015 17:03:01 GMT
ES matters less than people think.Here's some figurers run through strelok A .308 shooting at 2770fps @500 yards = 10.2 moa the same bullet at 2870fps = 9.5 moa. just over 1/2 MOA difference or 2.5 inches. So a five shot group with a round with an extreme spread on 100fps can still group at nearly 1/2 moa, it might just be harder to do. The fact that even a low wind of 5mph with full value will alter the same shot by just over 2 moa is a lot harder to control.
A bigger rifle like you're 300 win or Tiffs .338 will have even less effect on group size due to es
Time spent reading wind I think is more important than hours loading
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Post by c18rch on Nov 6, 2015 12:17:12 GMT
Always go for the most accurate load and not the one with the lowest ES. ES is not always an indicator of accuracy. You have to consider the things that may be causing the change in the velocity too.
For example, a slightly heavier bullet (I'm talking the variation within a batch now, and not different bullet types) will have a lower velocity in theory but should also have a higher BC and therefore despite causing a difference in ES may not show as a change in POI on the target. However, if that change in velocity is because of a lower charge weight, then it may do.
ES still needs to be considered. Especially at long range. Eg, using my 7-08 162 A-Max Load, at 1500yds doing 2550fps the drop is 78.4 MOA. At 2560fps so only 10fps difference, the drop is 77.7 MOA. 0.7 MOA, but that is nearly 11 inches, or a third of the fig 12 that we shoot down at bodmin. A 20fps ES would be 1.5 MOA difference. The 115fps that you are getting will be 9 MOA (11ft) at 1500 yds!
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