I am shooting a 6.5 creedmoor the savage 10. Obviously not a custom rifle but shoots good. I am working on some hunting loads. I was shooting under 1 moa with 120 gr amax. Trying 143 gr eld-x. For deer round. Got a group yesterday after two other loads if five rounds that measured .62" vertical. Today I shot the same load and was 1.4". Also shot through a chronograph yesterday showed S.D. Of 4.9 today 13.4. Today the barrel was probably cooler only having 3 fouling rounds before group. Should I be shooting cold barrel groups and waiting an hour before trying new loads. Will the hot barrel yesterday be shooting that much more consistent? It will be a cold barrel while hunting should I scrap that load?
New to loading. I get different groups with same load
- Thread starter Shayne w
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Heat, humidity, depth on your ogive, distance off the lands, factory brass versus quality brass. All can affect accuracy. Did you precisely measure each round, weigh each bullet? Some powders are more temp sensitive. I learned a lot from The Handloaders Bench. (google it.) Honestly, I had some similar results until I started neck loading my rounds and bought quality brass. Tons to learn.
The mods should probably move this to reloading where it will get more response.
But in the meantime, a million things can change group sizes and SD is a statistic that takes more than 5 shots to fully become valid.
Maybe something did change between you (cheek pressure, shoulder pressure, trigger squeeze) or the environment (lighting, wind, different target type) that day. I don't think that your results are that abnormal. Try again and report back
But in the meantime, a million things can change group sizes and SD is a statistic that takes more than 5 shots to fully become valid.
Maybe something did change between you (cheek pressure, shoulder pressure, trigger squeeze) or the environment (lighting, wind, different target type) that day. I don't think that your results are that abnormal. Try again and report back
Sunray
Member
Like Laphroaig says there are multiple reasons for inconsistency. One of which can be whether or not a wood stock is sealed on the inside. Especially the barrel channel. Moisture from ambient humidity can and will cause a wood stock to expand and contract causing the barrel and receiver to move. Any wood sealer found in any hardware store will do.
"...should I scrap that load..." Not if it's consistent. 1.4" at 100 is nothing to sneeze at either. A deer rifle doesn't require MOA accuracy. It does require consistent accuracy. A rifle that shoots a 3" group at 100 all day, every day is a great deer rifle.
Chronographs don't really tell you much. The average velocity doesn't matter and neither does the standard deviation. Those don't mean anything at all if the groups aren't consistent.
"...should I scrap that load..." Not if it's consistent. 1.4" at 100 is nothing to sneeze at either. A deer rifle doesn't require MOA accuracy. It does require consistent accuracy. A rifle that shoots a 3" group at 100 all day, every day is a great deer rifle.
Chronographs don't really tell you much. The average velocity doesn't matter and neither does the standard deviation. Those don't mean anything at all if the groups aren't consistent.
Lafitte
Member
This is my opinion and will be opposed by many. After shooting the .62 group you probably cleaned the barrell. Shoot it until the group opens up, THEN clean it. Just my opinion.
Lafitte
Lafitte
Varminterror
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How many shots in the chronograph average on each day? How many groups were fired each day? Shooting one .6moa group and one 1.4moa group is pretty simple - one day was a random stacking of a low integrity sample set, the other day was an equally low integrity sample set, both of which fell with under the standard group size for the rifle. If the rifle shot ten 5 shot groups, all of .6moa on the first day, then ten of 1.4 the second day, I'd be more worried, but I assume such wasn't the case.
Usain Bolt doesn't run a world record speed every time he puts on his running shoes. Rifles don't shoot their maximal precision for every group, and shooters don't either.
Usain Bolt doesn't run a world record speed every time he puts on his running shoes. Rifles don't shoot their maximal precision for every group, and shooters don't either.
MutinousDoug
Member
The OP defined the number of shots in the group he was shooting as 5 rounds. May I suggest that 5 shot groups do not reflect the likely group size the gun is capable of and that 10 shot groups may more accurately show the capability of the rifle/ammo system?
Standard Deviation calculations on groups of less than about 25-50 shots are just about meaningless as the OP's data suggests.
Standard Deviation calculations on groups of less than about 25-50 shots are just about meaningless as the OP's data suggests.
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