Can 0.1grain make this much difference

Generally no, a tenth of a grain with 4064 isn't going to be that amazing. Doesn't mean it can't happen, just that it isn't normal.

Also I think you can bump up the charge a bit more too and see if that doesn't help the accuracy tighten up. 4064 is a very forgiving powder for 8x57 Hodgdon lists 45 gr compressed as max, and I've used that under 185gr Rem bullets with good accuracy.

What you want is a load that doesn't change significantly between .3 grains spread. Finding that one perfect load that needs to be held to a .1 spread means you are on the "ragged edge" of accuracy. So a rise or fall in temperature, or angle of the rifle as fired, and it can all go away.
 
IMR4064 is pretty long grained powder, I would expect ~.1 grain variation from throw to throw of even a good powder measure.
 
What you want is a load that doesn't change significantly between .3 grains spread. Finding that one perfect load that needs to be held to a .1 spread means you are on the "ragged edge" of accuracy. So a rise or fall in temperature, or angle of the rifle as fired, and it can all go away.
Click to expand...

+1 Jimro.

My thoughts are a tenth of a grain difference is general not going to make that kind of difference but even if it is that is not the load you want unless you can ensure that the temperature, humidity, and elevation are all the same.
 
emcon5 said:
IMR4064 is pretty long grained powder, I would expect ~.1 grain variation from throw to throw of even a good powder measure.
Click to expand...


Exactly! Only way to know of a for sure .1gr difference in charge, is to have one of those scales that weigh down to the .02gr, and a kernel or two will change charge weight.
 
Don't change any thing. Now see if you can do it again. I think it's a good load but what did you do to get the rifle to get it to shoot? Check the rest, stock and hold. If you can find what changed you should be able to do it again. Otherwise forget about it.
 
I'll state upfront that I have no evidence or background to support my thoughts on this.... But I doubt powder burns efficiently enough for 1/10 of a grain To make any difference. Measure 1/10 of a grain and put it in a pan.. I bet 2/10 wouldn't make much of a difference, especially on a load of that size.
 
I weigh a lot of IMR 4064 with my Redding beam scale that has hash marks of .1gr increments . One avg kernel of 4064 will move my scale 1/4 to 1/3 of the .1gr hash mark . So .033gr-ish I can see when I weigh charges on my Redding scale . Those hash marks come in very handy when weighing pistol loads that are almost always something .what ever grains . I also use check weights .
 
So 3-4 granules of powder is 1/10 for 4064, I doubt pressure or velocity is effected. Still hard to believe powder burns that efficient.
 
Can .1 grain powder make a difference? Absolutely. I shoot highpower rifle and have noticed this at 500 and 600 (more noticeable at 600) yards with SMK 80 gr .223 loads. I use 23.4 gr of 8208 XBR and as long as I do my part I can hold 9 ring or better all day long, exceed that by .1 gr of powder and accuracy is erratic. Dropping the charge down I don't notice anything until I hit 23 gr of powder then it starts to become erratic again. One shot could be X, next could be a 7. I weigh every charge on a RCBS digital scale. I have tested this from a rest as well as prone position, its definitely repeatable and predictable. At shorter distances like 200 and 300 it doesn't seem to make a difference at all.

Will it make a difference with every gun/bullet/powder combo? Probably not. I'm going to say probably very few cases where it makes a difference.
 
Ok let's for arguments sake let's say it does. What other things are more influential and also have to be perfect for .1 gr to make a difference. Does a case weight difference of 2% have more effect? Are you weighing cases and only using those are exact? What about primers? Are you using match primers ? And does the variation there have more influence? Are you weighing bullets? You get the idea. What about other environmental influences, wind, barrel temp , were they all exactly the same? .1 gr may make a difference in a pistol charge, ie 3.1gr of 231 but struggle to believe it does on a typical rifle charge or any charge where it is less that .5% say. Let's also not forget, this wasn't 600yds, it was 100yds.
 
Don't let the nay-sayers rain on your parade. You have achieved a level of shooting zen that would make the Dalai Lama jealous. The fact is, there is an optimal accuracy synergy between your new load and your ability to shoot well, regardless of the physics or ballistics involved. Embrace the mind-rifle-cartridge meld and enjoy it in the future. If you can't achieve the same accuracy next time, it's only because you have not yet yielded to the synergetic triad of mind, rifle, and cartridge. :D
 
I think the first response answered the OP pretty well. Below is a random 1000 shot group generated by computer. The first, second, and third groups of three are also shown (shots 1–3, 4–6, and 7–9). Note that one is larger than the others and that the POI's are not in the same place. It's just as easy for one to smaller than the others. This is just how randomness works.

There are, of course, non-random influences in actual shooting, but this still illustrates how randomness can fool you into drawing an unjustified conclusion. It's why groups of ten tell you a tighter version of the truth than groups of three do. Ten gives randomness more opportunities to even things up, and it tends to. You can also combine several smaller groups to get the same effect.

first3of1000_zpsb52206f1.gif
 
Unclenick and others have covered this well, it is my opinion that you have encountered issues with a small sample size. And who has not?

Recently I was testing my 270 Win trying to find an accurate 130 grain load. I have gotten lazy in my dotage and I am firing five shot groups, then if the load shows promise, I will come back and shoot 10 shot groups.

My best 130 grain bullets groups are these. Not particularly great, but fine for hunting.






I did not scan the evil target. I shot one load that the five shots clustered tightly. I was certain I had finally found the 130 grain bullet load for this rifle. I loaded 20 rounds to verify, came back to the range and started shooting. It was awful, much larger than the above targets. Because the load was doing so poorly I decided to make it a twenty shot group. I don't feel like scanning that target, not worth bragging about. But the thing is, as Unclenick is showing, randomness and small sample size will create the occasional great looking target. A bad target is a bad target regardless of sample size, that should be obvious.

I like to rail about gunwriters, their current "Gold Standard" is a three shot group. This is primarily due to their laziness and their economic incentives. From what I have read, they get paid a flat rate per article, lets say $400.00. It is in their economic advantage to spend as little money and time shooting at the range. Bullets cost money, powder costs money, time is money, so the buggers shoot three shot groups, claim that is all anyone every needs to shoot to determine load accuracy, and of course, what they say is nonsense. It leads to nonsensical data. I read one article of cast lead bullets in a 30-30 Marlin leveraction in Rifle magazine. The author had three shot groups which were not merely MOA, but sub half MOA. If Marlin lever actions were capable of shooting consistent half MOA groups with cast bullets, reduced F class matches would be populated with the things. Long range shooters would be using the things for a grin. Lever actions would a standard for accuracy. But, they are not.

Unfortunately my FN Deluxe only shoots 150's well, and for a hunting rifle, I think these ten shot groups are sufficient. Wish I could get the velocities up, I can push a 150 grain bullet in a 308 Win faster.



 
Slamfire,

I agree with you on three shot groups. But then again, those lever action rifles were meant for hunting, not target shooting, so three shots in a tight clover are fine performance for their intended purpose, as long as those three shots are repeatable from a cold rifle.

And I'd rather carry a handy lever action around the woods than one of my heavy target rifles, even though I know it won't print as tight over ten shots.
 
You must log in or register to reply here.
Back
Top