Half a grain makes that much difference?

[bsmith]

Here are two groups I shot today. Browning A-bolt 25-06, 110 AB's, all seated to same COAL, 100 yds. The group on the left is with 47 grains of IMR 4350, the one on the right is 47.5 gr. Can 1/2 a grain make that big of a difference? I'm tickled with the group on the left, pretty good for me :grin:

 

[TScottW99]

Had the exact same thing happen with a Remington 700 classic in .308win. A .5 more of Varget made the group go from .25" to a good 2".

 

[kraky]

If you load more up and the situation repeats itself several times over...the answer is yes. Right now one 3 shot group vrs another is almost meaningless....but I would definately keep persuing the good load.
I've done several really outstanding groups from time to time and rushed home to reload another dozen shells......just to find out the load was just run of the mill........the "one hot group" was a fluke.

 

[DrMike]

Yes, a half grain can make that much difference. However, the two groups are within normal parameters. A ten shot group would give you a more accurate appraisal of a given load. If three three-shot loads give similar results at either charge, then you can begin to make a statement concerning group size. However, on the basis of one load, it is really not possible to say much.

 

[rick smith]

Changing loads in that size case by 1/2gr is the way to find those good groups. I would repeat the load several times before trying anything else. Then I would try 0.3gr on either side of that load. Try moving the bullet in/out by 0.005". Have you tried different primers? I have had better luck with WLRM primers in the 25/06. Worth a try. Good shooting, keep it up.Rick.

 

[bsmith]

Thanks for the replies! I now realize that I need to do more work to really narrow in on a good load. Luckily, I love to shoot, I just need to find the time.

The three local shops that carry reloading supplies all carry CCI LR and Winchester LP primers. Even the Walmart that's 25 miles away only carries CCI. Other than mailorder, my choices are somewhat limited.

 

[FOTIS]

Had the exact same thing happen with a Remington 700 classic in .308win. A .5 more of Varget made the group go from .25" to a good 2".

That is not a healthy load to me. A half grain can be a difference of 10 degrees weather diff ----either way (up/down) in the field.