Getting ES and SD down to single digits

[JLDavid]

Not sure if this is the right place for this but I will start here. I am working with a wildcat based on a 7SAUM case. This is set up as a hunting rifle with a sporter stock and barrel with a brake. I am shooting moly 168 Berger Classic Hunter bullets and 66.5 gr of IMR 8133 powder. I use WLR primers in Remington brass. I know that 8133 is way slower than most powders that shooters use for that case and bullet but I have a lot of it. Accuracy is .3" at 100 and sub-.5MOA so far at 200 yards. I can't get my ES and SD down around single digits which from what I read is key in long range accuracy. What do you guys do to tame these variables? Any help is appreciated.

 

[cjuve]

I shoot groups at the distances that I intend to hunt at and if the 1/2 MOA accuracy is consistent in don't worry about the ES/SD. Chasing numbers on a chronograph is a good way to waste time and components.

 

[JMW67]

^^^ This and if it does not work try a primer change and sort and prep your brass very well neck tension can cause this also

 

[JLDavid]

Thanks for the quick replies guys. While the weather is decent I would like to work out to 800 yards and see how accuracy holds. I have a friend with an annealer so maybe running the cases through will help even out the neck tension.

 

[Rick Richard]

It may be a coincidence, but I found sorting brass by weight provided me with the most consistent ES and SD on my loading results.

 

[just_jon]

Ditching the sizer die expander ball and setting neck tension with an expander mandrel reduced my numbers. So did annealing after every firing. If I were you, I would try a primer change first as it may get you the results you're after without changing any of your other processes. In the event it does not, I would start at the beginning and reevaluate everything.

 

[JLDavid]

On a side note, I bought an expander die and mandrels to use rather than the die expander ball. I removed the ball and sized my case then ran the expander mandrel through the neck. I went to seat a bullet for a dummy round and the bullet fell into the case!!!! Yes, I did have the proper mandral installed in the die. I have emailed the manufacturer to see how this can be remedied. Anyone else have this happen to them?

 

[JMW67]

must have mismarked the expander have you measured it

 

[DoneNOut]

One time I got 5 duplicate reads from a particular load. I figured it was a chronograph error. However, it was working before and after the 0 ES 0 SD! I still have a hard time believing it!

 

[MOOSE39465]

It can be something simple like changing primers or prepping case necks with a brass brush, but I always try to load as many differ powders as I can before going to the range. Usually I will find something pretty quick that I can improve on with minimal effort.

 

[Idaho Lefty]

Thanks for the quick replies guys. While the weather is decent I would like to work out to 800 yards and see how accuracy holds. I have a friend with an annealer so maybe running the cases through will help even out the neck tension.

Try shooting at, 500-600 Yards as it's a bit easier to get, GOOD consistent, groups than at, 800 yds.
A tiny bit of unseen wind, can "screw up", 700 - 800 Yard groups,.. IMO

 

[Reelamin]

One time I got 5 duplicate reads from a particular load. I figured it was a chronograph error. However, it was working before and after the 0 ES 0 SD! I still have a hard time believing it!

Inquiring minds want to know. Well one mind anyway. Was it a one hole group or like the others the load shot?

 

[DoneNOut]

Inquiring minds want to know. Well one mind anyway. Was it a one hole group or like the others the load shot?

There must have been a harmonics problem because I didn't end up choosing it. Bummer

 

[JLDavid]

Try shooting at, 500-600 Yards as it's a bit easier to get, GOOD consistent, groups than at, 800 yds.
A tiny bit of unseen wind, can "screw up", 700 - 800 Yard groups,.. IMO

Will do. I was planning on working my way to 800 with multiple stops along the way. Another reason for this is to make sure my corrections in my rangefinder are accurate and then adjust as necessary.