Good groups bad numbers

[SeabeeKen]

New 6XC giving me a bit of a fit. Been testing different powders with Sierra 85 gr BTHP for varmint hunting. Ive been getting groups as small as .1" but my ES/SD aren't that great, ES varying from 15 fps to 100. I have not played with seating depth yet. Brass is twice fired Peterson. Testing 3 other powders today and then decide which powder and then seating depth tests. Bumping shoulders .0015 and necks over a mandrel, scope is a viper pst, rifle is a savage 110 sa with preferred barrel blanks 10T 5R barrel. scope and action screws good. I have several great groups but the numbers aren't great. Tighter neck tension? Seating depth? I've always been told that good numbers and bad groups can be corrected with seating depth and the reverse fixed with a powder change. I've tried 10 powders in this rifle. Dropping back and rethinking this. Frustrating

 

[Jager]

Me thinks that if you're getting groups around 0.1" in a hunting gun... you're done. Actually, you're more than done. Go buy a lottery ticket!

A bunch of years ago Speedy Gonzales had a benchrest rifle with a hummer barrel. Speedy was eating up the matches he entered with that rifle. And it was largely because of the results from it that Virgil King asked him to bring it to the Houston Warehouse.

The ES of that gun of Speedy's was around 70.

 

[RegionRat]

I'm having a hard time following the post. I'm dyslexic and a bad writer myself, so please don't take that the wrong way.

When you say ..." I have several great groups but the numbers aren't great."... are we talking about great groups but bad speed stats?

If your groups are in the ones, and your speed stats aren't that good, your next step is to test the groups at the longest distance you plan to shoot.

An ES of 100 isn't good I will agree, and if you are weighing powder it really should be better, but the group size at the longest distance is your priority.

If the distance creates a poor vertical spread due to the speed stats, then we have something to go after.

 

[Coyotefurharvester]

And if vertical dispersion doesn't occur, the velocity readings aren't accurate. And of course load work would be done.

 

[357Mag]

New 6XC giving me a bit of a fit. Been testing different powders with Sierra 85 gr BTHP for varmint hunting. Ive been getting groups as small as .1" but my ES/SD aren't that great, ES varying from 15 fps to 100. I have not played with seating depth yet. Brass is twice fired Peterson. Testing 3 other powders today and then decide which powder and then seating depth tests. Bumping shoulders .0015 and necks over a mandrel, scope is a viper pst, rifle is a savage 110 sa with preferred barrel blanks 10T 5R barrel. scope and action screws good. I have several great groups but the numbers aren't great. Tighter neck tension? Seating depth? I've always been told that good numbers and bad groups can be corrected with seating depth and the reverse fixed with a powder change. I've tried 10 powders in this rifle. Dropping back and rethinking this. Frustrating

Seabeeken -

Howdy !

You might bias you cartirdge load acceptance mostly towards attainable group size, operating w/o inputs from a chronograph.

Let's say you are likewise happy w/ things like flatness of the bullet's trajectory, and terminal performance obtained w/ the chosen bullet. Would you change things if say...... the Mv was shown to be lower than what you expected ?

IMHO:
If groups are that good.... " why ask why " ?!


But hey.... that's just me.


With regards,
357Mag

 

[Ned Ludd]

As has been noted - determine precision at the longest distance you intend to shoot. Even if that is 500-600 yd, you may find the excessive ES/SD isn't great enough to prevent acceptable precision. At 1000 yd, ES/SD that high would likely be a problem, but you're probably not shooting animals at anywhere near that distance. Test it, then you will know.

 

[NorCalMikie]

I've been getting groups as small as .1"

So, what's the problem? Dead critters don't know or care about ES or SD.
All going in the same hole?

 

[KMart]

Which chronograph are you using to measure your speed?

 

[Bill Norris]

Let your target tell you the truth. Them numbers can be very deceiving to say the least. The chrono learned to lie as bad as Joe Biden.

 

[Ga. Dawg]

Chunk the chronograph. The target is the determining factor!

Mike

 

[SeabeeKen]

Which chronograph are you using to measure your speed?

Labradar. Never had an issue with it. The es sd bugs me because ive always been able to get good numbers and good groups. Im going to shoot the 3 best loads again and see if they repeat and go from there. Thanks for the opinions and advice.

 

[ebb]

You don't need no stinkin numbers. They do not give out fake wood for the numbers just the most in the middle or the smallest group

 

[JEFFPPC]

Has anyone ever seen the trophies for ES and SD? Or for most chronograph strings? I wonder if it's related to the old saying, "Those who can do, those who can't teach."

 

[6.5 forever]

You may get good groups at short range testing with bad ES numbers. But with that big spread in ES long range shooting, you will have accuracy problems.

But bench rest short distance is more forgiving for those ES.

 

[WyleWD]

New 6XC giving me a bit of a fit. Been testing different powders with Sierra 85 gr BTHP for varmint hunting. Ive been getting groups as small as .1" but my ES/SD aren't that great, ES varying from 15 fps to 100. I have not played with seating depth yet. Brass is twice fired Peterson. Testing 3 other powders today and then decide which powder and then seating depth tests. Bumping shoulders .0015 and necks over a mandrel, scope is a viper pst, rifle is a savage 110 sa with preferred barrel blanks 10T 5R barrel. scope and action screws good. I have several great groups but the numbers aren't great. Tighter neck tension? Seating depth? I've always been told that good numbers and bad groups can be corrected with seating depth and the reverse fixed with a powder change. I've tried 10 powders in this rifle. Dropping back and rethinking this. Frustrating

I think you're WAY over thinking this for a hunting rifle.......information overload. A 6xc 10tw shooting an 85gr Seirra HPBT is the basic recipe for a very, very good shooting hunting rifle. The XC is one of the easiest cartridges to find a load for (especially a hunting rifle). For your application and bullet choice A powder in the general burn rate of R-15, or 4064 is a great place to start. Choose a couple and do a load workup on them. Keep in mind that for a hunting rifle the first shot out of a cold bore is most important and in a hunting situation you probably won't have a chronograph in your backpack. JME. WD

 

[Doom]

The ES and SD number you quote represent what number of shots? Statistically a ES of 100 could well occur for a large number of shots with a SD of 17.

 

[piie]

Have you tried different primers? ES/SD on shorter distances with great groups are no issue, it's at long distance that the SD will probably manifest in the vertical.

 

[boltfluter]

If in doubt, find a friend and shoot over two chronographs. I would be surprised if one was not wrong. Good luck.

Paul

 

[Firearmsunlimited]

It could be a primer issue or a issue with your Labradar. There have been reported issues with Labradar but without a proof channel it would be almost impossible to ascertain if the chronograph is the issue.

 

[Dusty Stevens]

Hows the ignition working on that savage? How does each dry fire sound- does 10 in a row sound exactly the same snap?