Would you prefer a 1" vertical string group or a 1" horizontal string group?

[deadidarren]

I've scratched my head many times with this due to both scenarios and personally don't except either. I'm not a competition shooter but I do and will do everything possible to achieve completion accuracy out of my hunting rigs. I like to push the limits on distance and want to take everything out out of the equation other than me, the fool squeezing the trigger. I hunt exclusively with over bore cartridges for whatever reasons and it's a constant battle. Seating depth in most cases is the culprit but I've also had charge weights come out of the node without a reasonable explanation. With a new barrel after 50 to 75 rounds, I'll do a simple ladder test and pick a flat node in the middle and it usually will hold for the life of the barrel. However, last year I had one go from go from low single digits ES to over 20 within 20 rounds and the barrel had less the 500 rounds through it. Started back from scratch with a new ladder test it's now back to where it was albeit at a higher node.

With me if it's a new custom barrel 50 rounds if it's a factory rifle I'll shoot 100 rounds then I will do load development.

 

[skipglo]

Try a few loading up and down in .2 gr increments and see but with all the other factors coming into play it will be hard to notice any real difference if it's improving.

Noted!

 

[Les in Wyoming]

Grateful for all the input. When I upped it .3 grains it spread the group all over the place. I might try bringing it down .2. The horizontal group has a seating depth of 3.610 (CBTO) The vertical group is 3.605. Seating the bullet at 3.603 made a huge group. (Amazing what .002 can do). I can only go up. I will try 3.607.

 

[Rflshootr]

Grateful for all the input. When I upped it .3 grains it spread the group all over the place. I might try bringing it down .2. The horizontal group has a seating depth of 3.610 (CBTO) The vertical group is 3.605. Seating the bullet at 3.603 made a huge group. (Amazing what .002 can do). I can only go up. I will try 3.607.

How often do you clean the bore? What size groups did it shoot before you had problems?
How many rounds through the barrel? Also check your crown for damage.

 

[FURMAN]

Vertical is powder
Horizontal is seating depth

This is simply not true or at least not that simple. Both powder and seating depth effect the group in both directions. I have no clue where you got that. I am guessing from 6ppc guys shooting at 100 yards.

 

[Rflshootr]

duplicate deleted

 

[tim_w]

So 3.605-3.610 is the gross jump/depth node. Try 3.608 as you want to try to stay on the + side to allow for throat erosion.

Sounds like you know the upper limit on powder. With the 3.607-8 CBTO now drop powder to find bottom. Then split for the middle.

Be interesting to know how far it's jumping to the lands.

Neck tension?

 

[nralifer]

I did a search and could not find this particular topic. My Ruger m77 30-06 used to shoot sub MOA groups but somehow lost its accuracy. Started over and bedded it. My old load seems to be right, but have been chasing seating depth. Found a node. When the bullet is seated at 3.610 CBTO, it shoots a 1" horizontal group. This is OK for hunting, seeing I use my 300 WM for precision. But I am kind of spoiled with shooting a ragged hole at 100 yards. So I pushed the bullet down another .005 (3.605 CBTO). This shoots a vertical pattern 1". I was going to just leave well enough alone and load up a bunch. But . . . it nags at me. From what I understand, horizontal and vertical stringing are seating depth issues. Not sure which direction I should go. Whether to go for perfection or pick one or the other. Would appreciate any opinions. Thanks.

It could be several issues, but the first thing to do is bore scope the chamber and throat and clean the copper thoroughly out of the barrel. I prefer Bore Tech solvents. What you are looking for is evidence of throat erosion. If not too severe you can load the bullet out further.

 

[WildRose]

It could be several issues, but the first thing to do is bore scope the chamber and throat and clean the copper thoroughly out of the barrel. I prefer Bore Tech solvents. What you are looking for is evidence of throat erosion. If not too severe you can load the bullet out further.

I'll reiterate it yet again. Before wasting a lot more time, money, and aggravation I'd get the chamber, throat, and bore inspected.

When a rifle suddenly loses it's accuracy those are the most likely culprits other than loose mounting screws or a loose/busted optic.

 

[Coldfinger]

I did a search and could not find this particular topic. My Ruger m77 30-06 used to shoot sub MOA groups but somehow lost its accuracy. Started over and bedded it. My old load seems to be right, but have been chasing seating depth. Found a node. When the bullet is seated at 3.610 CBTO, it shoots a 1" horizontal group. This is OK for hunting, seeing I use my 300 WM for precision. But I am kind of spoiled with shooting a ragged hole at 100 yards. So I pushed the bullet down another .005 (3.605 CBTO). This shoots a vertical pattern 1". I was going to just leave well enough alone and load up a bunch. But . . . it nags at me. From what I understand, horizontal and vertical stringing are seating depth issues. Not sure which direction I should go. Whether to go for perfection or pick one or the other. Would appreciate any opinions. Thanks.

My rugers that had tang safety were pretty picky on their front recoil lug torque. Start at a lighter torque and adjust 5 pounds at a time and shoot with all other things remaining consistent. Worth a shot.

 

[Lenny Foffa]

My first reaction would be to work up a batch of ammo and start with 9 rounds just touching the lsndsxznd grooves. Record that OGIVE length. !Fire three three shot groups. With equal cooling time between each shot ! That is Bacth 1!! Then with OGIVE number in mind make 9 rounds 5/1000 shorter and record that number ,and Fire three three shot groups . That becomes bacth 2!! Then again 9 Rounds 5/1000 shorter than the second batch!! And Fire three three shot groups!! That is now batch 3 ! Do not alter the load in any way and only change the OGIVEl Length ! I would expect as you approach 25/1000 off the lands and grooves you will see various groups on the Targets ! You may need to fire 5 or 6 groups of 9 ,so for me it would become a second day at the Range to fire a total of 45 rounds ! I would learn a lot from that excersise with that one particular bullet ! All the groups go in the 3 ring binder .that OGIVE length is recorded !! And that's the basis of the hunting. Load ! Next ,if you need too Slightly adjust the powder charge to the Velocity and energy your looking for !! That's my simplistic way of determining when the strings come ! I personally need to record everything !! Each rifle has its own binder ! In case I forget!!

 

[Alex Wheeler]

Just reminding you we do not discuss the ethics of hunting here at all. That's the one subject completely verbotten by Len.

Why?

 

[Alex Wheeler]

I did a search and could not find this particular topic. My Ruger m77 30-06 used to shoot sub MOA groups but somehow lost its accuracy. Started over and bedded it. My old load seems to be right, but have been chasing seating depth. Found a node. When the bullet is seated at 3.610 CBTO, it shoots a 1" horizontal group. This is OK for hunting, seeing I use my 300 WM for precision. But I am kind of spoiled with shooting a ragged hole at 100 yards. So I pushed the bullet down another .005 (3.605 CBTO). This shoots a vertical pattern 1". I was going to just leave well enough alone and load up a bunch. But . . . it nags at me. From what I understand, horizontal and vertical stringing are seating depth issues. Not sure which direction I should go. Whether to go for perfection or pick one or the other. Would appreciate any opinions. Thanks.

Go with the vertical tune and adjust your powder charge. Go up if you can.

 

[WildRose]

Why?

Rule number one here.