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

[skipglo]

Vertical is powder
Horizontal is seating depth

Vertical is powder....too much or too little? I'm guessing the answer is "yes"..lol... but when you have a 1" vertical shooting 338 lap all bullets touching ( therefore .662 for a 4 shot group c/c) is it worth trying to change it?) My personal question here. Not meaning to hijack the thread! Related question I think?

 

[Bushersam]

Try .2 grs up and .2 grs down from present load and see what happens.

 

[skipglo]

Try .2 grs up and .2 grs down from present load and see what happens.

Thanks Brother! ( I figured the answer was Yes...) .2 is reasonable...I will give it a test drive today!

 

[Bushersam]

It's a hard rabbit to catch but you're close. With components the way they are it's hard to experiment a lot.

 

[Chadp82]

I would also double check the rifle itself. It was mentioned you started over and bedded it. You probably did, but double check torque on things in both the rifle and scope.

I chased my tail a few years back on a rifle as to why the grouping opened up and found 1 scope screw that was snug but not quite at the recommended torque. My problem went away after that discovery.

 

[emp1953]

Depending on the powder you use, the magnum calibers are known for creating a carbon ring in the throat, quicker than non-magnum calibers
[1] I would scrutinize the throat. Carbon build up there will play havoc with poi changes.
[2] This one is simple - hand the rifle to another shooter and have them give it a go.
[2] Next is something very simple as well. The next string you fire DO NOT USE THE MAGAZINE. Manually feed one round at a time. Allow 8-10 minutes between shots. Could be that recoil is causing bullets to jump back into the case.
[3] Did you add a muzzle break, a bi-pod?
[4] Is the point of impact of the first shot always dead on or is that also off from where it used to be.
[5] Check the crown of the muzzle, use a Q-tip and slide the cotton part in and out of the muzzle see if anything catches on the cotton.
[6] Is it a variable power scope, are you changing power settings between shots? Verify the torque of all the scope mounting hardware. Did you shoot those strings in hot weather? I've seen ammo perform really differently when left out in the sun, on a shooting bench for 10 minutes or so.
[7] When all else fails put a known good scope on and try it out

 

[Rflshootr]

Vertical is powder....too much or too little? I'm guessing the answer is "yes"..lol... but when you have a 1" vertical shooting 338 lap all bullets touching ( therefore .662 for a 4 shot group c/c) is it worth trying to change it?) My personal question here. Not meaning to hijack the thread! Related question I think?

Typically, you add more powder in small amounts to tune vertical out, if the rifle will allow it. Also, you can seat the bullet deeper into the case in small amounts to do the same thing. You are reducing the capacity of the case which is pretty much as the same as bumping the powder charge. Myself, I usually bump powder if I can. On a big case like a 338, I'd go up in .3 increments.

 

[WildRose]

Vertical is powder....too much or too little? I'm guessing the answer is "yes"..lol... but when you have a 1" vertical shooting 338 lap all bullets touching ( therefore .662 for a 4 shot group c/c) is it worth trying to change it?) My personal question here. Not meaning to hijack the thread! Related question I think?

If all are touching, you're probably not going to improve a whole lot over what you have but you can always try.

 

[Tommo64]

I would suggest that if it is related to seating depth, if you were previously shooting ragged holes but now have stringing, you try seating further out a little, as the change may be due to throat erosion.

 

[WildRose]

I'm still thinking the smartest move that reduces the chances of burning up a lot of components that are expensive and in short supply for no gain would be to have the chamber and barrel inspected with a scope.

I would not be the least bit surprised if it's either erosion, fire cracking or a bad carbon ring since the loss of accuracy was rather sudden.

At least then you know what you are working with.

 

[Window]

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.

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.

 

[skipglo]

Typically, you add more powder in small amounts to tune vertical out, if the rifle will allow it. Also, you can seat the bullet deeper into the case in small amounts to do the same thing. You are reducing the capacity of the case which is pretty much as the same as bumping the powder charge. Myself, I usually bump powder if I can. On a big case like a 338, I'd go up in .3 increments.

Thank you!

 

[skipglo]

If all are touching, you're probably not going to improve a whole lot over what you have but you can always try.

That's kinda where I'm at in the thought process too! But...hey...I'm not going to play anymore with seating....boys say it's powder! It's easy to throw a few loads with a little more powder.. (or not...might be drinking too much of the Kool-aid!) Used to be happier days when 1.5" was Good enough! Thanks WildRose for a reality check!

 

[WildRose]

That's kinda where I'm at in the thought process too! But...hey...I'm not going to play anymore with seating....boys say it's powder! It's easy to throw a few loads with a little more powder.. (or not...might be drinking too much of the Kool-aid!) Used to be happier days when 1.5" was Good enough! Thanks WildRose for a reality check!

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.