i cant figure out these groups.

When a rifle with known good performance starts to do irratic things, I start from the basics and make sure nothing simple but hard to see, is at fault.

A great shooting F Open rifle started to toss shots. Reviewed all the big stuff... went through everything but it kept getting worst. Eventually, I gave up, tore the rifle down to put on a new barrel.... guess what? Loose scope base screw. Checked everything but didn't want to take the rifle really apart so missed the loose base screw.

Fixed that and the rifle miraculously shot as before with zero issues.

If it is an optics related problem, the best is to take off what you don't trust and put on something you or someone you know does. It would be great if a scope simply blew up.. real easy to diagnose. Unfortunately, many times it is a part or spring that moves a little here and there. The problem is inconsistent and pretty much drives you nuts.

If the parallax adjustment has suddenly changed function, that is a pretty good reason to suspect the scope. But check all the obvious stuff on the metal bits and loading too.

If using light alloy rings, maybe those once tight screws have stretched the alum and now are kind of loose? All sorts of little things that can lead to hair pulling problems.

Check anything that can go loose. Then swap in anything you can't check with something you know works. Review all your loading steps..... maybe cases are now too long (yes, that has happened to me more often then I care to admit). Maybe necks have become too thick?

Maybe your seater has gone out of adjustment and now is seating longer then you did before?

Maybe your scale has some drift or reading error?

Just go through everything and bring back to your baseline... remember those notes you took of everything when life was good?

If that barrel has lots and lots of wear, maybe the barrel is simply toast but it sounds like this is a new project so things aren't likely to wear enough to be this bad.

But if EVERYTHING checks out and you still have irratic issues, check the bedding, length of action bolts when installed.. correct as necessary THEN retune your loads.

Loads will change through the life of a barrel.

Jerry
 
I know this is highly unlikely BUT a month or so ago my rebarreled remington in 6x47 lapua started grouping pretty bad. I thought the scope was the problem BUT I thought, I am going to give the barrel a really really good cleaning just in case it has a build up.I scrubbed the hell out of it. Long story short the first 5 shot group after cleaning was right around the 0.2 mark.
 
Canuck525 said:
I know this is highly unlikely BUT a month or so ago my rebarreled remington in 6x47 lapua started grouping pretty bad. I thought the scope was the problem BUT I thought, I am going to give the barrel a really really good cleaning just in case it has a build up.I scrubbed the hell out of it. Long story short the first 5 shot group after cleaning was right around the 0.2 mark.
Click to expand...

yeah!! I learned about that...I was getting 2 inch groups for a while...good cleaning with sweet 762 and a lot of scrubbig gave me that small group next to the dime!
 
Thanks a lot Jerry and others for taking the time to answer. I have a friend who may lend me a nightforce or Viper scope and rings to test...The rings are trijicon but are aluminium. A lot of vertical could indicate a faulty scope right? I guess I'll see soon enough. it was the plan from get go to eventually change the barrel anyways though. I going to take everything apart and put it back together before I shoot it again for sure.
 
Last edited:
A couple of observations.
42gr of Varget in Lapua brass with BR-2 primers seems like a very soft shooting load. Maybe it's because of your 0.004" off the lands.

My best loads are at 0.020" off the lands.
175gr SMK 44.1gr Varget, Lapua brass, FGMM primers. Replacing the primers with BR-2 opens up the groups substantially.
180gr SMK 42.3gr Varget, Lapua brass, BR-2 primers.

The 175gr load shoots well in both the 10TR and the 10BA.
The 180gr load gets jammed into the rifling of the 10TR so I don't use it in that rifle but is 0.020" off the lands in the 10BA.
2901911D-FCBA-448F-BE10-50F2FE812FB9_zpsh8fqwoq3.jpg

This is what the 175gr load looks like being shot out of the 10BA.
I pulled a shot in groups 1 and 3.
 
Last edited:
thump_rrr said:
A couple of observations.
42gr of Varget in Lapua brass with BR-2 primers seems like a very soft shooting load. Maybe it's because of your 0.004" off the lands.

My best loads are at 0.020" off the lands.
175gr SMK 44.1gr Varget, Lapua brass, FGMM primers. Replacing the primers with BR-2 opens up the groups substantially.
180gr SMK 42.3gr Varget, Lapua brass, BR-2 primers.

The 175gr load shoots well in both the 10TR and the 10BA.
The 180gr load gets jammed into the rifling of the 10TR so I don't use it in that rifle but is 0.020" off the lands in the 10BA.
2901911D-FCBA-448F-BE10-50F2FE812FB9_zpsh8fqwoq3.jpg

This is what the 175gr load looks like being shot out of the 10BA.
I pulled a shot in groups 1 and 3.
Click to expand...

Typo...4064 not varget, I used 44 grains of varget when testing it with 168's. I edited my original post. seems like the consensus is back the bullet from the lands...

I disassembled the whole rifle, it seems like the mark on the stock from the recoil log is uneven, it shows on the left side not on the right. Not sure how much this is significant...but it is there. The previous stock was bedded behind the lug.
 
Last edited:
ALMAR said:
Typo...4064 not varget, I used 44 grains of varget when testing it with 168's. I edited my original post. seems like the consensus is back the bullet from the lands...

I disassembled the whole rifle, it seems like the mark on the stock from the recoil log is uneven, it shows on the left side not on the right. Not sure how much this is significant...but it is there. The previous stock was bedded behind the lug.
Click to expand...
That makes more sense. I'm at 41.7gr of 4064.
 
ALMAR said:
Typo...4064 not varget, I used 44 grains of varget when testing it with 168's. I edited my original post. seems like the consensus is back the bullet from the lands...

I disassembled the whole rifle, it seems like the mark on the stock from the recoil log is uneven, it shows on the left side not on the right. Not sure how much this is significant...but it is there. The previous stock was bedded behind the lug.
Click to expand...

Make some cuts in the face of the recoil lug area of the chassis to create mechanical lock and bed it using Devcon ect.
 
ALMAR said:
Thanks a lot Jerry and others for taking the time to answer. I have a friend who may lend me a nightforce or Viper scope and rings to test...The rings are trijicon but are aluminium. A lot of vertical could indicate a faulty scope right? I guess I'll see soon enough. it was the plan from get go to eventually change the barrel anyways though. I going to take everything apart and put it back together before I shoot it again for sure.
Click to expand...

Vertical can come from a number of places including rests/bench, poor load for the barrel, poor case prep, poor bedding, scope/base/rings and of course shooter. Essentially, anywhere.

Jerry
 
Get some feeler guages and check it may also shift when tightening your action screws then shift further once tou fire the rifle. It could be torquing to one side and is more of a case of out of spec tolerances on the action. Bolt your barreled action in and check the recoil lug area with feeler guages. You can use bluing die ect to show how the lug is seating once 5he action screws are tight. From there you can trace what is out of spec on the action bolt holes, face of action ect.
 
Mystic Precision said:
Vertical can come from a number of places including rests/bench, poor load for the barrel, poor case prep, poor bedding, scope/base/rings and of course shooter. Essentially, anywhere.

Jerry
Click to expand...

There has been a lot of good information in this thread. So what causes horizontal stringing? I've been dealing with this in a rifle that didn't always do this.
 
Chuck said:
There has been a lot of good information in this thread. So what causes horizontal stringing? I've been dealing with this in a rifle that didn't always do this.
Click to expand...

Besides the obvious answer of wind, there are a couple of things. One theory is that adjusting seating depth results in changing horizontal spread. I don't buy it myself, the barrel oscillates in a circular motion, not left to right.

IMHO, it is shooter induced, not mechanical. Personally, I see horizontal patterning from changing shoulder-buttstock alignment/butt pressure. The recoil from each shot pushes your shoulder back and unless I return to the same position, I find I'll throw a shot to the right. Try using a quality front rest or ski bipod and rear bag and focusing on positioning.
 
Chuck said:
There has been a lot of good information in this thread. So what causes horizontal stringing? I've been dealing with this in a rifle that didn't always do this.
Click to expand...

Imagine the barrel is oscillating during the firing cycle. Somewhere in this wiggle, the bullet exits the bore and heads for the paper.

The more the ammo and barrel are out of tune, the farther the bullet is sent from desired POI. This dispersion will have both a horizontal as well as vertical component.

Large groups ie spray and pray are a prime example of too much of both

When the ammo/bullet and barrel approaches being in tune, the oscillation as shown by the target will shrink. With careful loading and good barrels and shooter, you can tune to a point where the main error in dispersion is more vertical or more horizontal.

Assuming wind and/or mirage is not affecting your aim and you have good shooting tech, a larger then expected group simply means the ammo and barrel are not a good fit. Small changes on powder charge will show dramatic changes in group size AND shape.

See my articles on my website to help with load tuning. You need a very good scale and good loading techniques to get the powder charge precise enough to see this on a consistent basis. Of course, you have to be able to shoot consistent/well enough to not induce more "noise" into your groups.

Jerry
 
This is pretty much what I was going to say.

smoothbore75 said:
All sound advice, & if I read correctly above it worked.
Only thing I'll add is a general suggestion to anyone facing probs like this in the future: treat it like a science experiment. I don't mean nuking your ammo to see how long it takes to go off (that's just for cats), rather; out of all the good suggestions above: make sure you only change one variable at a time between repeated tests/experiments.
You change 3-4 variables at once & you may easily fix the problem, but without ever figuring out exactly which one it was?
Worst-case scenario if you only swap one variable at a time: you have to fire more tests...boo-hoo?
Click to expand...
 
You must log in or register to reply here.
Back
Top Bottom