grouping question

[gohring3006]

I tried some new loads today 200gr.smk 52gr. Imr 4350 coal 3.34in 30/06 I can get two touching and one shot about .75in away from the two touching at 100 is it seating depth, the primers or the brass the brass is basically range brass I keep federal with federal, rem with rem etc.but its consistent with every brand of brass just wondering if anybody has any suggestions...

 

[jpd676]

Well,

It may not be any of those issues. I had a rifle that did something similar. It had a thin barrel and by the third round the barrel was heating up and any rounds after that would walk up on the target.

I also had a scope with poor eye relief and I always got two rounds touching and one around an inch left and slightly low. I tried everything and it did the same, until I switched the scope and then the problem went away.

 

[gohring3006]

Well,

It may not be any of those issues. I had a rifle that did something similar. It had a thin barrel and by the third round the barrel was heating up and any rounds after that would walk up on the target.

I also had a scope with poor eye relief and I always got two rounds touching and one around an inch left and slightly low. I tried everything and it did the same, until I switched the scope and then the problem went away.

well I those two problems its a sporter barrel and a short eye relief scope thanks for your reply its just frustrating to get two basically in the same hole then one off I was suspicious of the thin barrel but never thought of the scope.....

 

[Timber338]

There are so many different things that could cause this. I think the positive is that your gun has the potential to shoot two that touch. The hard part might be finding what's causing one to fly.

Assuming that there is nothing wrong with the rifle....

Have you done enough load development to know that your loads are in the middle of a sweet spot? if you are on the edge of a sweet spot, two of your shots might come out at about the same velocity/pressure and touch. The other shot might be outside of your rifles sweet spot velocity/pressure and have a different point of impact. One thing that comes to mind is your brass might be the same brand, but the neck tension could vary quite a bit. Have you sorted your same-brand brass by weight? Even if it's the same brand, if they are not sorted by weight you can get a big enough variation in case volume that it might cause your problem. Maybe chronograph your loads and see if there is any correlation between point of impact and velocity.

 

[gohring3006]

There are so many different things that could cause this. I think the positive is that your gun has the potential to shoot two that touch. The hard part might be finding what's causing one to fly.

Assuming that there is nothing wrong with the rifle....

Have you done enough load development to know that your loads are in the middle of a sweet spot? if you are on the edge of a sweet spot, two of your shots might come out at about the same velocity/pressure and touch. The other shot might be outside of your rifles sweet spot velocity/pressure and have a different point of impact. One thing that comes to mind is your brass might be the same brand, but the neck tension could vary quite a bit. Have you sorted your same-brand brass by weight? Even if it's the same brand, if they are not sorted by weight you can get a big enough variation in case volume that it might cause your problem. Maybe chronograph your loads and see if there is any correlation between point of impact and velocity.

thanks for the input im going to sort my brass like you said and do the chrony test....

 

[Timber338]

thanks for the input im going to sort my brass like you said and do the chrony test....

It can be very hard to find the exact problem, but with enough patience you can usually figure it out. Try and be as scientific as possible to eliminate variables (or sources of error) one at a time. Comparing velocity to point of impact is a great start and is easy. If you find that the flyer is always lower in velocity by maybe 30fps than the other 2 shots, then increasing about a 1/2 grain should get the velocity of all your rounds up a bit higher without bumping you out of your sweet spot on the high end.

If you find that there is no correlation to velocity and point of impact with your particular load, then the next step I would turn to is seating depth adjustments.

 

[gohring3006]

It can be very hard to find the exact problem, but with enough patience you can usually figure it out. Try and be as scientific as possible to eliminate variables (or sources of error) one at a time. Comparing velocity to point of impact is a great start and is easy. If you find that the flyer is always lower in velocity by maybe 30fps than the other 2 shots, then increasing about a 1/2 grain should get the velocity of all your rounds up a bit higher without bumping you out of your sweet spot on the high end.

If you find that there is no correlation to velocity and point of impact with your particular load, then the next step I would turn to is seating depth adjustments.

thanks again. The good thing is that I think I'm close to the sweet spot im going to get a chrony and start there im a little suspicious of the fed. Mag. Primers (215s) so I might try a load with standard primers just to check