Weird load with my 30-06

S

Six Pack

New member
I found a load that my Model 70 Extreme Weather seems to really like: 61g of Hunter in Lapua cases, with CCI BR2 primers under a 165 Nosler Balistic Tip about 30 off the lands.

The weird part is that it shoots 5 shots in a perfect horizontal string about 3 fingers wide...every time. All holes touching on a horizontal axis. I chronographed the load and it shows 2840fps with a SD less than 2..... EVERY TIME.

Anybody have any ideas about how to tighten it up and bring all holes under an inch???
 
If the holes print adjacent to each other in the string, the barrel heating up and walking is the issue. The why may be harder to pin down. Contact with the barrel is one possibility, but the need to blueprint the receiver or stress-relieve the barrel are others.
 
The barrel is free floated from the factory and I wait about 5 minutes between each shot. The shots are printing, all touching or VERY close, across a 9 to 3 o'clock plane. I am amazed too at the lack of SD. I've probably put 20 rounds across my MagnetoSpeed and it has not exceeded 2 yet. I have been thinking it might be seating depth which I have not changed.
 
Are you pulling rifle into your shoulder when you shoot?
Are you sure you are getting consistent shooting position after waiting 5 minutes between shots?
Any possibility the scope/ sight picture is canting?
 
To answer a few questions above and add a few details.....

I'm a 66 year old hunter. I've been shooting for about 60 years and hand loading for over 40. I currently load and shoot 15 plus rifles and go through at least 1000-2000 rounds per year. This 30-06 is the only rifle that prints in a horizontal group and it only does it with the one load...61g of Ramshot Hunter. The rifle also seems to like 57.5g of H4350 and prints clovers of an inch or slightly less with that load.

What makes me think there is something special about the Hunter load in question is the amazing SD of 2 or less and consistent velocity. I have not personally experienced any load that tight before, but I have read many times the most consistent load will produce the best accuracy.

Also, regarding my targets and rest, I use a standard 100 yard bullseye but draw a cross with a permanent marker from 12 to 6 and 9 to 3 with a ruler across the bullseye to make sure I am holding consistently on every shot. The rifle is also on rests, front and rear, and I make sure the rifle is contacted on the same spots with every shot.
 
Hmmm. That is is interesting. Again, do they print sequentially adjacent to one another, like the shift increases with each shot, or do you get some non-touching shots that later fill in as you complete the string?

I know some match shooters have found it can take up to a dozen shots for powder fouling changes to settle out. Perhaps this particular powder needs more fouling shots?

Does it do this both with and without the Magnetospeed attached? I am wondering if it could be shifting slightly.

If we assume the cause is the phase of a cyclical horizontal recoil moment, it should change phase with barrel time and you want barrel time to cause the bullet exit with it at one extreme or the other, but not during its fastest rate of change. Try dropping the charge weight 15% and working back to matching velocity or a minimum group point with the bullet jammed 0.010" into the lands. Try working it back up at 0.020" and 0.040" and 0.060" and maybe even 0.080" off the lands, as well, and see if you can make it better or worse or find a null or find a trend towards one.
 
You might try moving the COAL in .010 and .015 and see what results. Same with moving further out.

I don't have Hunter Load data for that bullet, not sure what pressure you might hit if you get too close in so serious caution there.

There was a comment from the Houston Warehouse saga that he could tune the pattern doing so.
 
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