Mind wandering.....

C

cdoc42

New member
I was working up loads for my 6.5 Creedmoor and .25-06 and at the very end of the session, the last 5 shots I fired with the .25-06 delivered a 4-shot bullseye group that measured 0.5 inches. I had pulled the 4th shot on purpose because I thought I may have missed the target with 2 of the previous 3. When it landed outside of the bull at 5 o’clock, I put the fifth shot into the same hole as the other 3.

This morning I woke up and my mind wandered into this scenario above, and I suggested to myself that I would probably not be able to duplicate this again because my shooting history generally finds great groups are difficult to duplicate for a variety of reasons.

I learned from the benchrest guys that the vertical rod on the rifle rest should be the stop you use every time when placing the rifle on the rest so the muzzle is exactly the same distance from the target each time. In addition, if I use a rest that jumps back from recoil, I mark the table where the rest legs touch so I can return the rest to the same location as well.

But I NEVER considered initially putting the rest itself in exactly the same location on the table with each shooting session. So it makes sense to me if the rest jumps back two inches and that changes the bullet trajectory, so would the trajectory change from session to session if I start with a rest that is two inches (or more) from the same place it was at the last session.

Should I go back to bed or simply search for my T-shirt that says “Let me overthink this!”?
 
I suspect that you would get greater variation from minor adjustments to your set up position caused by recoil or moving your eye in relation to the eyepiece than from two inches difference in barrel position relative to the target.

In my experience, two inches of set back in your set up position would actually change your set up considerably - enough to change the POI.
 
I think Rimfire5 has it right. The importance of locating the rest in the same place each time is likely helping control the shooter's position first and foremost. The one possible exception that comes to mind is if your bench is rickety or uneven enough, some spots on it may introduce new recoil moments by failing to give uniform support to your rest feet. That could introduce variations in how the muzzle moves around during recoil. Hard as it is on unpadded elbows, there is a lot to be said for properly leveled concrete.

I once was shooting a 100-yard cloverleaf with my 222 Rem, when I got an unexplained flyer about two inches out at 2:30. Figuring the scope mount or the scope internals must have shot loose, I intentionally aimed at the flyer and shot again to see if the same amount of error appeared at 2:30 from that hole. Instead, I got no new hole at all. I was dismayed, of course, as my accurate little Remington 600 rig seemed to be failing me. So I stopped firing and went up to the target and found the flyer hole had the fine black imprint lines of 6 fly legs around it.
 
The bench I use most often is painted 2 x 6's for the table, bolted to telephone poles sunk (I don't know how deep) into hard-as-a-rock dirt. The whole shebang is under roof, never gets wet. I shot that .25-06 again to duplicate the 4-shot hole but another variable entered the process - a pounding rainstorm. I did get a group good enough to have taken a deer; all were within a 3-inch circle and I just imagined that bullet pushing water out of the way on its path.
 
the vertical rod on the rifle rest should be the stop you use every time when placing the rifle on the rest so the muzzle is exactly the same distance from the target each time.
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Placing the same spot on the rifle on the rest eliminates several variables, but distance to the target is not one of them. When you fire a rifle, it has recoil, harmonics, and balance characteristics. Placing the rifle on the rest in the same place each time eliminates the variability. Similarly, consistently shouldering the rifle will also have an effect on accuracy.

You can try moving the rest forward and backwards to see its effect on group size, but once you settle on a given position for the rest always use that spot.
 
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