I was at the range the other day working on a load for my son's .243 win. The one five shot group shot within a 1" square, but what concerned me was the first shot was at the bottom left, and last last shot was in the top right in almost a perfect diagnal line with each shot creeping from the bottom left to the top right. The load was 44 gr of reloader 17 with 85 gr Barnes TSX bullets.
What would be the cause of this, and is this a possible problem with the load or gun?
Thx for the info. It was warmer than I like to shoot at but the hunting season is getting closer for us, and I need the load done. The gun that I am shooting is a Savage youth model in a .243 win, whcih is certainly not an expensive gun. The barrel was warm, but not smokin hot, and I did allow a bit of time for the barrel to cool.
Would you suggest that I go back to the range and shoot the same powder combinations, and allow a few minutes between rounds to see how this affect the group?
First, check the action screws, scope mount and the ring screws for tightness. Do not overtighten them. Is the scope of good quality? Next, slide a dollar bill between the barrel and stock. Any binding? If so, I bet that is your problem. Rasp out the high spots until they do not touch. You can wrap sandpaper around an old flashlight battery to do this. Clean the bore thoroughly.
How is your bench set up? Are you using solid front and rear rests? The barrel should never touch a sand bag. Hold the rifle the same every shot. Same technique each shot. Five shots should not overheat any barrel. For load testing, I often fire 10 shots in ten minutes before allowing my barrel to cool somewhat. But remember that first shot from a cold barrel is the one you need to hit dead on.
I totally agree here, don't bother wasting time/money traveling back & forth the range until you know for sure the barrel is properly floated & the action, base & ring screws are properly secured (torqued if you have the tools).
I just had a new scope put on the gun on Friday a Bushnell Elite 3200 5 x 15 x 40. I did check the float with a dollar bill more than once, and the float is good. I will check the action screws to see if they are tight, and then go back to the range to see what happens.