What caused this 600 yard group? It had the possibility of a new record . PIC

[Steve Wilson]

This is almost perfectly symmetrical; something had to cause it, but I don't know what. I don't remember which way the wind was blowing then or have any idea the order in which the bullets hit the target. Wind from the left; bullets go right and down. From the right; they go left and up. I know that much, but there wasn't enough wind to cause this much vertical dispersion, over such a short horizontal.

Which ever way it was going, I didn't change my point of aim from the sighter target. This is from one of my last two targets in Heavy Gun, I shot the same rifle in Light Gun. Somewhere near the end of Heavy Gun I noticed that when I lightly put my shoulder against the butt, that the point of aim changed ever so slightly and I corrected it with the joystick on my Farley rest. I was wearing a light Carhartt hooded jacket and a fleece insulated top, under my shirt.

I'm thinking it was because of how the extra padding was causing the stock to shift as it hung up on my shoulder as I was settling into the rifle. Once I noticed it happening, I backed off and moved my shoulder until it didn't move the target dot. Or, didn't seem that it moved, to me. But it's extremely difficult to see that small amount of movement at 600 yards with a 36 power scope and the given mirage at the time.

Like I said earlier, it is almost perfectly symmetrical. Any ideas of what caused it? If only those two outside bullets would have landed with the other three. :'( The group was officially measured at 2.722. I measured the three in the center at .3085.

6 Dasher
105 Hybrids sorted to .1 grain, untrimmed or repointed
32.5 grains Varget
205M primer

 

[SHall]

Steve,
I see you have been working hard at load development, that is what it takes! A group dispersion like that can be caused by several things. The first thing I would have done is to look at other peoples targets on that relay and see if they were similar. If they were, it could be wind. It does not take much of a switch, ant St. Louis is famous for that! Second cause is you are slightly out of tune. I have seen unexplained verticle when tuning loads like your target. Three, you could have been getting uneven shoulder pressure between shots. Four, and you may know this also. The benches at St. Louis have a slight "give" or movement to them if you lean at all on them. The post are bedded in epoxy or something that allows them them to move slightly if pressure is applied to them. Unfortuanately, there never seems to be one concrete answer until you rule everthing else out! Samuel Hall

 

[normmatzen]

You realize, of course, that group may net you a ribbon at an NBRSA club match!

Have you considered the cause is pure dumb luck?

 

[necchi]

It's nothing more complicated then;


"That's the name of the game Pal" ;D

 

[dkhunt14]

Did you make sure the parallax was out of the scope?

 

[MarkS]

Steve,

It take nothing to move a bullet 1" at 600 yds. I have shot many 4 in and 1 out. I shot a 2" group at Oak Ridge. TN, when they shot 600 BR. 4 shot around 0.75" and out. The pit crew said it was my 3rd shot. I also had one at Peidmont with 4 about 0.300" 5 made it 1.3". Finely I put a 0.749" together LG record in 2007".

Don't worry what caused it, if your gun will put 3 in 0.3", it will put them it there sooner or later. You can drive yourself crazy trying to find something thing, that is not There. This can be cause by the slightest touch in gun handling. How did the gun shoot on the other targets?

Mark Schronce

 

[Hombre0321]

Steve, I also am a long range Benchrest Shooter so I feel your pain. However nothing wrong with a 2" group, but I understand you are seeing the "Only If".

You mention the mirage was bad that day, that easily could be the cause right there, mirage can eat your lunch some days.

And remember Steve thats why we shoot 5 shoots and not three. Good shooting anyway and keep plugging......

Roland

 

[jhord]

Too bad it's not best 3 out of 5 huh? ;D That's still some good shooting no matter what.

A friend visited me last week to talk about getting started in benchrest shooting. He talked about all his load development, how good his 3 shot groups had been, so on and so forth. I didn't say it but I was thinking, "just wait until you have to shoot 5 shots for group buddy, those awesome groups won't be so awesome." :'(

 

[Steve Wilson]

Yea, it was probably mirage, wind, uneven pressure on the buttstock. Like you guys say, it could be for any number of reasons. The only thing to do is just keep plugging away at it.

Thanks for the suggestions,

 

[johara1]

From where you have the group located i would say there was a pick up or a let off and you gave the relay weather report. We all do it, so don't worry about it. I had 5 shots under .600 at 1K to bad it was a 10 shot match.......jim

 

[4xforfun]

I have a world record group going EVERY time I shoot. It's just those dam 2nd through 5th shots that always seem to screw everything up!!

 

[Steve Wilson]

Jim and 4X, isn't that the truth? :

I am sometimes tempted to do 3 shot groups for load development, but too often will send that fourth or fifth one flying. Three or four in one teeny little hole then KABAMY.

My 28 year old nephew started shooting with me this year; his first ever experience with centerfire rifles. We built a precision 6.5x284 hunting rifle and I took him to the range. He really was doing remarkably well for shooting off a bench for the first time. Then I gave him a few bench shooting tips; stay consistent with everything, don't be shuffling your feet around, follow through, etc. With that, he started doing much better and was even calling out his own fliers after a bit.

Towards the end of our range session he began shooting some bug holes at 100 yards. But he would invariably send one out of the group on his fourth or fifth shot. I was laughing and told him that he just couldn't stand the pressure of looking at that one hole on his target while he shot the remainder of his 5 rounds. Welcome to the club, Scott; try to ignore that tiny hole, focus on your technique and watch the windflags.

I have to remind myself of that same advice now and then.

 

[johara1]

Once you have your gun in tune, it's the conditions. The most important thing you will learn is how to dance with the wind and the true value of a hummer barrel.......jim

 

[Josh11]

Good way to keep a new shooter from looking at the group and throwing a shot, cover up each shot with a sticky of some sort and just look at the actual target when done with the string by pealing off the stickies. I have to do this for the most part as Im still learning a lot on the range.

 

[glo]

This is almost perfectly symmetrical; something had to cause it, but I don't know what. I don't remember which way the wind was blowing then or have any idea the order in which the bullets hit the target. Wind from the left; bullets go right and down. From the right; they go left and up. I know that much, but there wasn't enough wind to cause this much vertical dispersion, over such a short horizontal.

Which ever way it was going, I didn't change my point of aim from the sighter target. This is from one of my last two targets in Heavy Gun, I shot the same rifle in Light Gun. Somewhere near the end of Heavy Gun I noticed that when I lightly put my shoulder against the butt, that the point of aim changed ever so slightly and I corrected it with the joystick on my Farley rest. I was wearing a light Carhartt hooded jacket and a fleece insulated top, under my shirt.

I'm thinking it was because of how the extra padding was causing the stock to shift as it hung up on my shoulder as I was settling into the rifle. Once I noticed it happening, I backed off and moved my shoulder until it didn't move the target dot. Or, didn't seem that it moved, to me. But it's extremely difficult to see that small amount of movement at 600 yards with a 36 power scope and the given mirage at the time.

Like I said earlier, it is almost perfectly symmetrical. Any ideas of what caused it? If only those two outside bullets would have landed with the other three. :'( The group was officially measured at 2.722. I measured the three in the center at .3085.

6 Dasher
105 Hybrids sorted to .1 grain, untrimmed or repointed
32.5 grains Varget
205M primer

Holding less then 1/2 MOA at 600 with 5 shoots... Looks like a normal group to me.