Why does my M1 make two groups like this?

The 3 shots on the paper, plus the 3 just off are all from the same string of fire. 100 yds, just testing a load. However, it does this with other ammo as well. In fact, in the last C&R match I shot, I had wider spreads, but the same general pattern. I didn't/haven't watched closely enough to see if it alternates according to which side of the clip the round feeds from, though it wouldn't surprise me if it was that. The question is: Why does it do this, and how do I get it to put them all into 1 group?

https://www.milsurps.com/images/impo...528148ed-1.jpg

Sorry if my image host has rotated this img 90 degrees left. I can't seem to get it to show it straight.

The reason you'll have a split group is because you've changed your position or an elbow shift. It has nothing to do with the ammo, clip feed or rifle. A vertical group is breathing, lateral spread is elbows moving. Two separate groups, if one of these is above the other is a different point of aim. That could easily mean the foresight tip not centralized in the aperture. I take it this was rested and on a bench?

The way to overcome this is careful practice...perhaps a coach while you shoot.

This was laying across a bag (not a sandbag, my range bag) out in the desert. The C&R matches are slung up (of course). While I do not say that this is not an aiming or position issue, it's almost ludicrously repeatable/repeated. I wonder what I could be doing so very precisely and repeatably, but in two different ways...?

I lay on firing points beside recruits for decades and watched this sort of this incessantly.

BAR may not be far off. For what it's worth I find targets where my POA is on a square or edge versus a circle are harder to center on at distance.

To be clear, when you shot the string of six did you shoot three, reload, shoot three? Shoot one at a time, checking your scope each time? Shoot six in a row without moving up off the gun? Did you have a spotter calling each shot? This can help narrow down what is happening.

No, this was one en bloc clip. The first two I was aiming elsewhere, until I found about where POI was vs. POA (this was load development with Lapua's 185-grain D-46 over AA4350, whereas I normally use lighter bullets and AA4064 in this gun). Once I found it, I moved to a new POA and fired the remaining 6 rounds in the clip, and those 6 holes are what I got. I don't have a spotting scope so I can't say for sure with just my eyes that it was one-then-the-other alternation.

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Originally Posted by cipherk98

BAR may not be far off

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Gee, thanks.

You'd be surprised what an educated coach would see when watching you. There are so many variables here, without me actually being there how can we actually say? I didn't examine the rifle pre firing, I didn't watch you while reloading, I didn't test and adjust your firing position...I didn't watch you shoot the group. But I have a good idea...

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Originally Posted by MZ5

No, this was one en bloc clip. The first two I was aiming elsewhere, until I found about where POI was vs. POA (this was load development with Lapua's 185-grain D-46 over AA4350, whereas I normally use lighter bullets and AA4064 in this gun). Once I found it, I moved to a new POA and fired the remaining 6 rounds in the clip, and those 6 holes are what I got. I don't have a spotting scope so I can't say for sure with just my eyes that it was one-then-the-other alternation.

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Next time see if someone with a scope might be willing to spot for you or see if anyone you know can go with you. For me personally, going left to right or up to down on each shot is due to my POA wandering, typically if I shoot a string then reload and shoot another to find them going somewhere else it's because I moved when I settled back down.

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Originally Posted by browningautorifle

Gee, thanks.

You'd be surprised what an educated coach would see when watching you. There are so many variables here, without me actually being there how can we actually say? I didn't examine the rifle pre firing, I didn't watch you while reloading, I didn't test and adjust your firing position...I didn't watch you shoot the group. But I have a good idea...

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The shots you knew you missed the moment you pulled the trigger are easy. The subtle ones are a real pain. Like when you're mid string and drop 4 or 5 shots for no reason then magically pick it back up. What you're talking about bites me the most when shooting the sitting rapid stage... seems like I can never get into the same position I was in when I took my sighters. Coincidentally it's also why I changed how I now test handloads - used to shoot one at a time and check each time on the scope. Now I shoot one for POA/pressure signs, load 5/8/10/whatever and shoot without looking up again.

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Originally Posted by cipherk98

What you're talking about bites me the most when shooting the sitting rapid stage

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That's another thing many can't grasp, the four positions have four different MPI and you have to be aware.

I guess I have a lot to learn still...................

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Originally Posted by Steve762

In future watch that the gear bag is under the butt stock and not the front hand guard. Rifle may have worked it's way back on the gear bag during the string (recoil) so that the rifle was being supported in front of the sling swivel. That can cause groups to change POI.

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That's very useful; thank you. The rifle was definitely supported in part under the handguard. It's a large gear/range bag, so it was all along under the main stock and the handguard.

is your front gas cylinder tight on the splines?
you need to at least make sure your tracking your shots precisely

are you 100 % sure each 3 shots in the two groups where shot consecutively ?

No, I thought I already said (maybe I didn't) that I cannot be positive that the hits alternated according to which side of the clip the cartridge fed from. The gas cylinder is tight on the splines, but the plug cannot screw in tight without putting a bend/bind in things.

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Originally Posted by MZ5

No, I thought I already said (maybe I didn't) that I cannot be positive that the hits alternated according to which side of the clip the cartridge fed from. The gas cylinder is tight on the splines, but the plug cannot screw in tight without putting a bend/bind in things.

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Bend and bind? That does not sound good.
Try this draw some 4 3" bulls on a large piece of paper.
Take 2 shots at each bull and see how your groups look vs point of aim.
I have a M1 that has a cork screw pattern to its shots. You can compare shot for shot and it's the same patern.
It's the most correct WWII SA I have so I have not messed with it.
The M1s can be frustrating.
Although remember in the accuracy and testing portion of the weapons command over hall manual
They have you fire 3 warming shots before shooting the 5 consecutive shots for group testing at 1000" inches and that group is good to go at 1.77" or less.
All my M1s like to toss the first cold shot especially with HXP. It's not as bad with my reloads. My current M1 i use in the JCG as issued match will always shoot low right on first shot then settle in and drift a bit high as it gets hot. Not much but enough to loose a few into the 9 ring if I don't pay attention or cant see my impacts.

You are probably seeing the outside edges of a really big group, you are stopping too soon put 5 or 10 more shots into it and see what develops.

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Originally Posted by MZ5

The 3 shots on the paper, plus the 3 just off are all from the same string of fire. 100 yds, just testing a load. However, it does this with other ammo as well. In fact, in the last C&R match I shot, I had wider spreads, but the same general pattern. I didn't/haven't watched closely enough to see if it alternates according to which side of the clip the round feeds from, though it wouldn't surprise me if it was that. The question is: Why does it do this, and how do I get it to put them all into 1 group?

https://www.milsurps.com/images/impo...528148ed-1.jpg

Sorry if my image host has rotated this img 90 degrees left. I can't seem to get it to show it straight.

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So I'm looking at your group again where's the 8th shot?
Also your groups are what 1" apart. So your looking at a sub 3moa rifle. Not to shabby.
I say try shooting prone with a sling and support your arm on a nice solid sand bag. If possible get into position find your natural point of aim and have someone push and pack the bag under your slung support arm. Shoot 20 rounds like you would in slow fire course. See how things look. If your in the 10 ring or better, shoot more.