Load Development

S

smoothie25

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I shot a ladder Test and found 57 grains of h4350 with a 180 AB to be in a node. I shot two separate three shot groups at ~100 yards. They both produced near identical patterns. Two touching and one flyer about an inch away. All the shots felt good, no pulled shots. I'm puzzled as to why this happened twice. Thoughts?
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This sometimes is the result of the pressure that a shooter places on the rifle. At 100 yards any changes in velocity would have considerably less effect on the group size. It might show that the barrel has stress in it and the point of impact changes as the barrel heats up too. If you fired more than three shots it would be easier to give a reliable answer.

When I am working up a load or testing the repeatability of a load I use four five shot groups with one target placed on the stand and a new target placed over it. That gives me four five shot groups and a target with an aggregate of all twenty rounds. It provides a lot more information than any of the five shot targets can alone.
 
What were the two charges?

A proper ladder test is conducted at a minimum of 300 yards, then round 2 is conducted at least 400 yards etc...

At 100 yards you should be conducting an OCW test developed by Dan Newberry. You will want to Google that.

I hope that makes sense. Usually a 5 shot group doing it round Robin will give you what the load is doing on a cold bore, warm and hot bore

My wife thinks I only have 3 guns
 
It happened twice merely by chance.
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No not necessarily . I was holding off on this until the OP answered a few questions but I'll explain how there could be an equipment issue outside of the shooter or load .

Here are a few photos of targets I shot a few years ago .
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This was a 4 shot group shot consecutively . As you can see there seems to be two separate groups yet they were shot all with in 2 min ( about 30sec apart ) . If I had only shot 3 rounds that group would look just like the OP's targets .

I keep all my load development targets for future reference and I can say I have a large group/lot of targets that look similar to the one above that were all shot during the same 6 month period . The reason I have a large amount of these is because I did not see the trend for quite some time and the reason for that is not all my groups looked like that . Some were a little less obvious like this one

3xkz.jpg


How ever one day I was shooting some confirmation groups . I do this when I think I have a good load . I load 20 rounds and shoot two 10 shot groups through my chrono . What I saw next blew my mind .

10 shot group shot in 30sec intervals -ish
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:eek: How the heck could I have just shot two separate sub moa groups in the same string with the exact same POA for every shot ? This caused me to go back and look at all my old targets and sure enough there was a trend/pattern of these groups .

At first I thought it was my parallax adjustment was all screwed up but then thought "I'm not THAT good a shooter to be able to get behind my rifle consistently two separate ways in the same string . So I went to the internet and asked around . Not sure which forum helped me out but think it was here .

Anyone want to guess what the problem turned out to be ?? I'll wait to post what was wrong to allow for some guesses ;)
You know it was not parallax . Maybe this will help , It had nothing to do with the scope or mounts .
 
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The charges were both 57gr. I dont know what shot the flyer was for the first group but the flyer was the first shot for the 2nd group.

I did the ladder Test at 300 yards then shot these groups at a little over 100.

Metal, that's interesting. What did you come up with as the cause?


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Well I was really hoping some of you would have tried to guess how I got those double groups .

Since nobody wants to play :(. I'll just say loose action screws and leave it at that . :o
 
I checked my action screws and they were good. My scope ring screws weren't as tight as I usually tighten them to. Could this be the cause? Seems weird that I was able to get repeatable results with two touching and one flyer.


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Loaded up some ABs today with a shorter overall length. The pic in my first post was at 2.61" CBTO. I loaded 4 each of 2.60", 2.59", and 2.58" and shot at 100 yards.

2.60" shot a little over and inch. 2.59 shot under an inch. 2.58 opened back up at 1.3ish inches. I loaded 8 rounds of 2.59 to confirm my initial results and shot two separate groups. They shot .82 and .96 inches. I'm pretty happy with these results! Going to shoot further out next trip to see if they stay together.

Metal god, what was the cause?


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metal God

Well I was really hoping some of you would have tried to guess how I got those double groups .

Since nobody wants to play . I'll just say loose action screws and leave it at that
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Honestly I would have said a loose scope before you answered... Either bases or ring screws. Had the same thing happen to me in a .270 once I was helping a friend sight in. I would shoot a group, adjust the windage and elevation, the shoot another and it would still be off. Turned out the base was not tight. He now uses lock tight on his bases.

As per the OP question, There are so many reasons for flyers that it's hard to pin them down.

If the POI isn't moving, then it's not the rings, base, action screws etc... Because when that happens, the poi changes like metal gods pics.

It could be heat related, but that's easy to test, just let the barrel cool all they way down between shots with 3x5 shot groups, then fire 3x5 shot groups letting the barrel get warm enough you can still touch it but it's uncomfortable.

You could be making a mistake making the loads, not letting a digital scale settle and having different charge weights. Or if these have been fired a few times, perhaps you are double or triple stroking your press when resizing on some cases causing differences in bullet hold. Bullet hold can change velocity by 50fps or more in some instances. Do you have a chronograph? If they were all shot over a chronograph you could see if the flyers were different velocities. That would indicate a reloading mistake.

Then there is the shooter himself. I can call fliers as I shoot both eyes open and watch my target and sights closley plus I can feel it.

But if we assume that you arnt flinching shots, and there isn't anything thing mechanical going on, a chronograph would help diagnose the issue.

Then, if it isn't a velocity issue, perhaps you have some bad bullet run-out when seating. Run-out can cause a 5 or even ten thousandths difference in CBTO. That's enough to change your poi an MOA or more.
 
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Metal God answered it was action screws.

Sometimes its the barrel and how it reacts to loads.

I have a pencil 270 that puts on 1.5 inch or so to the left and then two touching.


As it is warming up, outside these days I will be running a series of loads to see if it can be cured with the right load and or COAL.

More a challenge than anything. I have yet to get a 270 to shoot good (my definition, at least MOA)
 
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