New Load Grouped Great; Not So Great Today

[General RE LEE]

I found a load for my 7STW Berger VLDH 180 H1000 that shot a .296" group at 100 yards during load development. I loaded up 25 rounds and today the groupings weren't as tight. It was hot and I was struggling to get the barrel cool with cold wet towels.

Anyone have a good load and some days they don't group? I'm thinking it was the heat and maybe I was off. Dunno

 

[C.O. Shooter]

How many rounds did you fire in a string? How many did you fire in total? All 25? If so how long did it take you to shoot?

 

[General RE LEE]

How many rounds did you fire in a string? How many did you fire in total? All 25? If so how long did it take you to shoot?

I'd shoot 5 rounds and then throw a towel pulled out of an icy cooler over the barrel and let it sit for 5-10 minutes. Maybe 2 hours? Had my boys with me and I was focused on what they were doing at their bench.

 

[adam32+P]

How much did they open up? To .5" or like 3"? What contour barrel? Same brass? Same powder lot?

I'm gonna say hot barrel and shooter error until more info is provided.

 

[Chadp82]

Been there.

Mine turned out to be an under torqued scope ring. Check the equipment (rifle/scope). Check everything.

In my case, I had a great group, then beat my head against a wall to understand why it fell apart on the next trip. After 3-4 range trips I was ready to give up. Admittedly, took me that long to figure out. I restarted load development, and a friend said check the scope mounts, stock, every screw, when I spoke to him. Torqued the screws to recommended setting, and solved the issue.

Went back to the sweet spot I found before and had the same result, but POI shifted. That may not solve your issue, but worth a check. For me, I felt dumb about it, but lesson learned.

After that, I have 1 rifle I use to prove if it's me or the equipment. It an old one but tells me if it's a bad day for me or not. I usually take it, but don't shoot it much since I don't hunt with it anymore. I have a tried and true combo. If I shoot another rifle and it seems off, I shoot a 3 round group to tell me if it's me or the other gun……. Sometimes it's a bad day, I have them. Others probably do too

 

[General RE LEE]

How much did they open up? To .5" or like 3"? What contour barrel? Same brass? Same powder lot?

I'm gonna say hot barrel and shooter error until more info is provided.

1/2" and the groups kept walking up the target. Had to adjust elevation to get it back to bulls eye. Also had some fliers.

 

[pawater]

How did your velocity compare to load development? May of jumped out of node due to barrel speeding up....or the heat. How many rounds down the pipe?

 

[Buffalobwana]

1/2" and the groups kept walking up the target. Had to adjust elevation to get it back to bulls eye. Also had some fliers.

Wait, you kept having to adjust your scope? Groups walking up? Like maybe your scope reticle was creeping down?

I'm thinking it's your scope.

 

[cactusjack]

I found these articles worth my time when trying to develop accurate loads:

Parts 1-3:

How To Predict The Future – Statistics For Shooters Part 1

I actually believe the average shooter might get more value from this Statistics for Shooters serie...

precisionrifleblog.com

Muzzle Velocity Stats – Statistics for Shooters Part 2

Consistent muzzle velocity is key for long-range shooting, otherwise, bullets that leave the muzzle...

precisionrifleblog.com

Precision & Group Size – Statistics for Shooters Part 3

This article is going to dive into the most effective ways to quantify the precision of a rifle and...

precisionrifleblog.com

 

[RockyMtnMT]

Wait, you kept having to adjust your scope? Groups walking up? Like maybe your scope reticle was creeping down?

I'm thinking it's your scope.

I agree. Sounds like something loose or scope going gunny bags. I have burnt more powder than I want to know, chasing something loose in the rifle system, thinking it was a load issue.

 

[esshup]

Something loose like what was said above, anybody think about a pencil barrel heating up and moving?

Also, maybe the OP isn't in the center of the node, because he picked the smallest group, and the group is opening up because of the different atmospheric/temperature conditions of that different day.

A friend had a .338 Win Mag that would vertically string as the barrel warmed up. He sent the barrel/action off to get cryo treated and that solved his problem.

 

[adam32+P]

1/2" and the groups kept walking up the target. Had to adjust elevation to get it back to bulls eye. Also had some fliers.

Hot barrel and/or something loose.

 

[Bret GRAVELINE Graveline]

Did you clean the bore in between trips to the range?

 

[257X50]

Been there.

Mine turned out to be an under torqued scope ring. Check the equipment (rifle/scope). Check everything.

In my case, I had a great group, then beat my head against a wall to understand why it fell apart on the next trip. After 3-4 range trips I was ready to give up. Admittedly, took me that long to figure out. I restarted load development, and a friend said check the scope mounts, stock, every screw, when I spoke to him. Torqued the screws to recommended setting, and solved the issue.

Went back to the sweet spot I found before and had the same result, but POI shifted. That may not solve your issue, but worth a check. For me, I felt dumb about it, but lesson learned.

After that, I have 1 rifle I use to prove if it's me or the equipment. It an old one but tells me if it's a bad day for me or not. I usually take it, but don't shoot it much since I don't hunt with it anymore. I have a tried and true combo. If I shoot another rifle and it seems off, I shoot a 3 round group to tell me if it's me or the other gun……. Sometimes it's a bad day, I have them. Others probably do too

Brings back memories of building big revolvers.......
If neither of us could make it print......
I'd try my High Standard The Victor.....
If it didn't print it was us....too beat up for the day.
Go get pie and coffee......groups wouldn't improve that day